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Gifford RM, Taylor N, Carroll A, Sweeting J, Parsons IT, Stacey MJ, Homer NZM, Tsanas A, Woods DR, Reynolds RM. Assessment of salivary cortisol dynamics in an infantry training exercise: a pilot study. BMJ Mil Health 2024:e002622. [PMID: 38604756 DOI: 10.1136/military-2023-002622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/26/2024] [Indexed: 04/13/2024]
Abstract
INTRODUCTION Measuring cortisol during military training offers insights into physiological responses to stress. We attempted precisely timed, cortisol awakening response (CAR) and pre-sleep cortisol (PSC), and diurnal slope (peak morning minus evening cortisol), during a British Army exercise. We aimed to understand cortisol dynamics and evaluate the feasibility of CAR and PSC in this environment. METHOD Setting: high-intensity, 10-day infantry exercise. Participants: regular infantry soldiers exercising (EX, n=25) or headquarters-based (HQ, n=6). Participants undertook PSC and WAKE and WAKE+30 min samples after 1-2 days, 5-6 days and 9-10 days. Wrist-worn GENEActiv accelerometers were used to assess sleep duration in EX only. Samples taken ±15 min from prespecified time points were deemed adherent. Validated questionnaires were used to measure resilience and perceived stress. Cortisol and cortisone were measured simultaneously by liquid chromatography tandem mass spectrometry. RESULTS From adherent participants' samples, CAR was positive and tended to decrease as the exercise progressed. From all available data, HQ demonstrated greater diurnal slope than EX (F=7.68, p=0.02), reflecting higher morning cortisol (F=4.72, p=0.038) and lower PSC (p=0.04). No differences were seen in cortisol:cortisone ratio. 26.1% of CAR samples were adherent, with moderately strong associations between adherence and stress (r=0.41, p=0.009) but no association between adherence and day of exercise (χ2=0.27, p=0.8), sleep duration (r=-0.112, p=0.43) or resilience (r=-0.79, p=0.75). Test-retest reliability ratings for CAR were Cronbach's α of 0.48, -11.7 and 0.34 for the beginning, middle and end of the exercise, respectively. CONCLUSIONS We observed a reduction in morning cortisol and decreased diurnal slope during a high-intensity military exercise, compared with the HQ comparator cohort in whom diurnal slope was preserved. A carefully timed CAR was not feasible in this setting.
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Affiliation(s)
- Robert M Gifford
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - N Taylor
- Academic Department of Military General Practice, Royal Centre for Defence Medicine, Birmingham, UK
| | - A Carroll
- Royal Centre for Defence Medicine, Birmingham, UK
| | - J Sweeting
- Royal Centre for Defence Medicine, Birmingham, UK
| | - I T Parsons
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - M J Stacey
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - N Z M Homer
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - A Tsanas
- Usher Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - D R Woods
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - R M Reynolds
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
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Parsons IT, Snape D, Stacey MJ, Barlow M, O'Hara J, Gall N, Chowienczyk P, Wainwright B, Woods DR. Improvements in Orthostatic Tolerance with Exercise Are Augmented by Heat Acclimation: A Randomized Controlled Trial. Med Sci Sports Exerc 2024; 56:644-654. [PMID: 38079307 DOI: 10.1249/mss.0000000000003355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2024]
Abstract
INTRODUCTION Heat adaptation is protective against heat illness; however, its role in heat syncope, due to reflex mechanisms, has not been conclusively established. The aim of this study was to evaluate if heat acclimation (HA) was protective against heat syncope and to ascertain underlying physiological mechanisms. METHODS Twenty (15 males, 5 females) endurance-trained athletes were randomized to either 8 d of mixed active and passive HA (HEAT) or climatically temperate exercise (CONTROL). Before, and after, the interventions participants underwent a head up tilt (HUT) with graded lower body negative pressure (LBNP), in a thermal chamber (32.0 ± 0.3°C), continued until presyncope with measurement of cardiovascular parameters. Heat stress tests (HST) were performed to determine physiological and perceptual measures of HA. RESULTS There was a significant increase in orthostatic tolerance (OT), as measured by HUT/LBNP, in the HEAT group (preintervention; 28 ± 9 min, postintervention; 40 ± 7 min) compared with CONTROL (preintervention; 30 ± 8 mins, postintervention; 33 ± 5 min) ( P = 0.01). Heat acclimation resulted in a significantly reduced peak and mean rectal and skin temperature ( P < 0.01), peak heat rate ( P < 0.003), thermal comfort ( P < 0.04), and rating of perceived exertion ( P < 0.02) during HST. There was a significantly increased plasma volume (PV) in the HEAT group in comparison to CONTROL ( P = 0.03). CONCLUSIONS Heat acclimation causes improvements in OT and is likely to be beneficial in patients with heat exacerbated reflex syncope. Heat acclimation-mediated PV expansion is a potential physiological mechanism underlying improved OT.
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Affiliation(s)
| | - Daniel Snape
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Michael J Stacey
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UNITED KINGDOM
| | - Matthew Barlow
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - John O'Hara
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Nick Gall
- School of Cardiovascular Medicine and Sciences, King's College London, London, UNITED KINGDOM
| | - Phil Chowienczyk
- School of Cardiovascular Medicine and Sciences, King's College London, London, UNITED KINGDOM
| | - Barney Wainwright
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
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Parsons IT, Ellwood J, Stacey MJ, Gall N, Chowienczyk P, Woods DR. Risk factors for reflex syncope in the British Army. BMJ Mil Health 2023; 169:548-553. [PMID: 35177430 DOI: 10.1136/bmjmilitary-2021-002040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/29/2022] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Reflex syncope in the UK Armed Forces is reportedly higher than comparable militaries and civilian populations and is significantly more common in soldiers who take part in State Ceremonial and Public Duties (SCPD) compared with other British Army service personnel (SP). This study aimed to investigate individual susceptibility factors for syncope in soldiers who regularly take part in SCPD. METHODS A retrospective cohort study was performed in 200 soldiers who perform SCPD. A questionnaire was undertaken reviewing soldiers' medical history and circumstances of any fainting episodes. A consented review of participants' electronic primary healthcare medical record was also performed. Participants were divided into two groups (syncope, n=80; control, n=120) based on whether they had previously fainted. RESULTS In the syncope group orthostasis (61%) and heat (35%) were the most common precipitating factors. The most common interventions used by soldiers were to maintain hydration (59%) and purposeful movements (predominantly 'toe wiggling'; 55%). 30% of participants who had previously fainted did not seek definitive medical attention. A history of migraines/headaches was found to increase the risk of reflex syncope (OR 8.880, 1.214-218.8), while a history of antihistamine prescription (OR 0.07144, 0.003671-0.4236), non-white ethnicity (OR 0.03401, 0.0007419-0.3972) and male sex (OR 0.2640, 0.08891-0.6915) were protective. CONCLUSION This is the first study, in the British Army, to describe, categorise and establish potential risk factors for reflex syncope. Orthostatic-mediated reflex syncope is the most common cause in soldiers who regularly perform SCPD and this is further exacerbated by heat exposure. Soldiers do not use evidence-based methods to avoid reflex syncope. These data could be used to target interventions for SP who have previously fainted or to prevent fainting during SCPD.
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Affiliation(s)
- Iain T Parsons
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
- School of Life Sciences and Medicine, King's College London, London, UK
| | - J Ellwood
- Defence Primary Healthcare, George Guthrie Medical Centre, Wellington Barracks, London, UK
| | - M J Stacey
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - N Gall
- Department of Cardiology, King's College Hospital, London, UK
| | - P Chowienczyk
- School of Life Sciences and Medicine, King's College London, London, UK
| | - D R Woods
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
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Stacey MJ, Leckie T, Fitzpatrick D, Hodgson L, Barden A, Jenkins R, Galloway R, Weller C, Grivas GV, Pitsiladis Y, Richardson AJ, Woods DR. Neurobiomarker and body temperature responses to recreational marathon running. J Sci Med Sport 2023; 26:566-573. [PMID: 37777396 DOI: 10.1016/j.jsams.2023.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 10/02/2023]
Abstract
OBJECTIVES To assess how biomarkers indicating central nervous system insult (neurobiomarkers) vary in peripheral blood with exertional-heat stress from prolonged endurance exercise. DESIGN Observational study of changes in neuron specific enolase (NSE), S100 calcium-binding protein B (S100β), Glial Fibrillary Acid Protein (GFAP) and Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1) at Brighton Marathon 2022. METHODS In 38 marathoners with in-race core temperature (Tc) monitoring, exposure (High, Intermediate or Low) was classified by cumulative hyperthermia - calculated as area under curve of Time × Tc > 38 °C - and also by running duration (finishing time). Blood was sampled for neurobiomarkers, cortisol and fluid-regulatory stress surrogates, including copeptin and creatinine (at rested baseline; within 30 min of finishing; and at 24 h). RESULTS Finishing in 236 ± 40 min, runners showed stable GFAP and UCH-L1 across the marathon and next-day. Significant (P < 0.05) increases from baseline were shown post-marathon and at 24 h for S100β (8.52 [3.65, 22.95] vs 39.0 [26.48, 52.33] vs 80.3 [49.1, 99.7] ng·L-1) and post-marathon only for NSE (3.73 [3.30, 4.32] vs 4.85 [4.45, 5.80] μg·L-1, P < 0.0001). Whilst differential response to hyperthermia was observed for cortisol, copeptin and creatinine, neurobiomarker responses did not vary. Post-marathon, only NSE differed by exercise duration (High vs Low, 5.81 ± 1.77 vs. 4.69 ± 0.73 μg·L-1, adjusted P = 0.0358). CONCLUSIONS Successful marathon performance did not associate with evidence for substantial neuronal insult. To account for variation in neurobiomarkers with prolonged endurance exercise, factors additional to hyperthermia, such as exercise duration and intensity, should be further investigated.
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Affiliation(s)
- M J Stacey
- Academic Department of Military Medicine, Defence Medical Services, UK; Carnegie School of Sport, Leeds Beckett University, UK; Department of Surgery and Cancer, Imperial College London, UK.
| | - T Leckie
- School of Sport and Health Sciences, University of Brighton, UK
| | - D Fitzpatrick
- School of Sport and Health Sciences, University of Brighton, UK; Sport and Exercise Medicine Department, Charing Cross Hospital, UK
| | - L Hodgson
- Brighton & Sussex Medical School, Brighton, UK
| | - A Barden
- School of Medicine, Imperial College London, UK
| | - R Jenkins
- Foundation Programme, Defence Medical Services, UK
| | - R Galloway
- Brighton & Sussex Medical School, Brighton, UK
| | - C Weller
- Brighton & Sussex Medical School, Brighton, UK
| | - G V Grivas
- Division of Humanities and Political Sciences, Physical Education and Sports, Hellenic Naval Academy, Greece
| | - Y Pitsiladis
- School of Sport and Health Sciences, University of Brighton, UK; Human Telemetrics, UK
| | - A J Richardson
- School of Sport and Health Sciences, University of Brighton, UK
| | - D R Woods
- Academic Department of Military Medicine, Defence Medical Services, UK; Carnegie School of Sport, Leeds Beckett University, UK
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Snape D, Wainwright B, Woods DR, O'Hara JP. Reliability of Biomarkers of Physiological Stress at Rest and Post-exertional Heat Stress. Int J Sports Med 2023; 44:184-191. [PMID: 35777726 DOI: 10.1055/a-1890-0993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The purpose of this study was to assess the reliability of blood biomarkers that can signify exercise-induced heat stress in hot conditions. Fourteen males completed two heat stress tests separated by 5-7 days. Venous blood was drawn pre- and post- heat stress for the concentration of normetanephrine, metanephrine, serum osmolality, copeptin, kidney-injury molecule 1, and neutrophil gelatinase-associated lipocalin. No biomarker, except copeptin, displayed systematic trial order bias (p≥0.05). Normetanephrine, copeptin and neutrophil gelatinase-associated lipocalin presented acceptable reliability (CV range: 0.9-14.3%), while greater variability was present in metanephrine, osmolality and kidney-injury molecule 1 (CV range: 28.6-43.2%). Normetanephrine exhibited the largest increase (p<0.001) in response to heat stress (trial 1=1048±461 pmol. L-1; trial 2=1067±408 pmol. L-1), whilst kidney-injury molecule 1 presented trivial changes (trial 1=-4±20 ng. L-1; trial 2=2 ± 16 ng. L-1, p>0.05). Normetanephrine, copeptin, and neutrophil gelatinase-associated lipocalin demonstrated good reliability and sensitivity to an acute bout of heat stress. These biomarkers may be suitable for application in laboratory and field research to understand the efficacy of interventions that can attenuate the risk of thermal injury whilst exercising in the heat.
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Affiliation(s)
- Daniel Snape
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - Barney Wainwright
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - David R Woods
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom of Great Britain and Northern Ireland.,Academic Medicine, Royal Centre for Defence Medicine, Birmingham, United Kingdom of Great Britain and Northern Ireland
| | - John Paul O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom of Great Britain and Northern Ireland
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Gifford RM, Taylor N, Stacey M, Woods DR. Sex, gender or occupational psychology: what matters most to preventing heat-related illnesses and improving outcomes for women in ground close combat? BMJ Mil Health 2023; 169:75-77. [PMID: 32345677 DOI: 10.1136/bmjmilitary-2020-001480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 01/27/2023]
Abstract
Since the advent of women in ground close combat (WGCC) roles, the impact on women of the attendant risk of heat stress and heat illness has been considered. Much emphasis has been placed on sex differences in thermal physiology. This article considers the application of evidence of sex-associated thermoregulatory variation to the occupational and environmental setting of WGCC, and weighs the relative importance of physiological differences arising from biological sex, and behaviour associated with gender normatives. Quantifying the risk of heat illness to WGCC should draw on data from their real-world occupational context.
