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Zila-Velasque JP, Grados-Espinoza P, Morán-Mariños C, Morales Pocco KO, Capcha-Jimenez US, Ortiz-Benique ZN. Adaptation and altitude sickness: A 40-year bibliometric analysis and collaborative networks. Front Public Health 2023; 11:1069212. [PMID: 36935697 PMCID: PMC10018125 DOI: 10.3389/fpubh.2023.1069212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
Introduction We analyze the scientific production and collaboration networks of studies based on adaptation and altitude diseases in the period 1980-2020. Methods The publications were extracted from journals indexed in Scopus. The bibliometric analysis was used to analyze the scientific production, including the number of annual publications, the documents, and the characteristics of the publications. With the VOSviewer software, the analysis of collaborative networks, productivity of the countries, as well as the analysis of the co-occurrence of keywords were visualized. Results 15,240 documents were registered, of which 3,985 documents were analyzed. A significant trend was observed in the number of publications (R 2: 0.9847; P: < 0.001), with annual growth of 4.6%. The largest number of publications were original articles (77.8%), these published more frequently in the journal "Altitude Medicine and Biology". The largest number of countries were from Europe and Asia; however, the largest collaboration network was with the United States. Of the countries with high altitudes, China and Peru ranked first in scientific productivity. The research priorities were on the adaptation mechanism (37.1%), mainly anoxia and respiratory function. Acute mountain sickness (18.4%) and pulmonary edema (14.7%) were the most reported diseases. Of the top 10 institutions, "University of Colorado" and "Universidad Peruana Cayetano Heredia" contributed more than 100 publications. Conclusions Scientific production on adaptation and altitude illnesses continues to grow. The United States and United Kingdom present collaborative networks with high-altitude countries. The research is aimed at studying the mechanisms of adaptation to altitude and acute mountain sickness.
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Affiliation(s)
- J. Pierre Zila-Velasque
- Red Latinoamericana de Medicina en la Altitud e Investigación, Pasco, Peru
- Facultad de Medicina Humana, Universidad Nacional Daniel Alcides Carrión, Pasco, Peru
- Unidad de Investigación en Bibliometría, Vicerrectorado de Investigación, Universidad San Ignacio de Loyola, Lima, Peru
| | - Pamela Grados-Espinoza
- Red Latinoamericana de Medicina en la Altitud e Investigación, Pasco, Peru
- Facultad de Medicina Humana, Universidad Nacional Daniel Alcides Carrión, Pasco, Peru
| | - Cristian Morán-Mariños
- Unidad de Investigación en Bibliometría, Vicerrectorado de Investigación, Universidad San Ignacio de Loyola, Lima, Peru
- Servicio de Neumología, Hospital Nacional Dos de Mayo, Lima, Peru
- Red de Eficacia Clinica y Sanitaria (REDECS), Lima, Peru
- *Correspondence: Cristian Morán-Mariños
| | - Kevin O. Morales Pocco
- Red Latinoamericana de Medicina en la Altitud e Investigación, Pasco, Peru
- Universidad Nacional del Altiplano Puno, Puno, Peru
- Asociación Científica de Estudiantes de Medicina – UNAP, Puno, Peru
| | - Uriel S. Capcha-Jimenez
- Red Latinoamericana de Medicina en la Altitud e Investigación, Pasco, Peru
- Facultad de Medicina, Universidad Nacional Mayor de San Marcos, Lima, Peru
- Sociedad Científica de San Fernando, Lima, Peru
| | - Zhamanda N. Ortiz-Benique
- Red Latinoamericana de Medicina en la Altitud e Investigación, Pasco, Peru
- Facultad de Medicina, Universidad Nacional de San Agustín, Arequipa, Peru
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Boos CJ, Mellor A, Woods DR, O’Hara JP. The Effect of High-Altitude Acclimatisation on Ultra-Short Heart Rate Variability. Front Cardiovasc Med 2022; 9:787147. [PMID: 35419439 PMCID: PMC8995742 DOI: 10.3389/fcvm.2022.787147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/28/2022] [Indexed: 11/21/2022] Open
Abstract