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Affiliation(s)
- Robert M Gifford
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK.,Academic Department of Military Medicine, HQ Joint Medical Group, Birmingham, UK
| | - N Taylor
- Academic Department of Military Medicine, HQ Joint Medical Group, Birmingham, UK
| | - M Stacey
- Academic Department of Military Medicine, HQ Joint Medical Group, Birmingham, UK
| | - D R Woods
- Academic Department of Military Medicine, HQ Joint Medical Group, Birmingham, UK.,Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University Carnegie Faculty, Leeds, UK
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Giannos P, Prokopidis K, Church DD, Kirk B, Morgan PT, Lochlainn MN, Macpherson H, Woods DR, Ispoglou T. Associations of Bioavailable Serum Testosterone With Cognitive Function in Older Men: Results From the National Health and Nutrition Examination Survey. J Gerontol A Biol Sci Med Sci 2023; 78:151-157. [PMID: 35927217 PMCID: PMC9879757 DOI: 10.1093/gerona/glac162] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Age-associated cognitive decline may be influenced by testosterone status. However, studies evaluating the impact of bioavailable testosterone, the active, free testosterone, on cognitive function are scarce. Our study determined the relationship between calculated bioavailable testosterone and cognitive performance in older men. METHODS We used data from the U.S. National Health and Nutrition Examination Survey (NHANES) between 2013 and 2014. This study consisted of 208 men aged ≥60 years. Bioavailable serum testosterone was calculated based on the total serum testosterone, sex hormone-binding globulin, and albumin levels, whereas cognitive performance was assessed through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test (WLLT), Word List Recall Test (WLRT), and Intrusion Word Count Test (WLLT-IC and WLRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Multiple linear regression analyses were performed upon adjustment for age, ethnicity, socioeconomic status, education level, medical history, body mass index, energy, alcohol intake, physical activity levels, and sleep duration. RESULTS A significant positive association between bioavailable testosterone and DSST (β: 0.049, p = .002) score was detected, with no signs of a plateau effect. No significant associations with CERAD WLLT (p = .132), WLRT (p = .643), WLLT-IC (p = .979), and WLRT-IC (p = .387), and AFT (p = .057) were observed. CONCLUSION Calculated bioavailable testosterone presented a significant positive association with processing speed, sustained attention, and working memory in older men above 60 years of age. Further research is warranted to elucidate the impact of the inevitable age-related decline in testosterone on cognitive function in older men.
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Affiliation(s)
- Panagiotis Giannos
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK.,Society of Meta-research and Biomedical Innovation, London, UK
| | - Konstantinos Prokopidis
- Society of Meta-research and Biomedical Innovation, London, UK.,Department of Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - David D Church
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, Center for Translational Research in Aging and Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ben Kirk
- Department of Medicine-Western Health, Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Melbourne, Victoria, Australia
| | - Paul T Morgan
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.,Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, UK
| | - Mary Ni Lochlainn
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Helen Macpherson
- Deakin University, Geelong, Victoria, Australia.,Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Burwood, Victoria, Australia
| | - David R Woods
- Defence Medical Services, Lichfield, UK.,Carnegie School of Sport, Leeds Beckett University, Leeds, UK
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Parsons IT, Hockin BCD, Taha OM, Heeney ND, Williams EL, Lucci VEM, Lee RHY, Stacey MJ, Gall N, Chowienczyk P, Woods DR, Claydon VE. The effect of water temperature on orthostatic tolerance: a randomised crossover trial. Clin Auton Res 2022; 32:131-141. [PMID: 35461434 PMCID: PMC9064858 DOI: 10.1007/s10286-022-00860-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/17/2022] [Indexed: 11/04/2022]
Abstract
Purpose Bolus water drinking, at room temperature, has been shown to improve orthostatic tolerance (OT), probably via sympathetic activation; however, it is not clear whether the temperature of the water bolus modifies the effect on OT or the cardiovascular responses to orthostatic stress. The aim of this study was to assess whether differing water temperature of the water bolus would alter time to presyncope and/or cardiovascular parameters during incremental orthostatic stress. Methods Fourteen participants underwent three head-up tilt (HUT) tests with graded lower body negative pressure (LBNP) continued until presyncope. Fifteen minutes prior to each HUT, participants drank a 500 mL bolus of water which was randomised, in single-blind crossover fashion, to either room temperature water (20 °C) (ROOM), ice-cold water (0–3 °C) (COLD) or warm water (45 °C) (WARM). Cardiovascular parameters were monitored continuously. Results There was no significant difference in OT in the COLD (33 ± 3 min; p = 0.3321) and WARM (32 ± 3 min; p = 0.6764) conditions in comparison to the ROOM condition (31 ± 3 min). During the HUT tests, heart rate and cardiac output were significantly reduced (p < 0.0073), with significantly increased systolic blood pressure, stroke volume, cerebral blood flow velocity and total peripheral resistance (p < 0.0054), in the COLD compared to ROOM conditions. Conclusions In healthy controls, bolus cold water drinking results in favourable orthostatic cardiovascular responses during HUT/LBNP without significantly altering OT. Using a cold water bolus may result in additional benefits in patients with orthostatic intolerance above those conferred by bolus water at room temperature (by ameliorating orthostatic tachycardia and enhancing vascular resistance responses). Further research in patients with orthostatic intolerance is warranted.
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Stacey MJ, Hill NE, Parsons IT, Wallace J, Taylor N, Grimaldi R, Shah N, Marshall A, House C, O’Hara JP, Brett SJ, Woods DR. Relative changes in brain and kidney biomarkers with Exertional Heat Illness during a cool weather marathon. PLoS One 2022; 17:e0263873. [PMID: 35176088 PMCID: PMC8853487 DOI: 10.1371/journal.pone.0263873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 01/29/2022] [Indexed: 11/18/2022] Open
Abstract
Background
Medical personnel may find it challenging to distinguish severe Exertional Heat Illness (EHI), with attendant risks of organ-injury and longer-term sequalae, from lesser forms of incapacity associated with strenuous physical exertion. Early evidence for injury at point-of-incapacity could aid the development and application of targeted interventions to improve outcomes. We aimed to investigate whether biomarker surrogates for end-organ damage sampled at point-of-care (POC) could discriminate EHI versus successful marathon performance.
Methods
Eight runners diagnosed as EHI cases upon reception to medical treatment facilities and 30 successful finishers of the same cool weather marathon (ambient temperature 8 rising to 12 ºC) were recruited. Emerging clinical markers associated with injury affecting the brain (neuron specific enolase, NSE; S100 calcium-binding protein B, S100β) and renal system (cystatin C, cysC; kidney-injury molecule-1, KIM-1; neutrophil gelatinase-associated lipocalin, NGAL), plus copeptin as a surrogate for fluid-regulatory stress, were sampled in blood upon marathon collapse/completion, as well as beforehand at rest (successful finishers only).
Results
Versus successful finishers, EHI showed significantly higher NSE (10.33 [6.37, 20.00] vs. 3.17 [2.71, 3.92] ug.L-1, P<0.0001), cysC (1.48 [1.10, 1.67] vs. 1.10 [0.95, 1.21] mg.L-1, P = 0.0092) and copeptin (339.4 [77.0, 943] vs. 18.7 [7.1, 67.9] pmol.L-1, P = 0.0050). Discrimination of EHI by ROC (Area-Under-the-Curve) showed performance that was outstanding for NSE (0.97, P<0.0001) and excellent for copeptin (AUC = 0.83, P = 0.0066).
Conclusions
As novel biomarker candidates for EHI outcomes in cool-weather endurance exercise, early elevations in NSE and copeptin provided sufficient discrimination to suggest utility at point-of-incapacity. Further investigation is warranted in patients exposed to greater thermal insult, followed up over a more extended period.
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Affiliation(s)
- Michael J. Stacey
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
- * E-mail:
| | - Neil E. Hill
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Iain T. Parsons
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
- School of Cardiovascular Medicine and Sciences, King’s College London, London, United Kingdom
| | | | | | - Rachael Grimaldi
- Brighton and Sussex University Hospitals NHS Trust, Brighton, United Kingdom
| | - Nishma Shah
- University College London, London, United Kingdom
| | | | - Carol House
- Environmental Medicine Services, Institute of Naval Medicine, Gosport, United Kingdom
| | - John P. O’Hara
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
| | - Stephen J. Brett
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
- General Intensive Care Unit, Hammersmith Hospital, London, United Kingdom
| | - David R. Woods
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
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Elia A, Woods DR, Barlow MJ, Lees MJ, O'Hara JP. Cerebral, cardiac and skeletal muscle stress associated with a series of static and dynamic apnoeas. Scand J Med Sci Sports 2021; 32:233-241. [PMID: 34597427 DOI: 10.1111/sms.14067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 09/21/2021] [Accepted: 09/28/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE This study sought to explore, for the first time, the effects of repeated maximal static and dynamic apnoeic attempts on the physiological milieu by assessing cerebral, cardiac and striatal muscle stress-related biomarkers in a group of elite breath-hold divers (EBHD). METHODS Sixteen healthy males were recruited (EBHD = 8; controls = 8). On two separate occasions, EBHD performed two sets of five repeated maximal static apnoeas (STA) or five repeated maximal dynamic apnoeas (DYN). Controls performed a static eupnoeic protocol to negate any effects of water immersion and diurnal variation on haematology (CTL). Venous blood samples were drawn at 30, 90, and 180 min after each protocol to determine S100β, neuron-specific enolase (NSE), myoglobin, and high sensitivity cardiac troponin T (hscTNT) concentrations. RESULTS S100β and myoglobin concentrations were elevated following both apnoeic interventions (p < 0.001; p ≤ 0.028, respectively) but not after CTL (p ≥ 0.348). S100β increased from baseline (0.024 ± 0.005 µg/L) at 30 (STA, +149%, p < 0.001; DYN, +166%, p < 0.001) and 90 min (STA, +129%, p < 0.001; DYN, +132%, p = 0.008) following the last apnoeic repetition. Myoglobin was higher than baseline (22.3 ± 2.7 ng/ml) at 30 (+42%, p = 0.04), 90 (+64%, p < 0.001) and 180 min (+49%, p = 0.013) post-STA and at 90 min (+63%, p = 0.016) post-DYN. Post-apnoeic S100β and myoglobin concentrations were higher than CTL (STA, p < 0.001; DYN, p ≤ 0.004). NSE and hscTNT did not change from basal concentrations after the apnoeic (p ≥ 0.146) nor following the eupnoeic (p ≥ 0.553) intervention. CONCLUSIONS This study suggests that a series of repeated maximal static and dynamic apnoeas transiently disrupt the blood-brain barrier and instigate muscle injury but do not induce neuronal-parenchymal damage or myocardial damage.
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Affiliation(s)
- Antonis Elia
- Division of Environmental Physiology, School of Chemistry, Bioengineering and Health, KTH Royal Institute of Technology, Stockholm, Sweden.,Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - David R Woods
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK.,Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | | | - Matthew J Lees
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - John P O'Hara
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK
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11
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Anand P, Privitera R, Donatien P, Misra VP, Woods DR. Capsaicin 8% Patch Treatment in Non-Freezing Cold Injury: Evidence for Pain Relief and Nerve Regeneration. Front Neurol 2021; 12:722875. [PMID: 34489857 PMCID: PMC8418325 DOI: 10.3389/fneur.2021.722875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/21/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Neuropathic pain associated with Non-freezing Cold Injury (NFCI) is a major burden to military service personnel. A key feature of NFCI is reduction of the intra-epidermal nerve fibre density in skin biopsies, in keeping with painful neuropathy. Current oral treatments are generally ineffective and have undesirable side effects. Capsaicin 8% patch (Qutenza) has been shown to be well-tolerated and effective for reducing neuropathic pain, for up to 3 months after a single 30-minute application. Methods: In this single-centre open label study, 16 military participants with NFCI (mean duration 49 months) received 30-minute Capsaicin 8% patch treatment to the feet and distal calf. Pain symptoms were assessed using a pain diary (with the 11-point Numerical Pain Rating Scale, NPRS) and questionnaires, the investigations included skin biopsies, performed before and three months after treatment. Results: Participants showed significant decrease in spontaneous pain (mean NPRS: −1.1, 95% CI: 0.37 to 1.90; p = 0.006), and cold-evoked pain (−1.2, 95% CI: 0.40 to 2.04; p = 0.006). The time-course of pain relief over 3 months was similar to other painful neuropathies. Patient Global Impression of Change showed improvement (p = 0.0001). Skin punch biopsies performed 3 months after the patch application showed significant increase of nerve fibres with structural marker PGP9.5 (intra-epidermal nerve fibres [IENFs], p < 0.0001; sub-epidermal nerve fibres [SENFs]; p =< 0.0001), and of regenerating nerve fibres with their selective marker GAP43 (p = 0.0001). The increase of IENFs correlated with reduction of spontaneous (p = 0.027) and cold-evoked pain (p = 0.019). Conclusions: Capsaicin 8% patch provides an exciting new prospect for treatment of NFCI, with regeneration and restoration of nerve fibres, for the first time, in addition to pain relief.
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Affiliation(s)
- Praveen Anand
- Department of Neurology, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Rosario Privitera
- Department of Neurology, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Philippe Donatien
- Department of Neurology, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - V Peter Misra
- Department of Neurology, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - David R Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom.,Leeds Beckett University, Leeds, United Kingdom
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12
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O'Leary TJ, Wardle SL, Double RL, Gifford RM, Reynolds RM, Woods DR, Greeves JP. Influence Of Hormonal Contraceptive Use On Tibial Microarchitecture Adaptations To British Army Officer Training. Med Sci Sports Exerc 2021. [DOI: 10.1249/01.mss.0000760464.68328.f0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Greeves JP, Wardle SL, Double RL, Gifford RM, Reynolds RM, Woods DR, O'Leary TJ. Influence Of Hormonal Contraceptive Use On Bone Metabolic Responses To British Army Officer Basic Training. Med Sci Sports Exerc 2021. [DOI: 10.1249/01.mss.0000760468.73365.8b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Parsons IT, Gifford RM, Stacey MJ, Lamb LE, O'Shea MK, Woods DR. Does vitamin D supplementation prevent SARS-CoV-2 infection in military personnel? Review of the evidence. BMJ Mil Health 2021; 167:280-286. [PMID: 33504571 PMCID: PMC7843210 DOI: 10.1136/bmjmilitary-2020-001686] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/15/2020] [Accepted: 11/21/2020] [Indexed: 01/19/2023]
Abstract
For most individuals residing in Northwestern Europe, maintaining replete vitamin D status throughout the year is unlikely without vitamin D supplementation and deficiency remains common. Military studies have investigated the association with vitamin D status, and subsequent supplementation, with the risk of stress fractures particularly during recruit training. The expression of nuclear vitamin D receptors and vitamin D metabolic enzymes in immune cells additionally provides a rationale for the potential role of vitamin D in maintaining immune homeostasis. One particular area of interest has been in the prevention of acute respiratory tract infections (ARTIs). The aims of this review were to consider the evidence of vitamin D supplementation in military populations in the prevention of ARTIs, including SARS-CoV-2 infection and consequent COVID-19 illness. The occupational/organisational importance of reducing transmission of SARS-CoV-2, especially where infected young adults may be asymptomatic, presymptomatic or paucisymptomatic, is also discussed.
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Affiliation(s)
- Iain T Parsons
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
- School of Cardiovascular Medicine and Life Sciences, King's College London, London, UK
| | - R M Gifford
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, Midlothian, UK
| | - M J Stacey
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - L E Lamb
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - M K O'Shea
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - D R Woods
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK
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15
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Gifford RM, O'Leary TJ, Wardle SL, Double RL, Homer NZM, Howie AF, Greeves JP, Anderson RA, Woods DR, Reynolds RM. Reproductive and metabolic adaptation to multistressor training in women. Am J Physiol Endocrinol Metab 2021; 321:E281-E291. [PMID: 34191631 DOI: 10.1152/ajpendo.00019.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/07/2021] [Indexed: 11/22/2022]
Abstract
Hypothalamic-pituitary-gonadal (HPG) axis suppression in exercising women can be caused by low energy availability (EA), but the impact of a real-world, multistressor training environment on reproductive and metabolic function is unknown. This study aimed to characterize reproductive and metabolic adaptation in women undertaking basic military training. A prospective cohort study in women undertaking 11-month initial military training (n = 47) was carried out. Dynamic low-dose 1-h gonadotrophin-releasing hormone (GnRH) tests were completed after 0 and 7 mo of training. Urine progesterone was sampled weekly throughout. Body composition (dual X-ray absorptiometry), fasting insulin resistance (homeostatic modeling assessment 2, HOMA2), leptin, sex steroids, anti-Müllerian hormone (AMH), and inhibin B were measured after 0, 7, and 11 mo with an additional assessment of body composition at 3 mo. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) responses were suppressed after 7 mo (both P < 0.001). Among noncontraceptive users (n = 20), 65% had regular (23-35 days) cycles preenrollment, falling to 24% by 7 mo of training. Of women in whom urine progesterone was measured (n = 24), 87% of cycles showed no evidence of ovulation. There was little change in AMH, LH, and estradiol, although inhibin B and FSH increased (P < 0.05). Fat mass fluctuated during training but at month 11 was unchanged from baseline. Fat-free mass did not change. Visceral adiposity, HOMA2, and leptin increased (all P < 0.001). HPG axis suppression with anovulation occurred in response to training without evidence of low EA. Increased insulin resistance may have contributed to the observed pituitary and ovarian dysfunction. Our findings are likely to represent an adaptive response of reproductive function to the multistressor nature of military training.NEW & NOTEWORTHY We characterized reproductive endocrine adaptation to prolonged arduous multistressor training in women. We identified marked suppression of hypothalamic-pituitary-gonadal (HPG) axis function during training but found no evidence of low energy availability despite high energy requirements. Our findings suggest a complex interplay of psychological and environmental stressors with suppression of the HPG axis via activation of the hypothalamic-pituitary adrenal (HPA) axis. The neuroendocrine impact of nonexercise stressors on the HPG axis during arduous training should be considered.
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Affiliation(s)
- Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Research & Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
| | - Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Rebecca L Double
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
| | - Natalie Z M Homer
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - A Forbes Howie
- Medical Research Council Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
| | - Richard A Anderson
- Medical Research Council Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - David R Woods
- Research & Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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16
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O'Leary TJ, Wardle SL, Gifford RM, Double RL, Reynolds RM, Woods DR, Greeves JP. Tibial Macrostructure and Microarchitecture Adaptations in Women During 44 Weeks of Arduous Military Training. J Bone Miner Res 2021; 36:1300-1315. [PMID: 33856703 DOI: 10.1002/jbmr.4290] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/01/2021] [Accepted: 03/12/2021] [Indexed: 12/14/2022]
Abstract
Bone adapts to unaccustomed, high-impact loading but loses mechanosensitivity quickly. Short periods of military training (≤12 weeks) increase the density and size of the tibia in women. The effect of longer periods of military training, where the incidence of stress fracture is high, on tibial macrostructure and microarchitecture in women is unknown. This observational study recruited 51 women (age 19 to 30 years) at the start of 44 weeks of British Army Officer training. Tibial volumetric bone mineral density (vBMD), geometry, and microarchitecture were measured by high-resolution peripheral quantitative computed tomography (HRpQCT). Scans of the right tibial metaphysis (4% site) and diaphysis (30% site) were performed at weeks 1, 14, 28, and 44. Measures of whole-body areal bone mineral density (aBMD) were obtained using dual-energy X-ray absorptiometry (DXA). Blood samples were taken at weeks 1, 28, and 44, and were analyzed for markers of bone formation and resorption. Trabecular vBMD increased from week 1 to 44 at the 4% site (3.0%, p < .001). Cortical vBMD decreased from week 1 to 14 at the 30% site (-0.3%, p < .001). Trabecular area decreased at the 4% site (-0.4%); trabecular bone volume fraction (3.5%), cortical area (4.8%), and cortical thickness (4.0%) increased at the 4% site; and, cortical perimeter increased at the 30% site (0.5%) from week 1 to 44 (p ≤ .005). Trabecular number (3.5%) and thickness (2.1%) increased, and trabecular separation decreased (-3.1%), at the 4% site from week 1 to 44 (p < .001). Training increased failure load at the 30% site from week 1 to 44 (2.5%, p < .001). Training had no effect on aBMD or markers of bone formation or resorption. Tibial macrostructure and microarchitecture continued to adapt across 44 weeks of military training in young women. Temporal decreases in cortical density support a role of intracortical remodeling in the pathogenesis of stress fracture. © 2021 Crown copyright. Journal of Bone and Mineral Research © 2021 American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.
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Affiliation(s)
- Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, UK.,Division of Surgery and Interventional Science, University College London (UCL), London, UK
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, UK.,Division of Surgery and Interventional Science, University College London (UCL), London, UK
| | - Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.,Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - Rebecca L Double
- Army Health and Performance Research, Army Headquarters, Andover, UK
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - David R Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.,Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.,Northumbria and Newcastle National Health Service (NHS) Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK.,University of Newcastle, Newcastle, UK
| | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, UK.,Division of Surgery and Interventional Science, University College London (UCL), London, UK.,Norwich Medical School, University of East Anglia, Norwich, UK
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17
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Marshall AR, Rimmer JE, Shah N, Bye K, Kipps C, Woods DR, O'Hara J, Boos CJ, Barlow M. Marching to the Beet: The effect of dietary nitrate supplementation on high altitude exercise performance and adaptation during a military trekking expedition. Nitric Oxide 2021; 113-114:70-77. [PMID: 34051342 DOI: 10.1016/j.niox.2021.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/19/2021] [Accepted: 05/23/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE The aim was to investigate the effect of dietary nitrate supplementation (in the form of beetroot juice, BRJ) for 20 days on salivary nitrite (a potential precursor of bioactive nitric oxide), exercise performance and high altitude (HA) acclimatisation in field conditions (hypobaric hypoxia). METHODS This was a single-blinded randomised control study of 22 healthy adult participants (12 men, 10 women, mean age 28 ± 12 years) across a HA military expedition. Participants were randomised pre-ascent to receive two 70 ml dose per day of either BRJ (~12.5 mmol nitrate per day; n = 11) or non-nitrate calorie matched control (n = 11). Participants ingested supplement doses daily, beginning 3 days prior to departure and continued until the highest sleeping altitude (4800 m) reached on day 17 of the expedition. Data were collected at baseline (44 m altitude), at 2350 m (day 9), 3400 m (day 12) and 4800 m (day 17). RESULTS BRJ enhanced the salivary levels of nitrite (p = 0.007). There was a significant decrease in peripheral oxygen saturation and there were increases in heart rate, diastolic blood pressure, and rating of perceived exertion with increasing altitude (p=<0.001). Harvard Step Test fitness scores significantly declined at 4800 m in the control group (p = 0.003) compared with baseline. In contrast, there was no decline in fitness scores at 4800 m compared with baseline (p = 0.26) in the BRJ group. Heart rate recovery speed following exercise at 4800 m was significantly prolonged in the control group (p=<0.01) but was unchanged in the BRJ group (p = 0.61). BRJ did not affect the burden of HA illness (p = 1.00). CONCLUSIONS BRJ increases salivary nitrite levels and ameliorates the decline in fitness at altitude but does not affect the occurrence of HA illness.
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Affiliation(s)
- Anna R Marshall
- Department of Surgical and Interventional Sciences, Institute of Sport, Exercise & Health, UCL, London, WC1E 6B, UK.
| | | | - Nishma Shah
- Department of Surgical and Interventional Sciences, Institute of Sport, Exercise & Health, UCL, London, WC1E 6B, UK
| | - Kyo Bye
- Defence Medical Services, Lichfield, WS14 9PY, UK
| | - Courtney Kipps
- Department of Surgical and Interventional Sciences, Institute of Sport, Exercise & Health, UCL, London, WC1E 6B, UK
| | - David R Woods
- Defence Medical Services, Lichfield, WS14 9PY, UK; Carneige School of Sport, Leeds Beckett University, Leeds, LS16 5LF, UK; Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, NE66 2NS, UK
| | - John O'Hara
- Carneige School of Sport, Leeds Beckett University, Leeds, LS16 5LF, UK
| | - Christopher J Boos
- Carneige School of Sport, Leeds Beckett University, Leeds, LS16 5LF, UK; Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, BH15 2JB, UK; Department of Postgraduate Medical Education, Bournemouth University, Bournemouth, BH1 3LT, UK
| | - Matthew Barlow
- Carneige School of Sport, Leeds Beckett University, Leeds, LS16 5LF, UK
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18
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Gifford RM, Greeves JP, Wardle SL, O'Leary TJ, Double RL, Venables M, Boos C, Langford J, Woods DR, Reynolds RM. Measuring the Exercise Component of Energy Availability during Arduous Training in Women. Med Sci Sports Exerc 2021; 53:860-868. [PMID: 33017351 DOI: 10.1249/mss.0000000000002527] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Low energy availability (EA) may impede adaptation to exercise, suppressing reproductive function and bone turnover. Exercise energy expenditure (EEE) measurements lack definition and consistency. This study aimed to compare EA measured from moderate and vigorous physical activity from accelerometry (EEEmpva) with EA from total physical activity (EEEtpa) from doubly labeled water in women. The secondary aim was to determine the relationship of EA with physical fitness, body composition by dual-energy x-ray absorptiometry, heart rate variability (HRV), and eating behavior (Brief Eating Disorder in Athletes Questionnaire [BEDA-Q]). METHODS This was a prospective, repeated-measures study, assessing EA measures and training adaptation during 11-month basic military training. Forty-seven women (23.9 ± 2.6 yr) completed three consecutive 10-d assessments of EEEmvpa, EEEtpa, and energy intake (EI). EA measures were compared using linear regression and Bland-Altman analyses; relationships of EA with fat mass, HRV, 1.5-mile run times, and BEDA-Q were evaluated using partial correlations. RESULTS EA from EEEmvpa demonstrated strong agreement with EA from EEEtpa across the measurement range (R2 = 0.76, r = 0.87, P < 0.001) and was higher by 10 kcal·kg-1 FFM·d-1. However, EA was low in absolute terms because of underreported EI. Higher EA was associated with improved 1.5-mile run time (r = 0.28, P < 0.001), fat mass loss (r = 0.38, P < 0.001), and lower BEDA-Q score (r = -0.37, P < 0.001) but not HRV (all P > 0.10). CONCLUSION Accelerometry-based EEE demonstrated validity against doubly labeled water during multistressor training, the difference representing 10 kcal·kg-1 FFM·d-1 EEE from nonexercise activity. Beneficial physical but not autonomic adaptations were associated with higher EA. EAmvpa and BEDA-Q warrant consideration for low EA assessment and screening.