Introduction High-altitude (HA) exposure affects heart rate variability (HRV) and has been inconsistently linked to acute mountain sickness (AMS). The influence of increasing HA exposure on ultra-short HRV and its relationship to gold standard HRV measures at HA has not been examined. Methods This was a prospective observational study of adults aged ≥ 18 years undertaking a HA trek in the Dhaulagiri region of the Himalayas. Cardiac inter-beat-intervals were obtained from a 10-s recording of supra-systolic blood pressure (Uscom BP+ device) immediately followed by 300 s single lead ECG recording (CheckMyHeart device). HRV was measured using the RMSSD (root mean square of successive differences of NN intervals) at sea level (SL) in the United Kingdom and at 3,619, 4,600, and 5,140 m at HA. Oxygen saturations (SpO2) were measured using finger-based pulse oximetry. The level of agreement between the 10 and 300 s RMSSD values were examined using a modified Bland–Altman relative-difference analysis. Results Overall, 89 participants aged 32.2 ± 8.8 years (range 18–56) were included of which 70.8% were men. HA exposure (SL vs. 3,619 m) was associated with an initial increase in both 10 s (45.0 [31.0–82.0]) vs. 58.0 [33.0–119.0] ms) and 300 s (45.67 [33.24–70.32] vs. 56.48 [36.98–102.0] ms) in RMSSD. Thereafter at 4,600 and 5,140 m both 10 and 300 s RMSSD values were significantly lower than SL. From a total of 317 paired HRV measures the 10 and 300 s RMSSD measures were moderately correlated (Spearman r = 0.66; 95% CI: 0.59–0.72; p < 0.0001). The median difference (bias) in RMSSD values (300 s − 10 s) was −2.3 ms with a lower and upper limit of agreement of −107.5 and 88.61 ms, respectively with no differences with altitude. Overall, 293/317 (92.4%) of all paired HRV values fell within the 95% CI limits of agreement. Neither HRV method was predictive of AMS. Conclusion Increasing HA affects ultra-short HRV in a similar manner to gold-standard 300 s. Ultra-short HRV has a moderate agreement with 300 s measurements. HRV did not predict AMS.
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Affiliation(s)
- Christopher John Boos
- Department of Cardiology, Poole Hospital, University Hospitals Dorset, Poole, United Kingdom
- Department of Postgraduate Medical Education, Bournemouth University, Bournemouth, United Kingdom
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
- *Correspondence: Christopher John Boos,
| | - Adrian Mellor
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
- Defence Medical Services, Lichfield, United Kingdom
- James Cook University Hospital, Middlesbrough, United Kingdom
| | - David Richard Woods
- Defence Medical Services, Lichfield, United Kingdom
- Northumbria NHS Foundation Trust, North Shields, United Kingdom
- Academic Department of Medicine, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - John Paul O’Hara
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
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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] [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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Griffiths A, Deighton K, Shannon OM, Boos C, Rowe J, Matu J, King R, O'Hara JP. Appetite and energy intake responses to breakfast consumption and carbohydrate supplementation in hypoxia. Appetite 2020; 147:104564. [PMID: 31870935 DOI: 10.1016/j.appet.2019.104564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/29/2019] [Accepted: 12/17/2019] [Indexed: 02/08/2023]
Abstract
PURPOSE The purpose of experiment one was to determine the appetite, acylated ghrelin and energy intake response to breakfast consumption and omission in hypoxia and normoxia. Experiment two aimed to determine the appetite, acylated ghrelin and energy intake response to carbohydrate supplementation after both breakfast consumption and omission in hypoxia. METHODS In experiment one, twelve participants rested and exercised once after breakfast consumption and once after omission in normobaric hypoxia (4300 m: FiO2 ~11.7%) and normoxia. In experiment two, eleven participants rested and exercised in normobaric hypoxia (4300 m: FiO2 ~11.7%), twice after consuming a high carbohydrate breakfast and twice after breakfast omission. Participants consumed both a carbohydrate (1.2g·min-1 glucose) and a placebo beverage after breakfast consumption and omission. Measures of appetite perceptions and acylated ghrelin were taken at regular intervals throughout both experiments and an ad-libitum meal was provided post-exercise to quantify energy intake. RESULTS Breakfast consumption had no significant effect on post exercise energy intake or acylated ghrelin concentrations, despite reductions in appetite perceptions. As such, breakfast consumption increased total trial energy intake compared with breakfast omission in hypoxia (7136 ± 2047 kJ vs. 5412 ± 1652 kJ; p = 0.02) and normoxia (9276 ± 3058 vs. 6654 ± 2091 kJ; p < 0.01). Carbohydrate supplementation had no effect on appetite perceptions or acylated ghrelin concentrations after breakfast consumption or omission. As such, carbohydrate supplementation increased total energy intake after breakfast consumption (10222 ± 2831 kJ vs. 7695 ± 1970 kJ p < 0.01) and omission (8058 ± 2574 kJ vs. 6174 ± 2222 kJ p = 0.02). CONCLUSION Both breakfast consumption and carbohydrate supplementation provide beneficial dietary interventions for increasing energy intake in hypoxic conditions.