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Affiliation(s)
| | | | - Sophie L Wardle
- Army Health and Physical Performance Research, Andover, UNITED KINGDOM
| | - Thomas J O'Leary
- Army Health and Physical Performance Research, Andover, UNITED KINGDOM
| | | | - Michelle Venables
- Medical Research Council Elsie Widdowson Laboratory, Cambridge, UNITED KINGDOM
| | - Christopher Boos
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | | | | | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UNITED KINGDOM
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19
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Parsons IT, Parsons AT, Balme E, Hazell G, Gifford R, Stacey M, Woods DR, Russell-Jones D. The use of routine blood tests to assist the diagnosis of COVID-19 in symptomatic hospitalized patients. Ann Clin Biochem 2021; 58:318-326. [PMID: 33591793 PMCID: PMC8258729 DOI: 10.1177/0004563221999076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Introduction Specific patterns of blood test results are associated with COVID-19 infection. The aim of this study was to identify which blood tests could be used to assist in diagnosing COVID-19. Method A retrospective review was performed on consecutive patients referred to hospital with a clinical suspicion of COVID-19 over a period of four weeks. The patient’s clinical presentation and severe acute respiratory syndrome coronavirus 2 reverse-transcription polymerase chain reaction (SARS-CoV-2 RT-PCR) were recorded. The patients were divided by diagnosis into COVID (COVID-19 infection) or CONTROL (an alternate diagnosis). A retrospective review of consecutive patients over a further two-week period was used for the purposes of validation. Results Overall, 399 patients (53% COVID, 47% CONTROL) were analysed. White cell count, neutrophils and lymphocytes were significantly lower, while lactate dehydrogenase and ferritin were significantly higher, in the COVID group in comparison to CONTROL. Combining the white cell count, lymphocytes and ferritin results into a COVID Combined Blood Test (CCBT) had an area under the curve of 0.79. Using a threshold CCBT of –0.8 resulted in a sensitivity of 0.85 and a specificity of 0.63. Analysing this against a further retrospective review of 181 suspected COVID-19 patients, using the same CCBT threshold, resulted in a sensitivity of 0.73 and a specificity of 0.75. The sensitivity was comparable to the SARS-CoV-2 RT PCR. Discussion Mathematically combining the blood tests has the potential to assist clinical acumen allowing for rapid streaming and more accurate patient flow pending definitive diagnosis. This may be of particular use in low-resource settings.
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Affiliation(s)
- I T Parsons
- School of Life Sciences and Medicine, King's College London, St Thomas' Hospital, London, UK
| | - A T Parsons
- School of Electronic, Electrical & Systems Engineering, Edgbaston, University of Birmingham, Birmingham, UK
| | - E Balme
- Royal Surrey County Hospital NHS Trust, Guildford, UK
| | - G Hazell
- Royal Surrey County Hospital NHS Trust, Guildford, UK
| | - R Gifford
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - M Stacey
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - D R Woods
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
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20
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Parsons IT, Snape D, O'Hara J, Holdsworth DA, Stacey MJ, Gall N, Chowienczyk P, Wainwright B, Woods DR. Echocardiographic changes following active heat acclimation. J Therm Biol 2020; 93:102705. [PMID: 33077126 PMCID: PMC7467033 DOI: 10.1016/j.jtherbio.2020.102705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 11/26/2022]
Abstract
Heat adaption through acclimatisation or acclimation improves cardiovascular stability by maintaining cardiac output due to compensatory increases in stroke volume. The main aim of this study was to assess whether 2D transthoracic echocardiography (TTE) could be used to confirm differences in resting echocardiographic parameters, before and after active heat acclimation (HA). Thirteen male endurance trained cyclists underwent a resting blinded TTE before and after randomisation to either 5 consecutive daily exertional heat exposures of controlled hyperthermia at 32°C with 70% relative humidity (RH) (HOT) or 5-days of exercise in temperate (21°C with 36% RH) environmental conditions (TEMP). Measures of HA included heart rate, gastrointestinal temperature, skin temperature, sweat loss, total non-urinary fluid loss (TNUFL), plasma volume and participant's ratings of perceived exertion (RPE). Following HA, the HOT group demonstrated increased sweat loss (p = 0.01) and TNUFL (p = 0.01) in comparison to the TEMP group with a significantly decreased RPE (p = 0.01). On TTE, post exposure, there was a significant comparative increase in the HOT group in left ventricular end diastolic volume (p = 0.029), SV (p = 0.009), left atrial volume (p = 0.005), inferior vena cava diameter (p = 0.041), and a significant difference in mean peak diastolic mitral annular velocity (e’) (p = 0.044). Cardiovascular adaptations to HA appear to be predominantly mediated by improvements in increased preload and ventricular compliance. TTE is a useful tool to demonstrate and quantify cardiac HA. There are echocardiographic differences in comparing an isothermic heat acclimation regime to equivalent temperate exercise. Heat acclimation results in an increased LA volume, LVEDV, stroke volume, IVC diameter and LV diastolic function (e’). The increase in LA volume and IVC diameter would suggest an increase in preload secondary to increased plasma volume. The rise in the speed of early LV relaxation (e’) during diastole reflects increased LV compliance or reduced LV stiffness. This gives further insight into the cardiovascular adaptations to heat acclimation.
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Affiliation(s)
- Iain T Parsons
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; School of Cardiovascular Medicine and Sciences, King's College London, UK.
| | - Daniel Snape
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK.
| | - John O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK.
| | - David A Holdsworth
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.
| | - Michael J Stacey
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.
| | - Nick Gall
- School of Cardiovascular Medicine and Sciences, King's College London, UK.
| | - Phil Chowienczyk
- School of Cardiovascular Medicine and Sciences, King's College London, UK.
| | - Barney Wainwright
- Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK.
| | - David R Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK.
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21
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O'Hara JP, Duckworth L, Black A, Woods DR, Mellor A, Boos C, Gallagher L, Tsakirides C, Arjomandkhah NC, Morrison DJ, Preston T, King RFGJ. Fuel Use during Exercise at Altitude in Women with Glucose-Fructose Ingestion. Med Sci Sports Exerc 2020; 51:2586-2594. [PMID: 31206498 DOI: 10.1249/mss.0000000000002072] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE This study compared the coingestion of glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at terrestrial high altitude (HA) versus sea level, in women. METHOD Five women completed two bouts of cycling at the same relative workload (55% Wmax) for 120 min on acute exposure to HA (3375 m) and at sea level (~113 m). In each trial, participants ingested 1.2 g·min of glucose (enriched with C glucose) and 0.6 g·min of fructose (enriched with C fructose) before and every 15 min during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation, and endogenous glucose oxidation derived from liver and muscle glycogen. RESULTS The rates and absolute contribution of exogenous carbohydrate oxidation was significantly lower at HA compared with sea level (effect size [ES] > 0.99, P < 0.024), with the relative exogenous carbohydrate contribution approaching significance (32.6% ± 6.1% vs 36.0% ± 6.1%, ES = 0.56, P = 0.059) during the second hour of exercise. In comparison, no significant differences were observed between HA and sea level for the relative and absolute contributions of liver glucose (3.2% ± 1.2% vs 3.1% ± 0.8%, ES = 0.09, P = 0.635 and 5.1 ± 1.8 vs 5.4 ± 1.7 g, ES = 0.19, P = 0.217), and muscle glycogen (14.4% ± 12.2% vs 15.8% ± 9.3%, ES = 0.11, P = 0.934 and 23.1 ± 19.0 vs 28.7 ± 17.8 g, ES = 0.30, P = 0.367). Furthermore, there was no significant difference in total fat oxidation between HA and sea level (66.3 ± 21.4 vs 59.6 ± 7.7 g, ES = 0.32, P = 0.557). CONCLUSIONS In women, acute exposure to HA reduces the reliance on exogenous carbohydrate oxidation during cycling at the same relative exercise intensity.
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Affiliation(s)
- John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Lauren Duckworth
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Alistair Black
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - David R Woods
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM.,Royal Centre for Defence Medicine, Birmingham, UNITED KINGDOM.,Northumbria NHS Trust and Newcastle Trust, UNITED KINGDOM
| | - Adrian Mellor
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM.,Royal Centre for Defence Medicine, Birmingham, UNITED KINGDOM.,James Cook University Hospital, Middlesborough, UNITED KINGDOM
| | - Christopher Boos
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM.,Department of Cardiology, Poole Hospital, Poole, Dorset, UNITED KINGDOM
| | - Liam Gallagher
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Costas Tsakirides
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Nicola C Arjomandkhah
- School of Social and Health Sciences, Leeds Trinity University, Leeds, UNITED KINGDOM
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, University of Glasgow, East Kilbridge, UNITED KINGDOM
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, University of Glasgow, East Kilbridge, UNITED KINGDOM
| | - Roderick F G J King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
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22
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Shah N, Bye K, Marshall A, Woods DR, O'Hara J, Barlow M, Rimmer J, Boos CJ. The Effects of Apnea Training, Using Voluntary Breath Holds, on High Altitude Acclimation: Breathe-High Altitude Study. High Alt Med Biol 2020; 21:152-159. [DOI: 10.1089/ham.2019.0087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Nishma Shah
- Department of Surgical Sciences, Institute of Sports and Exercise Health, University College, London, United Kingdom
| | - Kyo Bye
- Defence Medical Services, Lichfield, United Kingdom
| | - Anna Marshall
- Department of Surgical Sciences, Institute of Sports and Exercise Health, University College, London, United Kingdom
| | - David R. Woods
- Defence Medical Services, Lichfield, United Kingdom
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
| | - John O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Matthew Barlow
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Jo Rimmer
- Defence Medical Services, Lichfield, United Kingdom
| | - Christopher John Boos
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, United Kingdom
- Department of Postgraduate Medical Education, Bournemouth University, Bournemouth, United Kingdom
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23
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Foster MA, Taylor AE, Hill NE, Bentley C, Bishop J, Gilligan LC, Shaheen F, Bion JF, Fallowfield JL, Woods DR, Bancos I, Midwinter MM, Lord JM, Arlt W. Mapping the Steroid Response to Major Trauma From Injury to Recovery: A Prospective Cohort Study. J Clin Endocrinol Metab 2020; 105:5758226. [PMID: 32101296 PMCID: PMC7043227 DOI: 10.1210/clinem/dgz302] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 01/31/2020] [Indexed: 12/31/2022]
Abstract
CONTEXT Survival rates after severe injury are improving, but complication rates and outcomes are variable. OBJECTIVE This cohort study addressed the lack of longitudinal data on the steroid response to major trauma and during recovery. DESIGN We undertook a prospective, observational cohort study from time of injury to 6 months postinjury at a major UK trauma centre and a military rehabilitation unit, studying patients within 24 hours of major trauma (estimated New Injury Severity Score (NISS) > 15). MAIN OUTCOME MEASURES We measured adrenal and gonadal steroids in serum and 24-hour urine by mass spectrometry, assessed muscle loss by ultrasound and nitrogen excretion, and recorded clinical outcomes (ventilator days, length of hospital stay, opioid use, incidence of organ dysfunction, and sepsis); results were analyzed by generalized mixed-effect linear models. FINDINGS We screened 996 multiple injured adults, approached 106, and recruited 95 eligible patients; 87 survived. We analyzed all male survivors <50 years not treated with steroids (N = 60; median age 27 [interquartile range 24-31] years; median NISS 34 [29-44]). Urinary nitrogen excretion and muscle loss peaked after 1 and 6 weeks, respectively. Serum testosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate decreased immediately after trauma and took 2, 4, and more than 6 months, respectively, to recover; opioid treatment delayed dehydroepiandrosterone recovery in a dose-dependent fashion. Androgens and precursors correlated with SOFA score and probability of sepsis. CONCLUSION The catabolic response to severe injury was accompanied by acute and sustained androgen suppression. Whether androgen supplementation improves health outcomes after major trauma requires further investigation.
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Affiliation(s)
- Mark A Foster
- NIHR-Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Royal Centre for Defence Medicine, Queen Elizabeth Hospital Birmingham, UK
- Correspondence and Reprint Requests: Lt Col Mark Anthony Foster, Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, ICT Centre, Birmingham, B15 2SQ. E-mail:
| | - Angela E Taylor
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Neil E Hill
- Section of Investigative Medicine, Imperial College London, UK
| | - Conor Bentley
- NIHR-Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Royal Centre for Defence Medicine, Queen Elizabeth Hospital Birmingham, UK
| | - Jon Bishop
- NIHR-Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Royal Centre for Defence Medicine, Queen Elizabeth Hospital Birmingham, UK
| | - Lorna C Gilligan
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Fozia Shaheen
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, University of Birmingham, Birmingham, UK
| | - Julian F Bion
- Intensive Care Medicine, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | - David R Woods
- Royal Centre for Defence Medicine, Queen Elizabeth Hospital Birmingham, UK
- Leeds Beckett University, Leeds, UK
| | - Irina Bancos
- Division of Endocrinology, Metabolism and Nutrition, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Mark M Midwinter
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | - Janet M Lord
- NIHR-Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
- NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, UK
| | - Wiebke Arlt
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, University of Birmingham, Birmingham, UK
- NIHR Birmingham Biomedical Research Centre, University Hospitals Birmingham NHS Foundation Trust and University of Birmingham, Birmingham, UK
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Parsons IT, Stacey MJ, Woods DR. Heat Adaptation in Military Personnel: Mitigating Risk, Maximizing Performance. Front Physiol 2019; 10:1485. [PMID: 31920694 PMCID: PMC6928107 DOI: 10.3389/fphys.2019.01485] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022] Open
Abstract
The study of heat adaptation in military personnel offers generalizable insights into a variety of sporting, recreational and occupational populations. Conversely, certain characteristics of military employment have few parallels in civilian life, such as the imperative to achieve mission objectives during deployed operations, the opportunity to undergo training and selection for elite units or the requirement to fulfill essential duties under prolonged thermal stress. In such settings, achieving peak individual performance can be critical to organizational success. Short-notice deployment to a hot operational or training environment, exposure to high intensity exercise and undertaking ceremonial duties during extreme weather may challenge the ability to protect personnel from excessive thermal strain, especially where heat adaptation is incomplete. Graded and progressive acclimatization can reduce morbidity substantially and impact on mortality rates, yet individual variation in adaptation has the potential to undermine empirical approaches. Incapacity under heat stress can present the military with medical, occupational and logistic challenges requiring dynamic risk stratification during initial and subsequent heat stress. Using data from large studies of military personnel observing traditional and more contemporary acclimatization practices, this review article (1) characterizes the physical challenges that military training and deployed operations present (2) considers how heat adaptation has been used to augment military performance under thermal stress and (3) identifies potential solutions to optimize the risk-performance paradigm, including those with broader relevance to other populations exposed to heat stress.
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Affiliation(s)
- Iain T. Parsons
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King’s College London, London, United Kingdom
| | - Michael J. Stacey
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Diabetes and Endocrinology, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - David R. Woods
- Academic Department of Military Medicine, Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Department of Sport and Exercise Endocrinology, Carnegie Research Institute, Leeds Beckett University, Leeds, United Kingdom
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25
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Gifford RM, O'Leary TJ, Double RL, Wardle SL, Wilson K, Boyle LD, Homer NZM, Kirschbaum C, Greeves JP, Woods DR, Reynolds RM. Positive adaptation of HPA axis function in women during 44 weeks of infantry-based military training. Psychoneuroendocrinology 2019; 110:104432. [PMID: 31536944 DOI: 10.1016/j.psyneuen.2019.104432] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Basic military training (BMT) is a useful model of prolonged exposure to multiple stressors. 8-12 week BMT is associated with perturbations in the hypothalamic-pituitary-adrenal (HPA) axis which could predispose recruits to injury and psychological strain. However, characterisations of HPA axis adaptations during BMT have not been comprehensive and most studies included few if any women. METHODS We studied women undertaking an arduous, 44-week BMT programme in the UK. Anxiety, depression and resilience questionnaires, average hair cortisol concentration (HCC), morning and evening saliva cortisol and morning plasma cortisol were assessed at regular intervals throughout. A 1-h dynamic cortisol response to 1 μg adrenocorticotrophic hormone-1-24 was performed during weeks 1 and 29. RESULTS Fifty-three women (aged 24 ± 2.5 years) completed the study. Questionnaires demonstrated increased depression and reduced resilience during training (F 6.93 and F 7.24, respectively, both p < 0.001). HCC increased from 3 months before training to the final 3 months of training (median (IQR) 9.63 (5.38, 16.26) versus 11.56 (6.2, 22.45) pg/mg, p = 0.003). Morning saliva cortisol increased during the first 7 weeks of training (0.44 ± 0.23 versus 0.59 ± 0.24 μg/dl p < 0.001) and decreased thereafter, with no difference between the first and final weeks (0.44 ± 0.23 versus 0.38 ± 0.21 μg/dl, p = 0.2). Evening saliva cortisol did not change. Fasting cortisol decreased during training (beginning, mid and end-training concentrations: 701 ± 134, 671 ± 158 and 561 ± 177 nmol/l, respectively, p < 0.001). Afternoon basal cortisol increased during training while there was a trend towards increased peak stimulated cortisol (177 ± 92 versus 259 ± 13 nmol/l, p = 0.003, and 589 ± 164 versus 656 ± 135, p = 0.058, respectively). DISCUSSION These results suggest a normal stress response in early training was followed quickly by habituation, despite psychological and physical stress evidenced by questionnaire scores and HCC, respectively. There was no evidence of HPA axis maladaptation. These observations are reassuring for women undertaking arduous employment.
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Affiliation(s)
- R M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK; Research & Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - T J O'Leary
- Department of Army Health and Physical Performance Research, Andover, Hampshire, UK
| | - R L Double
- Department of Army Health and Physical Performance Research, Andover, Hampshire, UK
| | - S L Wardle
- Department of Army Health and Physical Performance Research, Andover, Hampshire, UK
| | - K Wilson
- Medical Research Council Centre for Reproductive Health, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - L D Boyle
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - N Z M Homer
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK; Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | | | - J P Greeves
- Department of Army Health and Physical Performance Research, Andover, Hampshire, UK; Norwich Medical School, University of East Anglia, Norwich, UK
| | - D R Woods
- Research & Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK
| | - R M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.
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Gifford RM, O'Leary TJ, Wardle SL, Greeves JP, Anderson RA, Woods DR, Reynolds RM. Hypothalamic-pituitary-gonadal (HPG) axis suppression during basic military training in women despite increased adiposity and insulin resistance. ACTA ACUST UNITED AC 2019. [DOI: 10.1530/endoabs.65.op5.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gifford RM, Boos CJ, Reynolds RM, Woods DR. Recovery time and heart rate variability following extreme endurance exercise in healthy women. Physiol Rep 2019; 6:e13905. [PMID: 30381902 PMCID: PMC6209688 DOI: 10.14814/phy2.13905] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/30/2018] [Accepted: 10/01/2018] [Indexed: 11/24/2022] Open
Abstract
The relationship between autonomic function and recovery following prolonged arduous exercise in women has not been examined. We undertook an exploratory study that aimed to examine the temporal change in linear and nonlinear measures of heart rate variability (HRV) following prolonged arduous exercise in the form of first all‐female (mean age 32.7 ± 3.1 years) team to attempt an unassisted Antarctic traverse. HRV analysis was performed before and 1, 4, and 15 days postexpedition. The traverse was completed in 61 days. There was a significant paired reduction in heart rate, LnLF, LF:HF, DFAα1 between baseline and 15 days postexercise in the same environment. Conversely, RMSSD, LnHF and HFnu, SD1:SD2, and SampEn significantly increased. DFAα2 levels significantly fell from baseline to Day 1 postexercise. In conclusion, we observed a significant latent increase in relative parasympathetic dominance and RR interval irregularity at 15 days post prolonged arduous exercise, versus pre‐exercise baseline, in a group of very fit and healthy adult women.
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Affiliation(s)
- Robert M Gifford
- Centre for Cardiovascular Science, Queen's Medical Research Institute, Edinburgh, Edinburgh.,Defence Medical Services, Lichfield, United Kingdom
| | - Christopher J Boos
- Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, United Kingdom.,Centre for Postgraduate Medical Education, Bournemouth University, Bournemouth, United Kingdom.,Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Rebecca M Reynolds
- Centre for Cardiovascular Science, Queen's Medical Research Institute, Edinburgh, Edinburgh
| | - David R Woods
- Defence Medical Services, Lichfield, United Kingdom.,Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, United Kingdom.,Centre for Postgraduate Medical Education, Bournemouth University, Bournemouth, United Kingdom.,Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom.,Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom.,University of Newcastle, Newcastle Upon Tyne, United Kingdom
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Wardle SL, Double RL, Gifford RM, Wright J, Handford S, Venables MC, Woods DR, Reynolds RM, Greeves JP, O'Leary TJ. Sex Differences In Energy Balance During Arduous Military Training. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561327.11209.7e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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O'Leary TJ, Gifford RM, Double RL, Reynolds RM, Woods DR, Wardle SL, Greeves JP. Skeletal Responses To An All-female Unsupported Antarctic Expedition. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561794.81449.a2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Manderson Koivula FN, Wardle SL, Double RL, Gifford RM, Woods DR, Reynolds RM, Handford S, Wright J, O'Leary TJ, Greeves JP. Sleep Patterns During Arduous Military Training in Men and Women. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561335.43488.5b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Taylor N, Gifford RM, Cobb R, Wardle SL, Jones S, Blackadder-Weinstein J, Hattersley J, Wilson A, Imray C, Greeves JP, Reynolds R, Woods DR. Experience from the selection and nutritional preparation for Expedition ICE MAIDEN: the first successful all-female unassisted Antarctic traverse. BMJ Mil Health 2019; 167:27-32. [PMID: 31097481 DOI: 10.1136/jramc-2019-001175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/13/2019] [Accepted: 04/15/2019] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Expedition ICE MAIDEN (Ex IM) was the first all-female unsupported crossing of Antarctica. We describe the prerequisite selection and training, comparing those who formed the final team with other participants, and discuss how the expedition diet was established. METHODS All women serving in the British Army were invited to participate. Following initial assessments, successful women completed three training/selection ski expeditions. Between expeditions 1 and 2, participants completed 6 months rigorous UK-based training. Weight was measured before and after the 6 months UK-based training, expeditions 2 and 3, and body composition by skinfold before and after expedition 2. Participant feedback, body composition and weight changes were applied to modify the expedition diet and provide weight gain targets prior to Ex IM. RESULTS Following 250 applications, 50 women were assessed and 22, 12 and seven women attended training expeditions 1, 2 and 3, respectively. The final team of six women lost more weight than other participants during UK-based training (mean (SD) change -1.3 (1.5) kg vs -0.5 (1.6) kg, respectively, p=0.046) and during training expedition 2 (-2.8 (0.8) kg vs -1.7 (0.4) kg, respectively, p=0.048), when they also gained more lean mass (+2.1 (0.8) kg vs +0.4 (0.7) kg, respectively, p=0.004). The Ex IM diet provided 5000 kCal/day, comprising approximately 45% carbohydrate, 45% fat and 10% protein. Median (range) weight change between expedition 3 and Ex IM was +8.7 (-1.9 to +14.3) kg. CONCLUSIONS The selected Ex IM team demonstrated favourable training-associated body composition changes. Training-associated weight loss informed the expeditionary diet design.
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Affiliation(s)
- Natalie Taylor
- Academic Department of General Practice, Defence Medical Services Research and Clinical Innovation, Birmingham, UK
| | - R M Gifford
- University/ British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK .,Academic Department of Military Medicine, Defence Medical Services Research and Clinical Innovation, Birmingham, UK
| | - R Cobb
- PND Consulting, Birmingham, UK
| | - S L Wardle
- Army Personnel Research Capability, Army Headquarters, Andover, UK
| | - S Jones
- Antarctic Logistics and Expeditions, Salt Lake City, Utah, USA
| | - J Blackadder-Weinstein
- Academic Department of General Practice, Defence Medical Services Research and Clinical Innovation, Birmingham, UK
| | - J Hattersley
- Human Metabolic Research Unit, Universities of Coventry and Warwickshire NHS Trust and University of Warwick, Warwick, UK
| | - A Wilson
- Human Metabolic Research Unit, Universities of Coventry and Warwickshire NHS Trust and University of Warwick, Warwick, UK
| | - C Imray
- Human Metabolic Research Unit, Universities of Coventry and Warwickshire NHS Trust and University of Warwick, Warwick, UK
| | - J P Greeves
- Army Personnel Research Capability, Army Headquarters, Andover, UK
| | - R Reynolds
- University/ British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - D R Woods
- Academic Department of Military Medicine, Defence Medical Services Research and Clinical Innovation, Birmingham, UK.,Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
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Omassoli J, Hill NE, Woods DR, Delves SK, Fallowfield JL, Brett SJ, Wilson D, Corbett RW, Allsopp AJ, Stacey MJ. Variation in renal responses to exercise in the heat with progressive acclimatisation. J Sci Med Sport 2019; 22:1004-1009. [PMID: 31085130 DOI: 10.1016/j.jsams.2019.04.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/23/2019] [Accepted: 04/27/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To investigate changes in renal status from exercise in the heat with acclimatisation and to evaluate surrogates markers of Acute Kidney Injury. DESIGN Prospective observational cohort study. METHODS 20 male volunteers performed 60 min standardised exercise in the heat, at baseline and on four subsequent occasions during a 23-day acclimatisation regimen. Blood was sampled before and after exercise for serum creatinine, copeptin, interleukin-6, normetanephrine and cortisol. Fractional excretion of sodium was calculated for corresponding urine samples. Ratings of Perceived Exertion were reported every 5 min during exercise. Acute Kidney Injury was defined as serum creatinine rise ≥26.5 μmol L-1 or fall in estimated glomerular filtration rate >25%. Predictive values of each candidate marker for developing Acute Kidney Injury were determined by ROC analysis. RESULTS From baseline to Day 23, serum creatinine did not vary at rest, but showed a significant (P<0.05) reduction post-exercise (120 [102, 139] versus 102 [91, 112] μmol L-1). Acute Kidney Injury was common (26/100 exposures) and occurred most frequently in the unacclimatised state. Log-normalised fractional excretion of sodium showed a significant interaction (exercise by acclimatization day), with post-exercise values tending to rise with acclimatisation. Ratings of Perceived Exertion predicted AKI (AUC 0.76, 95% confidence interval 0.65-0.88), performing at least as well as biochemical markers. CONCLUSIONS Heat acclimatization is associated with reduced markers of renal stress and AKI incidence, perhaps due to improved regional perfusion. Acclimatisation and monitoring Ratings of Perceived Exertion are practical, non-invasive measures that could help to reduce renal injury from exercise in the heat.
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Affiliation(s)
| | - Neil E Hill
- Department of Medicine, Imperial College London, United Kingdom
| | - David R Woods
- Department of Military Medicine, Royal Centre for Defence Medicine, United Kingdom; Carnegie Research Institute, Leeds Beckett University, United Kingdom
| | - Simon K Delves
- Environmental Medicine and Science Division, Institute of Naval Medicine, United Kingdom
| | - Joanne L Fallowfield
- Environmental Medicine and Science Division, Institute of Naval Medicine, United Kingdom
| | - Stephen J Brett
- Department of Surgery and Cancer, Imperial College London, United Kingdom; General intensive Care Unit, Hammersmith Hospital, London, United Kingdom
| | - Duncan Wilson
- Department of Military Medicine, Royal Centre for Defence Medicine, United Kingdom
| | | | - Adrian J Allsopp
- Environmental Medicine and Science Division, Institute of Naval Medicine, United Kingdom
| | - Michael J Stacey
- Department of Military Medicine, Royal Centre for Defence Medicine, United Kingdom; Department of Surgery and Cancer, Imperial College London, United Kingdom.