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Affiliation(s)
- Alex Griffiths
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - Kevin Deighton
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - Oliver M Shannon
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK; Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Leech Building, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK.
| | - Chris Boos
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK; Department of Cardiology, Poole Hospital NHS Trust, Poole, BH15 2JB, UK.
| | - Joshua Rowe
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - Jamie Matu
- School of Clinical and Applied Science, Leeds Beckett University, Leeds, LS1 3HE, UK.
| | - Roderick King
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - John P O'Hara
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
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Griffiths A, Deighton K, Shannon OM, Matu J, King R, O'Hara JP. Substrate oxidation and the influence of breakfast in normobaric hypoxia and normoxia. Eur J Appl Physiol 2019; 119:1909-1920. [PMID: 31270614 PMCID: PMC6694084 DOI: 10.1007/s00421-019-04179-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/17/2019] [Indexed: 11/02/2022]
Abstract
PURPOSE Previous research has reported inconsistent effects of hypoxia on substrate oxidation, which may be due to differences in methodological design, such as pre-exercise nutritional status and exercise intensity. This study investigated the effect of breakfast consumption on substrate oxidation at varying exercise intensities in normobaric hypoxia compared with normoxia. METHODS Twelve participants rested and exercised once after breakfast consumption and once after omission in normobaric hypoxia (4300 m: FiO2 ~ 11.7%) and normoxia. Exercise consisted of walking for 20 min at 40%, 50% and 60% of altitude-specific [Formula: see text]O2max at 10-15% gradient with a 10 kg backpack. Indirect calorimetry was used to calculate carbohydrate and fat oxidation. RESULTS The relative contribution of carbohydrate oxidation to energy expenditure was significantly reduced in hypoxia compared with normoxia during exercise after breakfast omission at 40% (22.4 ± 17.5% vs. 38.5 ± 15.5%, p = 0.03) and 60% [Formula: see text]O2max (35.4 ± 12.4 vs. 50.1 ± 17.6%, p = 0.03), with a trend observed at 50% [Formula: see text]O2max (23.6 ± 17.9% vs. 38.1 ± 17.0%, p = 0.07). The relative contribution of carbohydrate oxidation to energy expenditure was not significantly different in hypoxia compared with normoxia during exercise after breakfast consumption at 40% (42.4 ± 15.7% vs. 48.5 ± 13.3%, p = 0.99), 50% (43.1 ± 11.7% vs. 47.1 ± 14.0%, p = 0.99) and 60% [Formula: see text]O2max (54.6 ± 17.8% vs. 55.1 ± 15.0%, p = 0.99). CONCLUSIONS Relative carbohydrate oxidation was significantly reduced in hypoxia compared with normoxia during exercise after breakfast omission but not during exercise after breakfast consumption. This response remained consistent with increasing exercise intensities. These findings may explain some of the disparity in the literature.
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Affiliation(s)
- Alex Griffiths
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
| | - Kevin Deighton
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Oliver M Shannon
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Leech Building, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Jamie Matu
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Roderick King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
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HILL NEILE, DEIGHTON KEVIN, MATU JAMIE, MISRA SHIVANI, OLIVER NICKS, NEWMAN CARRIE, MELLOR ADRIAN, O’HARA JOHN, WOODS DAVID. Continuous Glucose Monitoring at High Altitude—Effects on Glucose Homeostasis. Med Sci Sports Exerc 2018; 50:1679-1686. [DOI: 10.1249/mss.0000000000001624] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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7
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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] [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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Smyth MJ, Round JA, Mellor AJ. Remote physiological monitoring in an austere environment: a future for battlefield care provision? J ROY ARMY MED CORPS 2018; 164:410-413. [DOI: 10.1136/jramc-2017-000905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/17/2018] [Accepted: 04/18/2018] [Indexed: 11/03/2022]
Abstract
Wearable technologies are making considerable advances into the mainstream as they become smaller and more user friendly. The global market for such devices is forecasted to be worth over US$5 billion in 2018, with one in six people owning a device. Many professional sporting teams use self-monitoring to assess physiological parameters and work rate on the pitch, highlighting the potential utility for military command chains. As size of device reduces and sensitivity improves, coupled with remote connectivity technology, integration into the military environment could be relatively seamless. Remote monitoring of personnel on the ground, giving live updates on their physiological status, would allow commanders or medical officers the ability to manage their soldiers appropriately and improve combat effectiveness. This paper explores a proof of concept for the use of a self-monitoring system in the austere high altitude environment of the Nepalese Himalayas, akin to those experienced by modern militaries fighting in remote locations. It also reviews, in part, the historical development of remote monitoring technologies. The system allowed for physiological recordings, plotted against GPS position, to be remotely monitored in Italy. Examples of the data recorded are given and the performance of the system is discussed, including limitations, potential areas of development and how systems like this one could be integrated into the military environment.