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Gifford RM, Allerhand M, Woods DR, Reynolds RM. Response to "Letter to the Editors" regarding the article "Risk of heat illness in men and women: A systematic review and meta-analysis". Environ Res 2019; 172:723. [PMID: 30824120 DOI: 10.1016/j.envres.2019.01.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK; Defence Medical Services, Lichfield, UK
| | - Michael Allerhand
- Centre for Statistics, School of Mathematics, University of Edinburgh, Edinburgh, UK
| | - David R Woods
- Defence Medical Services, Lichfield, UK; Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK; University of Newcastle, Newcastle upon Tyne, UK
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK.
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O'Leary TJ, Gifford RM, Double RL, Reynolds RM, Woods DR, Wardle SL, Greeves JP. Skeletal responses to an all-female unassisted Antarctic traverse. Bone 2019; 121:267-276. [PMID: 30735797 DOI: 10.1016/j.bone.2019.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/03/2019] [Accepted: 02/05/2019] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate the skeletal effects of the first all-female trans-Antarctic traverse. METHODS Six women (mean ± SD, age 32 ± 3 years, height 1.72 ± 0.07 m, body mass 72.8 ± 4.0 kg) hauled 80 kg sledges over 1700 km in 61 days from coast-to-coast across the Antarctic. Whole-body areal bone mineral density (aBMD) (dual-energy X-ray absorptiometry) and tibial volumetric BMD (vBMD), geometry, microarchitecture and estimated mechanical properties (high-resolution peripheral quantitative computed tomography) were assessed 39 days before (pre-expedition) and 15 days after the expedition (post-expedition). Serum and plasma markers of bone turnover were assessed pre-expedition, and 4 and 15 days after the expedition. RESULTS There were reductions in trunk (-2.6%), ribs (-5.0%) and spine (-3.4%) aBMD from pre- to post-expedition (all P ≤ 0.046); arms, legs, pelvis and total body aBMD were not different (all P ≥ 0.075). Tibial vBMD, geometry, microarchitecture and estimated mechanical properties at the metaphysis (4% site) and diaphysis (30% site) were not different between pre- and post-expedition (all P ≥ 0.082). Bone-specific alkaline phosphatase was higher 15 days post- than 4 days post-expedition (1.7 μg∙l-1, P = 0.028). Total 25(OH)D decreased from pre- to 4 days post-expedition (-36 nmol∙l-1, P = 0.008). Sclerostin, procollagen 1 N-terminal propeptide, C-telopeptide cross-links of type 1 collagen and adjusted calcium were unchanged (all P ≥ 0.154). CONCLUSION A decline in aBMD of the axial skeleton may be due to indirect and direct effects of prolonged energy deficit. We propose that weight-bearing exercise was protective against the effects of energy deficit on tibial vBMD, geometry, microarchitecture and strength.
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Affiliation(s)
- Thomas J O'Leary
- Army Personnel Research Capability, Army Headquarters, Andover, UK.
| | - Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK; Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.
| | - Rebecca L Double
- Army Personnel Research Capability, Army Headquarters, Andover, UK.
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.
| | - David R Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK; University of Newcastle, Newcastle, UK.
| | - Sophie L Wardle
- Army Personnel Research Capability, Army Headquarters, Andover, UK.
| | - Julie P Greeves
- Army Personnel Research Capability, Army Headquarters, Andover, UK.
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Gifford RM, Todisco T, Stacey M, Fujisawa T, Allerhand M, Woods DR, Reynolds RM. Risk of heat illness in men and women: A systematic review and meta-analysis. Environ Res 2019; 171:24-35. [PMID: 30641370 DOI: 10.1016/j.envres.2018.10.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/15/2018] [Accepted: 10/17/2018] [Indexed: 05/13/2023]
Abstract
BACKGROUND Heat illness (HI) is a growing global concern; its incidence has risen dramatically across the world in recent years. The individual factors whereby elevated core temperature produces HI are not well-understood. Given known physiological differences between men and women pertaining to temperature regulation, we hypothesized that women would be at increased risk of HI than men. OBJECTIVES We aimed to determine the relative risk of HI in women compared with men through an exhaustive literature review and meta-analysis. METHODS We search PubMed and Ovid Medline databases from inception to Apr 2017. Search terms included all permutations of sex and heat illness (including heatstroke and exertional heat illness) with no language restrictions. We included adult or adolescent human data reporting comparable male and female HI rates. One reviewer identified and screened titles and abstracts. Two independent reviewers applied eligibility criteria. Disagreements were resolved with a third reviewer. RESULTS Of 5888 articles identified by searches, 36 were included in the systematic review and 22 in the meta-analysis. The mean (standard deviation) quality score was 3.31(1.25)/5. Overall the rate among women was consistently lower than men across the lifespan. The male: female pooled IRR was 2.28 (p < 0.001, 95% CI: 1.66-3.16). There was modest heterogeneity (between-studies variance (τ2) = 0.02). The rates did not differ significantly when corrected for severity or occupation. DISCUSSION The rate of HI was significantly increased in men compared with women. Risk for HI might be conferred by psychological and behavioral factors rather than physiological ones. Further research is required to delineate which groups are at greatest risk, leading to the development of mitigation strategies against HI. OTHER No funding was received. The authors acknowledge the support of the UK Women in Ground Close Combat Review. The Study was registered with PROSPREO CRD42017064739.
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Affiliation(s)
- Robert M Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; Department of Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - T Todisco
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - M Stacey
- Department of Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - T Fujisawa
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - M Allerhand
- Centre for Statistics, School of Mathematics, University of Edinburgh, Edinburgh, UK
| | - D R Woods
- Department of Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK; University of Newcastle, Newcastle upon Tyne, UK
| | - R M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK.
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Hattersley J, Wilson AJ, Gifford RM, Cobb R, Thake CD, Reynolds RM, Woods DR, Imray CHE. Pre- to postexpedition changes in the energy usage of women undertaking sustained expeditionary polar travel. J Appl Physiol (1985) 2019; 126:681-690. [DOI: 10.1152/japplphysiol.00792.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This paper reports the metabolic energy changes in six women who made the first unsupported traverse of Antarctica, covering a distance of 1,700 km in 61 days, hauling sledges weighing up to 80 kg. Pre- and postexpedition, measurements of energy expenditure and substrate utilization were made on all six members of the expedition over a 36-h period in a whole body calorimeter. During the study, subjects were fed an isocaloric diet: 50% carbohydrate, 35% fat, and 15% protein. The experimental protocol contained pre- and postexpedition measurement, including periods of sleep, rest, and three periods of standardized stepping exercise at 80, 100, and 120 steps/min. A median (interquartile range) decrease in the lean and fat weight of the subjects of 1.4 (1.0) and 4.4 (1.8) kg, respectively (P < 0.05) was found, using air-displacement plethysmography. No statistically significant difference was found between pre- and postexpedition values for sleeping or resting metabolic rate, nor for diet-induced thermogenesis. A statistically significant difference was found in energy expenditure between the pre- and postexpedition values for exercise at 100 [4.7 (0.23) vs. 4.4 (0.29), P < 0.05] and 120 [5.7 (0.46) vs. 5.5 (0.43), P < 0.05] steps/min; a difference that disappeared when the metabolic rate values were normalized to body weight. The group was well matched for the measures studied. Whereas a physiological change in weight was seen, the lack of change in metabolic rate measures supports a view that women appropriately nourished and well prepared can undertake polar expeditions with a minimal metabolic energy consequence. NEW & NOTEWORTHY This is the first study on the metabolic energy consequences for women undertaking expeditionary polar travel. The results show that participant selection gave a “well-matched” group, particularly during exercise. Notwithstanding this, individual differences were observed and explored. The results show that appropriately selected, trained, and nourished women can undertake such expeditions with no change in their metabolic energy requirements during rest or while undertaking moderate exercise over a sustained period of time.
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Affiliation(s)
- John Hattersley
- Coventry National Institute for Health Research, Clinical Research Facility, Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
- School of Engineering, University of Warwick, Coventry, United Kingdom
| | - Adrian J. Wilson
- Coventry National Institute for Health Research, Clinical Research Facility, Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
- Department of Physics, University of Warwick, Coventry, United Kingdom
| | - Robert M. Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
| | - Rin Cobb
- Performance, Nutrition and Dietetic Consulting, Birmingham, United Kingdom
| | - C. Doug Thake
- Faculty of Health and Life Sciences, Coventry University, Coventry, United Kingdom
| | - Rebecca M. Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - David R. Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Northumbria and Newcastle National Health Service Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Christopher H. E. Imray
- Coventry National Institute for Health Research, Clinical Research Facility, Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
- Faculty of Health and Life Sciences, Coventry University, Coventry, United Kingdom
- Department of Vascular and Renal Transplant Surgery, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
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Gifford RM, Howie F, Wilson K, Johnston N, Todisco T, Crane M, Greeves JP, Skorupskaite K, Woods DR, Reynolds RM, Anderson RA. Confirmation of ovulation from urinary progesterone analysis: assessment of two automated assay platforms. Sci Rep 2018; 8:17621. [PMID: 30514870 PMCID: PMC6279762 DOI: 10.1038/s41598-018-36051-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 11/15/2018] [Indexed: 11/09/2022] Open
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Stacey MJ, Woods DR, Brett SJ, Britland SE, Fallowfield JL, Allsopp AJ, Delves SK. Heat acclimatization blunts copeptin responses to hypertonicity from dehydrating exercise in humans. Physiol Rep 2018; 6:e13851. [PMID: 30221840 PMCID: PMC6139708 DOI: 10.14814/phy2.13851] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 08/04/2018] [Accepted: 08/10/2018] [Indexed: 11/24/2022] Open
Abstract
Acclimatization favors greater extracellular tonicity from lower sweat sodium, yet hyperosmolality may impair thermoregulation during heat stress. Enhanced secretion or action of vasopressin could mitigate this through increased free water retention. Aims were to determine responses of the vasopressin surrogate copeptin to dehydrating exercise and investigate its relationships with tonicity during short and long-term acclimatization. Twenty-three participants completed a structured exercise programme following arrival from a temperate to a hot climate. A Heat Tolerance Test (HTT) was conducted on Day-2, 6, 9 and 23, consisting of 60-min block-stepping at 50% VO2 peak, with no fluid intake. Resting sweat [Na+ ] was measured by iontophoresis. Changes in body mass (sweat loss), core temperature, heart rate, osmolality (serum and urine) and copeptin and aldosterone (plasma) were measured with each Test. From Day 2 to Day 23, sweat [Na+ ] decreased significantly (adjusted P < 0.05) and core temperature and heart rate fell. Over the same interval, HTT-associated excursions were increased for serum osmolality (5 [-1, 9] vs. 9 [5, 12] mosm·kg-1 ), did not differ for copeptin (9.6 [6.0, 15.0] vs. 7.9 [4.3, 14.7] pmol·L-1 ) and were reduced for aldosterone (602 [415, 946] vs. 347 [263, 537] pmol·L-1 ). Urine osmolality was unchanging and related consistently to copeptin at end-exercise, whereas the association between copeptin and serum osmolality was right-shifted (P = 0.0109) with acclimatization. Unchanging urine:serum osmolality argued against increased renal action of vasopressin. In conclusion, where exercise in the heat is performed without fluid replacement, heat acclimatization does not appear to enhance AVP-mediated free water retention in humans.
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Affiliation(s)
- Michael J. Stacey
- Department of Surgery and CancerImperial College LondonLondonUnited Kingdom
- Department of Military MedicineRoyal Centre for Defence MedicineBirminghamUnited Kingdom
| | - David R. Woods
- Department of Surgery and CancerImperial College LondonLondonUnited Kingdom
- Carnegie Research InstituteLeeds Beckett UniversityLeedsUnited Kingdom
| | - Stephen J. Brett
- Department of Surgery and CancerImperial College LondonLondonUnited Kingdom
| | | | | | | | - Simon K. Delves
- Institute of Naval MedicineAlverstokeHampshireUnited Kingdom
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Boos CJ, Bass M, O’Hara JP, Vincent E, Mellor A, Sevier L, Abdul-Razakq H, Cooke M, Barlow M, Woods DR. The relationship between anxiety and acute mountain sickness. PLoS One 2018; 13:e0197147. [PMID: 29927953 PMCID: PMC6013200 DOI: 10.1371/journal.pone.0197147] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 04/28/2018] [Indexed: 01/04/2023] Open
Abstract
Introduction Whilst the link between physical factors and risk of high altitude (HA)-related illness and acute mountain sickness (AMS) have been extensively explored, the influence of psychological factors has been less well examined. In this study we aimed to investigate the relationship between ‘anxiety and AMS risk during a progressive ascent to very HA. Methods Eighty health adults were assessed at baseline (848m) and over 9 consecutive altitudes during a progressive trek to 5140m. HA-related symptoms (Lake Louise [LLS] and AMS-C Scores) and state anxiety (State-Trait-Anxiety-Score [STAI Y-1]) were examined at each altitude with trait anxiety (STAI Y-2) at baseline. Results The average age was 32.1 ± 8.3 years (67.5% men). STAI Y-1 scores fell from 848m to 3619m, before increasing to above baseline scores (848m) at ≥4072m (p = 0.01). STAI Y-1 scores correlated with LLS (r = 0.31; 0.24–0.3; P<0.0001) and AMS-C Scores (r = 0.29; 0.22–0.35; P<0.0001). There was significant main effect for sex (higher STAI Y-1 scores in women) and altitude with no sex-x-altitude interaction on STAI Y-1 Scores. Independent predictors of significant state anxiety included female sex, lower age, higher heart rate and increasing LLS and AMS-C scores (p<0.0001). A total of 38/80 subjects (47.5%) developed AMS which was mild in 20 (25%) and severe in 18 (22.5%). Baseline STAI Y-2 scores were an independent predictor of future severe AMS (B = 1.13; 1.009–1.28; p = 0.04; r2 = 0.23) and STAI Y-1 scores at HA independently predicted AMS and its severity. Conclusion Trait anxiety at low altitude was an independent predictor of future severe AMS development at HA. State anxiety at HA was independently associated with AMS and its severity.
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Affiliation(s)
- Christopher J. Boos
- Department of Cardiology, Poole Hospital NHS Foundation trust, Poole, United Kingdom
- Department of Postgraduate Medical Education, Bournemouth University, Bournemouth, United Kingdom
- Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- * E-mail:
| | - Malcolm Bass
- Consultant Clinical Psychologist, Tees Esk and Wear Valleys NHS Trust, Middlesbrough, United Kingdom
| | - John P. O’Hara
- Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Emma Vincent
- Defence Medical Services, Lichfield, United Kingdom
| | - Adrian Mellor
- Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Consultant Clinical Psychologist, Tees Esk and Wear Valleys NHS Trust, Middlesbrough, United Kingdom
- Defence Medical Services, Lichfield, United Kingdom
- James Cook University Hospital, Middlesbrough, United Kingdom
| | - Luke Sevier
- Department of Cardiology, Poole Hospital NHS Foundation trust, Poole, United Kingdom
| | - Humayra Abdul-Razakq
- Department of Cardiology, Poole Hospital NHS Foundation trust, Poole, United Kingdom
| | - Mark Cooke
- Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Matt Barlow
- Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - David R. Woods
- Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Consultant Clinical Psychologist, Tees Esk and Wear Valleys NHS Trust, Middlesbrough, United Kingdom
- Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
- University of Newcastle, Newcastle upon Tyne, United Kingdom
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Boos CJ, Bye K, Sevier L, Bakker-Dyos J, Woods DR, Sullivan M, Quinlan T, Mellor A. High Altitude Affects Nocturnal Non-linear Heart Rate Variability: PATCH-HA Study. Front Physiol 2018; 9:390. [PMID: 29713290 PMCID: PMC5911497 DOI: 10.3389/fphys.2018.00390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/28/2018] [Indexed: 01/23/2023] Open
Abstract
Background: High altitude (HA) exposure can lead to changes in resting heart rate variability (HRV), which may be linked to acute mountain sickness (AMS) development. Compared with traditional HRV measures, non-linear HRV appears to offer incremental and prognostic data, yet its utility and relationship to AMS have been barely examined at HA. This study sought to examine this relationship at terrestrial HA. Methods: Sixteen healthy British military servicemen were studied at baseline (800 m, first night) and over eight consecutive nights, at a sleeping altitude of up to 3600 m. A disposable cardiac patch monitor was used, to record the nocturnal cardiac inter-beat interval data, over 1 h (0200-0300 h), for offline HRV assessment. Non-linear HRV measures included Sample entropy (SampEn), the short (α1, 4-12 beats) and long-term (α2, 13-64 beats) detrend fluctuation analysis slope and the correlation dimension (D2). The maximal rating of perceived exertion (RPE), during daily exercise, was assessed using the Borg 6-20 RPE scale. Results: All subjects completed the HA exposure. The average age of included subjects was 31.4 ± 8.1 years. HA led to a significant fall in SpO2 and increase in heart rate, LLS and RPE. There were no significant changes in the ECG-derived respiratory rate or in any of the time domain measures of HRV during sleep. The only notable changes in frequency domain measures of HRV were an increase in LF and fall in HFnu power at the highest altitude. Conversely, SampEn, SD1/SD2 and D2 all fell, whereas α1 and α2 increased (p < 0.05). RPE inversely correlated with SD1/SD2 (r = -0.31; p = 0.002), SampEn (r = -0.22; p = 0.03), HFnu (r = -0.27; p = 0.007) and positively correlated with LF (r = 0.24; p = 0.02), LF/HF (r = 0.24; p = 0.02), α1 (r = 0.32; p = 0.002) and α2 (r = 0.21; p = 0.04). AMS occurred in 7/16 subjects (43.8%) and was very mild in 85.7% of cases. HRV failed to predict AMS. Conclusion: Non-linear HRV is more sensitive to the effects of HA than time and frequency domain indices. HA leads to a compensatory decrease in nocturnal HRV and complexity, which is influenced by the RPE measured at the end of the previous day. HRV failed to predict AMS development.
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Affiliation(s)
- Christopher J Boos
- Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, United Kingdom.,Centre of Postgraduate Medical Research and Education, Bournemouth University, Bournemouth, United Kingdom.,Research Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Kyo Bye
- The Defence Medical Services, Lichfield, United Kingdom
| | - Luke Sevier
- Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, United Kingdom
| | - Josh Bakker-Dyos
- Research Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - David R Woods
- Research Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom.,The Defence Medical Services, Lichfield, United Kingdom.,Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.,Department of Academic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | | | - Adrian Mellor
- The Defence Medical Services, Lichfield, United Kingdom.,James Cook University Hospital, Middlesbrough, United Kingdom
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O'Hara JP, Woods DR, Mellor A, Boos C, Gallagher L, Tsakirides C, Arjomandkhah NC, Holdsworth DA, Cooke CB, Morrison DJ, Preston T, King RF. A comparison of substrate oxidation during prolonged exercise in men at terrestrial altitude and normobaric normoxia following the coingestion of 13C glucose and 13C fructose. Physiol Rep 2017; 5:5/1/e13101. [PMID: 28082428 PMCID: PMC5256160 DOI: 10.14814/phy2.13101] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 11/30/2016] [Accepted: 11/29/2016] [Indexed: 01/14/2023] Open
Abstract
This study compared the effects of coingesting glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at altitude and sea level, in men. Seven male British military personnel completed two bouts of cycling at the same relative workload (55% Wmax) for 120 min on acute exposure to altitude (3375 m) and at sea level (~113 m). In each trial, participants ingested 1.2 g·min−1 of glucose (enriched with 13C glucose) and 0.6 g·min−1 of fructose (enriched with 13C fructose) directly before and every 15 min during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation, and endogenous glucose oxidation derived from liver and muscle glycogen. Total carbohydrate oxidation during the exercise period was lower at altitude (157.7 ± 56.3 g) than sea level (286.5 ± 56.2 g, P = 0.006, ES = 2.28), whereas fat oxidation was higher at altitude (75.5 ± 26.8 g) than sea level (42.5 ± 21.3 g, P = 0.024, ES = 1.23). Peak exogenous carbohydrate oxidation was lower at altitude (1.13 ± 0.2 g·min−1) than sea level (1.42 ± 0.16 g·min−1, P = 0.034, ES = 1.33). There were no differences in rates, or absolute and relative contributions of plasma or liver glucose oxidation between conditions during the second hour of exercise. However, absolute and relative contributions of muscle glycogen during the second hour were lower at altitude (29.3 ± 28.9 g, 16.6 ± 15.2%) than sea level (78.7 ± 5.2 g (P = 0.008, ES = 1.71), 37.7 ± 13.0% (P = 0.016, ES = 1.45). Acute exposure to altitude reduces the reliance on muscle glycogen and increases fat oxidation during prolonged cycling in men compared with sea level.
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Affiliation(s)
- John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - David R Woods
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom.,Royal Centre for Defence Medicine, Birmingham, United Kingdom.,Northumbria NHS Trust and Newcastle Trust, Newcastle, United Kingdom
| | - Adrian Mellor
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom.,Royal Centre for Defence Medicine, Birmingham, United Kingdom.,James Cook University Hospital, Middlesborough, United Kingdom
| | - Christopher Boos
- Department of Cardiology, Poole Hospital, Poole, Dorset, United Kingdom
| | - Liam Gallagher
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Costas Tsakirides
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Nicola C Arjomandkhah
- School of Social and Health Sciences, Leeds Trinity University, Leeds, United Kingdom
| | | | - Carlton B Cooke
- School of Social and Health Sciences, Leeds Trinity University, Leeds, United Kingdom
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, Glasgow, United Kingdom
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, Glasgow, United Kingdom
| | - Roderick Fgj King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
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Stacey MJ, Delves SK, Britland SE, Allsopp AJ, Brett SJ, Fallowfield JL, Woods DR. Copeptin reflects physiological strain during thermal stress. Eur J Appl Physiol 2017; 118:75-84. [PMID: 29075863 PMCID: PMC5754412 DOI: 10.1007/s00421-017-3740-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 10/08/2017] [Indexed: 11/22/2022]
Abstract
Purpose To prevent heat-related illnesses, guidelines recommend limiting core body temperature (Tc) ≤ 38 °C during thermal stress. Copeptin, a surrogate for arginine vasopressin secretion, could provide useful information about fluid balance, thermal strain and health risks. It was hypothesised that plasma copeptin would rise with dehydration from occupational heat stress, concurrent with sympathoadrenal activation and reduced glomerular filtration, and that these changes would reflect Tc responses. Methods Volunteers (n = 15) were recruited from a British Army unit deployed to East Africa. During a simulated combat assault (3.5 h, final ambient temperature 27 °C), Tc was recorded by radiotelemetry to differentiate volunteers with maximum Tc > 38 °C versus ≤ 38 °C. Blood was sampled beforehand and afterwards, for measurement of copeptin, cortisol, free normetanephrine, osmolality and creatinine. Results There was a significant (P < 0.05) rise in copeptin from pre- to post-assault (10.0 ± 6.3 vs. 16.7 ± 9.6 pmol L−1, P < 0.001). Although osmolality did not increase, copeptin correlated strongly with osmolality after the exposure (r = 0.70, P = 0.004). In volunteers with maximum Tc > 38 °C (n = 8) vs ≤ 38 °C (n = 7) there were significantly greater elevations in copeptin (10.4 vs. 2.4 pmol L−1) and creatinine (10 vs. 2 μmol L−1), but no differences in cortisol, free normetanephrine or osmolality. Conclusions Changes in copeptin reflected Tc response more closely than sympathoadrenal markers or osmolality. Dynamic relationships with tonicity and kidney function may help to explain this finding. As a surrogate for integrated physiological strain during work in a field environment, copeptin assay could inform future measures to prevent heat-related illnesses.
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Affiliation(s)
- Michael John Stacey
- Department of Surgery and Cancer, Imperial College London, Care of General Intensive Care Unit, Hammersmith Hospital Campus, Du Cane Road, London, W12 0HS, UK. .,Department of Military Medicine, Royal Centre for Defence Medicine, ICT Building, Birmingham Research Park, Vincent Drive, Edgbaston, Birmingham, B15 2SQ, UK.
| | - Simon K Delves
- Institute of Naval Medicine, Alverstoke, Hampshire, PO12 2DL, UK
| | | | - Adrian J Allsopp
- Institute of Naval Medicine, Alverstoke, Hampshire, PO12 2DL, UK
| | - Stephen J Brett
- Department of Surgery and Cancer, Imperial College London, Care of General Intensive Care Unit, Hammersmith Hospital Campus, Du Cane Road, London, W12 0HS, UK
| | | | - David R Woods
- Department of Military Medicine, Royal Centre for Defence Medicine, ICT Building, Birmingham Research Park, Vincent Drive, Edgbaston, Birmingham, B15 2SQ, UK.,Carnegie Research Institute, Leeds Beckett University, Leeds, LS6 3QS, UK
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Boos CJ, Holdsworth D, Woods DR, O'Hara JP, Brooks N, Macconnachie L, Bakker-Dyos J, Paisey JR, Mellor A. 18Assessment of cardiac arrhythmias at extreme high altitude using an implantable cardiac monitor: REVEAL HA Study. Europace 2017. [DOI: 10.1093/europace/eux283.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Boos CJ, Vincent E, Mellor A, Woods DR, New C, Cruttenden R, Barlow M, Cooke M, Deighton K, Scott P, Clarke S, O'Hara J. The effect of high altitude on central blood pressure and arterial stiffness. J Hum Hypertens 2017; 31:715-719. [PMID: 28540933 DOI: 10.1038/jhh.2017.40] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/05/2017] [Accepted: 01/17/2017] [Indexed: 12/31/2022]
Abstract
Central arterial systolic blood pressure (SBP) and arterial stiffness are known to be better predictors of adverse cardiovascular outcomes than brachial SBP. The effect of progressive high altitude (HA) on these parameters has not been examined. Ninety healthy adults were included. Central BP and the augmentation index (AI) were measured at the level of the brachial artery (Uscom BP+ device) at <200 m and at 3619, 4600 and 5140 m. The average age of the subjects (70% men) were 32.2±8.7 years. Compared with central arterial pressures, brachial SBP (+8.1±6.4 mm Hg; P<0.0001) and pulse pressure (+10.9±6.6 mm Hg; P<0.0001) were significantly higher and brachial diastolic BP was lower (-2.8±1.6 mm Hg; P<0.0001). Compared with <200 m, HA led to a significant increase in brachial and central SBP. Central SBP correlated with AI (r=0.50; 95% confidence interval (CI): 0.41-0.58; P<0.0001) and age (r=0.32; 95% CI: 21-0.41; P<0.001). AI positively correlated with age (r=0.39; P<0.001) and inversely with subject height (r=-0.22; P<0.0001), weight (r=-0.19; P=0.006) and heart rate (r=-0.49; P<0.0001). There was no relationship between acute mountain sickness scores (Lake Louis Scoring System (LLS)) and AI or central BP. The independent predictors of central SBP were male sex (coefficient, t=4.7; P<0.0001), age (t=3.6; P=0.004) and AI (t=7.5; P<0.0001; overall r2=0.40; P<0.0001). Subject height (t=2.4; P=0.02), age (7.4; P<0.0001) and heart rate (t=11.4; P<0.0001) were the only independent predictors of AI (overall r2=0.43; P<0.0001). Central BP and AI significantly increase at HA. This rise was influenced by subject-related factors and heart rate but not independently by altitude, LLS or SpO2.