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Changes in balance and joint position sense during a 12-day high altitude trek: The British Services Dhaulagiri medical research expedition. PLoS One 2018; 13:e0190919. [PMID: 29342191 PMCID: PMC5771604 DOI: 10.1371/journal.pone.0190919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 12/23/2017] [Indexed: 11/19/2022] Open
Abstract
Postural control and joint position sense are essential for safely undertaking leisure and professional activities, particularly at high altitude. We tested whether exposure to a 12-day trek with a gradual ascent to high altitude impairs postural control and joint position sense. This was a repeated measures observational study of 12 military service personnel (28±4 years). Postural control (sway velocity measured by a portable force platform) during standing balance, a Sharpened Romberg Test and knee joint position sense were measured, in England (113m elevation) and at 3 research camps (3619m, 4600m and 5140m) on a 12-day high altitude trek in the Dhaulagiri region of Nepal. Pulse oximetry, and Lake Louise scores were also recorded on the morning and evening of each trek day. Data were compared between altitudes and relationships between pulse oximetry, Lake Louise score, and sway velocity were explored. Total sway velocity during standing balance with eyes open (p = 0.003, d = 1.9) and during Sharpened Romberg test with eyes open (p = 0.007, d = 1.6) was significantly greater at altitudes of 3619m and 5140m when compared with sea level. Anterior-posterior sway velocity during standing balance with eyes open was also significantly greater at altitudes of 3619m and 5140m when compared with sea level (p = 0.001, d = 1.9). Knee joint position sense was not altered at higher altitudes. There were no significant correlations between Lake Louise scores, pulse oximetry and postural sway. Despite a gradual ascent profile, exposure to 3619 m was associated with impairments in postural control without impairment in knee joint position sense. Importantly, these impairments did not worsen at higher altitudes of 4600 m or 5140 m. The present findings should be considered during future trekking expeditions when developing training strategies targeted to manage impairments in postural control that occur with increasing altitude.
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Matu J, Deighton K, Ispoglou T, Shannon OM, Duckworth L. A high fat breakfast attenuates the suppression of appetite and acylated ghrelin during exercise at simulated altitude. Physiol Behav 2017; 179:353-360. [DOI: 10.1016/j.physbeh.2017.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/28/2017] [Accepted: 07/04/2017] [Indexed: 12/28/2022]
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Matu J, O'Hara J, Hill N, Clarke S, Boos C, Newman C, Holdsworth D, Ispoglou T, Duckworth L, Woods D, Mellor A, Deighton K. Changes in appetite, energy intake, body composition, and circulating ghrelin constituents during an incremental trekking ascent to high altitude. Eur J Appl Physiol 2017; 117:1917-1928. [PMID: 28741038 PMCID: PMC5556141 DOI: 10.1007/s00421-017-3683-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/16/2017] [Indexed: 12/23/2022]
Abstract
Purpose Circulating acylated ghrelin concentrations are associated with altitude-induced anorexia in laboratory environments, but have never been measured at terrestrial altitude. This study examined time course changes in appetite, energy intake, body composition, and ghrelin constituents during a high-altitude trek. Methods Twelve participants [age: 28(4) years, BMI 23.0(2.1) kg m−2] completed a 14-day trek in the Himalayas. Energy intake, appetite perceptions, body composition, and circulating acylated, des-acylated, and total ghrelin concentrations were assessed at baseline (113 m, 12 days prior to departure) and at three fixed research camps during the trek (3619 m, day 7; 4600 m, day 10; 5140 m, day 12). Results Relative to baseline, energy intake was lower at 3619 m (P = 0.038) and 5140 m (P = 0.016) and tended to be lower at 4600 m (P = 0.056). Appetite perceptions were lower at 5140 m (P = 0.027) compared with baseline. Acylated ghrelin concentrations were lower at 3619 m (P = 0.046) and 4600 m (P = 0.038), and tended to be lower at 5140 m (P = 0.070), compared with baseline. Des-acylated ghrelin concentrations did not significantly change during the trek (P = 0.177). Total ghrelin concentrations decreased from baseline to 4600 m (P = 0.045). Skinfold thickness was lower at all points during the trek compared with baseline (P ≤ 0.001) and calf girth decreased incrementally during the trek (P = 0.010). Conclusions Changes in plasma acylated and total ghrelin concentrations may contribute to the suppression of appetite and energy intake at altitude, but differences in the time course of these responses suggest that additional factors are also involved. Interventions are required to maintain appetite and energy balance during trekking at terrestrial altitudes.
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Affiliation(s)
- Jamie Matu
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - John O'Hara
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Neil Hill
- Section of Investigative Medicine, Imperial College London, London, UK.,Royal Centre for Defence Medicine, ICT Building, Vincent Drive, Birmingham, UK
| | - Sarah Clarke
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Christopher Boos
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Poole Hospital NHS Trust, Longfleet Rd, Poole, UK
| | - Caroline Newman
- Royal Centre for Defence Medicine, ICT Building, Vincent Drive, Birmingham, UK
| | - David Holdsworth
- Royal Centre for Defence Medicine, ICT Building, Vincent Drive, Birmingham, UK
| | - Theocharis Ispoglou
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Lauren Duckworth
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - David Woods
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Royal Centre for Defence Medicine, ICT Building, Vincent Drive, Birmingham, UK
| | - Adrian Mellor
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.,Royal Centre for Defence Medicine, ICT Building, Vincent Drive, Birmingham, UK
| | - Kevin Deighton
- Institute for Sport Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QS, UK.
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Shannon OM, Duckworth L, Barlow MJ, Deighton K, Matu J, Williams EL, Woods D, Xie L, Stephan BCM, Siervo M, O'Hara JP. Effects of Dietary Nitrate Supplementation on Physiological Responses, Cognitive Function, and Exercise Performance at Moderate and Very-High Simulated Altitude. Front Physiol 2017. [PMID: 28649204 PMCID: PMC5465306 DOI: 10.3389/fphys.2017.00401] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose: Nitric oxide (NO) bioavailability is reduced during acute altitude exposure, contributing toward the decline in physiological and cognitive function in this environment. This study evaluated the effects of nitrate (NO3−) supplementation on NO bioavailability, physiological and cognitive function, and exercise performance at moderate and very-high simulated altitude. Methods:Ten males (mean (SD): V˙O2max: 60.9 (10.1) ml·kg−1·min−1) rested and performed exercise twice at moderate (~14.0% O2; ~3,000 m) and twice at very-high (~11.7% O2; ~4,300 m) simulated altitude. Participants ingested either 140 ml concentrated NO3−-rich (BRJ; ~12.5 mmol NO3−) or NO3−-deplete (PLA; 0.01 mmol NO3−) beetroot juice 2 h before each trial. Participants rested for 45 min in normobaric hypoxia prior to completing an exercise task. Exercise comprised a 45 min walk at 30% V˙O2max and a 3 km time-trial (TT), both conducted on a treadmill at a 10% gradient whilst carrying a 10 kg backpack to simulate altitude hiking. Plasma nitrite concentration ([NO2−]), peripheral oxygen saturation (SpO2), pulmonary oxygen uptake (V˙O2), muscle and cerebral oxygenation, and cognitive function were measured throughout. Results: Pre-exercise plasma [NO2−] was significantly elevated in BRJ compared with PLA (p = 0.001). Pulmonary V˙O2 was reduced (p = 0.020), and SpO2 was elevated (p = 0.005) during steady-state exercise in BRJ compared with PLA, with similar effects at both altitudes. BRJ supplementation enhanced 3 km TT performance relative to PLA by 3.8% [1,653.9 (261.3) vs. 1718.7 (213.0) s] and 4.2% [1,809.8 (262.0) vs. 1,889.1 (203.9) s] at 3,000 and 4,300 m, respectively (p = 0.019). Oxygenation of the gastrocnemius was elevated during the TT consequent to BRJ (p = 0.011). The number of false alarms during the Rapid Visual Information Processing Task tended to be lower with BRJ compared with PLA prior to altitude exposure (p = 0.056). Performance in all other cognitive tasks did not differ significantly between BRJ and PLA at any measurement point (p ≥ 0.141). Conclusion: This study suggests that BRJ improves physiological function and exercise performance, but not cognitive function, at simulated moderate and very-high altitude.
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Affiliation(s)
- Oliver M Shannon
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
| | - Lauren Duckworth
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
| | - Matthew J Barlow
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
| | - Kevin Deighton
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
| | - Jamie Matu
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
| | - Emily L Williams
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
| | - David Woods
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom.,Defence Medical Services, Royal Centre for Defence MedicineBirmingham, United Kingdom
| | - Long Xie
- Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Blossom C M Stephan
- Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Mario Siervo
- Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - John P O'Hara
- Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett UniversityLeeds, United Kingdom
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