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Affiliation(s)
- C J Boos
- Department of Cardiology, Poole Hospital NHS Foundation Trust, Leeds Beckett and Bournemouth Universities, Poole, UK.,Department of Postgraduate Medical Education, Bournemouth University, Bournemouth, UK.,Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - E Vincent
- Defence Medical Services, Lichfield, UK
| | - A Mellor
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.,Defence Medical Services, Lichfield, UK.,James Cook University Hospital, Middlesbrough, UK
| | - D R Woods
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.,Defence Medical Services, Lichfield, UK.,Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle upon Tyne, UK.,University of Newcastle, Newcastle upon Tyne, UK
| | - C New
- Defence Medical Services, Lichfield, UK
| | | | - M Barlow
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - M Cooke
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - K Deighton
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - P Scott
- Defence Medical Services, Lichfield, UK
| | - S Clarke
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - J O'Hara
- Research Institute, For Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
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Gifford RM, Reynolds RM, Greeves J, Anderson RA, Woods DR. Reproductive dysfunction and associated pathology in women undergoing military training. J ROY ARMY MED CORPS 2017; 163:301-310. [DOI: 10.1136/jramc-2016-000727] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/15/2016] [Accepted: 01/27/2017] [Indexed: 01/07/2023]
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Woods DR, Hill NE, Neely RDG, Talks KL, Heggie A, Quinton R. Hematopoiesis Shows Closer Correlation with Calculated Free Testosterone in Men than Total Testosterone. J Appl Lab Med 2017; 1:441-444. [PMID: 33636807 DOI: 10.1373/jalm.2016.022012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/25/2016] [Indexed: 11/06/2022]
Affiliation(s)
- David R Woods
- Department of Endocrinology and Diabetes, Northumbria NHS Trust, North Shields, UK.,Royal Centre for Defence Medicine, Birmingham, UK.,Carnegie Research Institute, Leeds Beckett University, Leeds, UK.,Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle-upon-Tyne, UK
| | - Neil E Hill
- Royal Centre for Defence Medicine, Birmingham, UK
| | - R Dermot G Neely
- Department of Clinical Biochemistry, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle-upon-Tyne, UK
| | - Kate L Talks
- Department of Haematology, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle-upon-Tyne, UK
| | - Alison Heggie
- Institute of Cellular Medicine, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne, UK
| | - Richard Quinton
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle-upon-Tyne, UK.,Institute of Genetic Medicine, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne, UK
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Sanders J, Harris J, Cooper J, Gohlke P, Humphries SE, Montgomery H, Woods DR. Lack of change in serum angiotensin-converting enzyme activity during the menstrual cycle. J Renin Angiotensin Aldosterone Syst 2016; 7:231-5. [PMID: 17318793 DOI: 10.3317/jraas.2006.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Introduction. The Deletion (D) rather than Insertion (I) variant of the angiotensin-converting enzyme (ACE) gene is associated with higher circulating ACE activity. Meanwhile, coronary risk rises with the menstrual nadir in oestrogen levels, exogenous oestrogen reduces serum ACE activity (with a greater reduction the higher the baseline ACE activity), and pharmacological reduction in ACE activity is cardioprotective. Alterations in coronary risk associated with the menstrual cycle may thus be mediated through (genotype-dependent) changes in ACE activity. We have examined this hypothesis. Materials and methods. Twenty-three healthy female subjects (12 II, 11 DD genotype) were studied. None were taking oral contraceptive agents. Blood was assayed for oestrogen, follicle stimulating hormone (FSH), luteinising hormone (LH), progesterone and ACE activity every three days throughout their menstrual cycle. Results ACE activity was unrelated to oestrogen, FSH or LH during the menstrual cycle, irrespective of ACE genotype. Conclusions. The increase in myocardial ischaemia during low oestrogen phases of the menstrual cycle does not appear mediated through a fall in serum ACE activity.
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Affiliation(s)
- Julie Sanders
- Rayne Institute, UCL Centre for Cardiovascular Genetics, 5 University Street, London, UK
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Shannon O, Barlow M, Duckworth L, Woods DR, Barker T, Grindrod A, Griffiths A, O'Hara JP. The Reliability of a Pre-Loaded Treadmill Time-Trial in Moderate Normobaric Hypoxia. Int J Sports Med 2016; 37:825-30. [PMID: 27337430 DOI: 10.1055/s-0042-108651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The purpose of this study was to assess the reliability of a pre-loaded 1 500-m treadmill time trial, conducted in moderate normobaric hypoxia. 8 trained runners/triathletes (24±3 years, 73.2±8.1 kg, 182.5±6.5 cm, altitude specific V˙O2max: 52.9±5.5 ml·kg(-1)·min(-1)) completed 3 trials (the first as a familiarisation), involving 2, 15-min running bouts at 45% and 65% V˙O2max, respectively, and a 1 500-m time trial in moderate normobaric hypoxia equivalent to a simulated altitude of 2 500 m (FiO2~15%). Heart rate, arterial oxygen saturation, skeletal muscle and cerebral tissue oxygenation (StO2), expired gas ( V˙O2 and V˙CO2), and ratings of perceived exertion were monitored. Running performance (Trial 1: 352.7±40; Trial 2: 353.9±38.2 s) demonstrated a low CV (0.9%) and high ICC (1). All physiological variables demonstrated a global CV≤4.2%, and ICC≥0.87, with the exception of muscle (CV 10.4%; ICC 0.70) and cerebral (CV 4.1%; ICC 0.82) StO2. These data demonstrate good reliability of the majority of physiological variables and indicate that a pre-loaded 1 500-m time trial conducted in moderate normobaric hypoxia is a highly reliable test of performance.
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Affiliation(s)
- O Shannon
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - M Barlow
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - L Duckworth
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - D R Woods
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - T Barker
- Department of Vascular Surgery, Royal Stoke University Hospital, Newcastle Road, Stoke on Trent, United Kingdom of Great Britain and Northern Ireland
| | - A Grindrod
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - A Griffiths
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
| | - J P O'Hara
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Carnegie Faculty, Headingley Campus, Headingley, Leeds, United Kingdom of Great Britain and Northern Ireland
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Lois KB, Santhakumar A, Vaikkakara S, Mathew S, Long A, Johnson SJ, Peaston R, Neely RDG, Richardson DL, Graham J, Lennard TWJ, Bliss R, Miller M, Ball SG, Pearce SHS, Woods DR, Quinton R. Phaeochromocytoma and ACTH-dependent cushing's syndrome: tumour crf secretion can mimic pituitary cushing's disease. Clin Endocrinol (Oxf) 2016; 84:177-184. [PMID: 26433209 DOI: 10.1111/cen.12960] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/28/2015] [Accepted: 09/26/2015] [Indexed: 12/01/2022]
Abstract
INTRODUCTION 10% of corticotrophin (ACTH)-dependent Cushing's syndrome arises from secretion by extrapituitary tumours, with phaeochromocytoma implicated in a few cases. Ectopic secretion by phaeochromocytoma of corticotropin-releasing hormone (CRF), with secondary corticotroph hyperplasia, is even rarer, with only five cases in the literature hitherto. However, such cases may be classified as 'ectopic ACTH' due to incomplete verification. CLINICAL CASES We describe three patients with phaeochromocytoma and ACTH-dependent Cushing's syndrome in whom biochemical cure was achieved following unilateral adrenalectomy. Although unable to access a validated CRF assay within the timeframe for sample storage, we nevertheless inferred CRF secretion in 2 of 3 cases by tumour immunostaining (positive for CRF; negative for ACTH), supported in one case by pre-operative inferior petrosal sinus sampling (IPSS) indicative of pituitary ACTH source. Both cases were characterized by rapid postoperative wean off glucocorticoids, presumed to reflect the pituitary stimulatory-effect of CRF outweighing central negative feedback inhibition by hypercortisolaemia. By contrast, the tumour excised in a third case exhibited positive immunostaining for ACTH - negative for CRF - and postoperative recovery of hypothalamic-pituitary-adrenal axis took significantly longer. DISCUSSION Ectopic CRF production is biochemically indistinguishable from ectopic ACTH secretion, except that IPSS mimics pituitary Cushing's disease and cortisol dynamics may normalize rapidly postadrenalectomy. CRF secretion can be inferred through tumour immunohistochemistry, even if no CRF assay is available. Unrecognized phaeochromocytoma ACTH secretion may underpin some cases of cardiovascular collapse postadrenalectomy through acute hypocortisolaemia. Despite advances in phaeochromocytoma genetics since previous reports, we were unable to identify somatic DNA defects associated with either ACTH or CRF secretion.
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Affiliation(s)
- Konstantinos B Lois
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Anjali Santhakumar
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Suresh Vaikkakara
- Department of Endocrinology, Sri Venkateswara Institute of Medical Sciences, Tirupati (MP), India
| | - Sajjan Mathew
- Department of Surgery, Oman Health Services, Sohar Hospital, Muscat, Oman
| | - Anna Long
- Department of Cellular Pathology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Sarah J Johnson
- Department of Cellular Pathology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Rovert Peaston
- Department of Clinical Biochemistry, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - R Dermot G Neely
- Department of Clinical Biochemistry, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - David L Richardson
- Department of Radiology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - James Graham
- Department of Radiology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Thomas W J Lennard
- Department of Endocrine Surgery, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
- Newcastle Bioscience, University of Newcastle-upon-Tyne, Newcastle Upon Tyne, UK
| | - Richard Bliss
- Department of Endocrine Surgery, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Margaret Miller
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Stephen G Ball
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
- Newcastle Bioscience, University of Newcastle-upon-Tyne, Newcastle Upon Tyne, UK
| | - Simon H S Pearce
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
- Newcastle Bioscience, University of Newcastle-upon-Tyne, Newcastle Upon Tyne, UK
| | - David R Woods
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
- Royal Centre for Defence Medicine, Birmingham, UK
- Department of Endocrinology & Diabetes, Northumbria NHS Trust, UK
- Carnegie Research Institute, Leeds Beckett University, UK
| | - Richard Quinton
- Department of Endocrinology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
- Newcastle Bioscience, University of Newcastle-upon-Tyne, Newcastle Upon Tyne, UK
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Boos CJ, Woods DR, Varias A, Biscocho S, Heseltine P, Mellor AJ. High Altitude and Acute Mountain Sickness and Changes in Circulating Endothelin-1, Interleukin-6, and Interleukin-17a. High Alt Med Biol 2015; 17:25-31. [PMID: 26680502 DOI: 10.1089/ham.2015.0098] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Hypoxia induces an inflammatory response, which is enhanced by exercise. High altitude (HA) leads to endothelial activation and may be proinflammatory. The relationship between endothelial activation, inflammation, and acute mountain sickness (AMS) and its severity has never been examined. METHODS Forty-eight trekkers were studied during a progressive trek at 3833, 4450, and 5129 m at rest postascent (exercise), and then again at rest 24 hours later. Twenty of the subjects were also tested at rest pre- and postexercise at sea level (SL) at 6 weeks preascent. We examined plasma levels of the interleukin 6 (IL-6), 17a (IL-17a), and endothelin-1 (ET-1) along with oxygen saturation (SpO2) and Lake Louise scores (LLS). RESULTS ET-1 (5.7 ± 2.1 vs. 4.3 ± 1.9 pg/mL; p < 0.001), IL-6 (3.3 ± 3.3 vs. 2.4 ± 2.3 pg/mL; p = 0.007), and IL-17a (1.3 ± 3.0 vs. 0.46 ± 0.4 pg/mL; p < 0.001) were all overall significantly higher at HA versus SL. There was a paired increase in ET-1 and IL-6 with exercise versus rest at SL, 3833, 4450, and 5129 m (p < 0.05). There was a negative correlation between LLS and SpO2 (r = -0.32; 95% confidence interval [CI] -0.21 to -0.42; p < 0.001) and a positive correlation between LLS and IL-6 (r = 0.16; 0.0-0.27; p = 0.007) and ET-1 levels (r = 0.29; 0.18-0.39; p < 0.001. Altitude, ET-1, IL-6, and SpO2 were all univariate predictors of AMS. On multivariate analysis, ET-1 (p = 0.002) and reducing SpO2 (p = 0.02) remained as the only independent predictors (overall r(2) = 0.16; p < 0.001) of AMS. ET-1 (p = 03) and SpO2 were (p = 0.01) also independent predictors of severe AMS (overall r(2) = 0.19; p < 0.001). CONCLUSIONS HA leads to endothelial activation and an inflammatory response. The rise in ET-1 and IL-6 is heavily influenced by the degree of exercise and hypoxia. ET-1 is an independent predictor of both AMS and its severity.
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Affiliation(s)
- Christopher John Boos
- 1 Department of Cardiology, Poole Hospital NHS Foundation Trust , Poole, Dorset, United Kingdom .,2 Department of Postgraduate Medical Education, Bournemouth University , Bournemouth, United Kingdom
| | - David R Woods
- 3 Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary , Newcastle, United Kingdom .,4 Defence Medical Services , Lichfield, United Kingdom .,5 University of Newcastle , Newcastle upon Tyne, United Kingdom .,6 Leeds Beckett University , Leeds, United Kingdom
| | | | | | | | - Adrian J Mellor
- 4 Defence Medical Services , Lichfield, United Kingdom .,7 Singulex, Inc. , Alameda, California.,8 James Cook University Hospital , Middlesbrough, United Kingdom
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