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Kunutsor SK, Lehoczki A, Laukkanen JA. The untapped potential of cold water therapy as part of a lifestyle intervention for promoting healthy aging. GeroScience 2024:10.1007/s11357-024-01295-w. [PMID: 39078461 DOI: 10.1007/s11357-024-01295-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/19/2024] [Indexed: 07/31/2024] Open
Abstract
Healthy aging is a crucial goal in aging societies of the western world, with various lifestyle strategies being employed to achieve it. Among these strategies, hydrotherapy stands out for its potential to promote cardiovascular and mental health. Cold water therapy, a hydrotherapy technique, has emerged as a lifestyle strategy with the potential capacity to evoke a wide array of health benefits. This review aims to synthesize the extensive body of research surrounding cold water therapy and its beneficial effects on various health systems as well as the underlying biological mechanisms driving these benefits. We conducted a search for interventional and observational cohort studies from MEDLINE and EMBASE up to July 2024. Deliberate exposure of the body to cold water results in distinct physiological responses that may be linked to several health benefits. Evidence, primarily from small interventional studies, suggests that cold water therapy positively impacts cardiometabolic risk factors, stimulates brown adipose tissue and promotes energy expenditure-potentially reducing the risk of cardiometabolic diseases. It also triggers the release of stress hormones, catecholamines and endorphins, enhancing alertness and elevating mood, which may alleviate mental health conditions. Cold water therapy also reduces inflammation, boosts the immune system, promotes sleep and enhances recovery following exercise. The optimal duration and temperature needed to derive maximal benefits is uncertain but current evidence suggests that short-term exposure and lower temperatures may be more beneficial. Overall, cold water therapy presents a potential lifestyle strategy to enhancing physical and mental well-being, promoting healthy aging and extending the healthspan, but definitive interventional evidence is warranted.
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Affiliation(s)
- Setor K Kunutsor
- Section of Cardiology, Department of Internal Medicine, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R2H 2A6, Canada.
- Leicester Real World Evidence Unit, Diabetes Research Centre, University of Leicester, Leicester General Hospital, Gwendolen Road, Leicester, LE5 4WP, UK.
| | - Andrea Lehoczki
- Department of Preventive Medicine and Public Health, Semmelweis University, Budapest, Hungary
| | - Jari A Laukkanen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
- Institute of Clinical Medicine, Department of Medicine, University of Eastern Finland, Kuopio, Finland
- Wellbeing Services County of Central Finland, Department of Medicine, Finland District, Jyväskylä, Finland
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Liedl HJ, Lazenby KA, Arimoto RS, Singh A, Strelzow JA. Normothermia to Decrease Surgical Site Infection Risk: Silver Bullet or Fool's Gold? A Retrospective Cohort Study. J Am Acad Orthop Surg Glob Res Rev 2024; 8:01979360-202406000-00008. [PMID: 38875451 PMCID: PMC11191004 DOI: 10.5435/jaaosglobal-d-23-00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/08/2024] [Accepted: 04/02/2024] [Indexed: 06/16/2024]
Abstract
PURPOSE Surgical site infection (SSI) is the leading cause of nosocomial infections among surgical patients in the United States. Currently, there is compelling evidence suggesting that temperature dysregulation in surgical patients may be a risk factor for the development of SSI. We examined the relationship between perioperative hypothermia (PH) and SSI in a population of surgical patients with diabetes mellitus (DM). METHODS This retrospective cohort review was conducted on patients with a history of DM undergoing orthopaedic surgery at our institution between May 1, 2018, and April 1, 2022. Inclusion criteria were age older than 15 years, a history of DM or recent hemoglobin A1c concentration of ≥6.5%, and operation of at least 60 minutes under general anesthesia. Perioperative hypothermia was defined as an intraoperative temperature ≤ 35.5°C. Continuous variables were compared using the t-test and Wilcoxon rank-sum test. Categorical variables were compared using the chi-squared test. We constructed a multivariable logistic regression model to estimate SSI risk while controlling for demographic variables. RESULTS A total of 236 patients were included in the final analysis. The overall incidence of SSI was 5.93%. 99 patients (42%) experienced PH. No difference was observed in the risk of SSI between the normothermic and hypothermic cohorts. Among the 99 patients who experienced PH, increasing HbA1c was associated with increasing risk of SSI (OR = 2.39, 95% CI = 1.12 to 5.32, P-value = 0.0222). The multivariable logistic regression model had good discriminatory ability (c-statistic 0.74, 95% CI: 0.61 to 0.89) and good predictive accuracy (sensitivity 64%, specificity 73%). DISCUSSION PH is not an independent risk factor of SSI. However, in the presence of elevated HbA1c, PH may more than double the risk of SSI. Perioperative hypothermia may be an additive risk factor in the setting of poor glycemic control and potentially in the setting of other known risk factors.
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Affiliation(s)
- Henry J.C. Liedl
- From the Department of Orthopaedic Surgery, University of Chicago Medicine, Chicago, IL (Dr. Liedl and Dr. Strelzow), and the Pritzker School of Medicine, University of Chicago, Chicago, IL (Dr. Liedl, Dr. Lazenby, Dr. Arimoto, and Mr. Singh)
| | - Kevin A. Lazenby
- From the Department of Orthopaedic Surgery, University of Chicago Medicine, Chicago, IL (Dr. Liedl and Dr. Strelzow), and the Pritzker School of Medicine, University of Chicago, Chicago, IL (Dr. Liedl, Dr. Lazenby, Dr. Arimoto, and Mr. Singh)
| | - Ryuji S. Arimoto
- From the Department of Orthopaedic Surgery, University of Chicago Medicine, Chicago, IL (Dr. Liedl and Dr. Strelzow), and the Pritzker School of Medicine, University of Chicago, Chicago, IL (Dr. Liedl, Dr. Lazenby, Dr. Arimoto, and Mr. Singh)
| | - Armaan Singh
- From the Department of Orthopaedic Surgery, University of Chicago Medicine, Chicago, IL (Dr. Liedl and Dr. Strelzow), and the Pritzker School of Medicine, University of Chicago, Chicago, IL (Dr. Liedl, Dr. Lazenby, Dr. Arimoto, and Mr. Singh)
| | - Jason A. Strelzow
- From the Department of Orthopaedic Surgery, University of Chicago Medicine, Chicago, IL (Dr. Liedl and Dr. Strelzow), and the Pritzker School of Medicine, University of Chicago, Chicago, IL (Dr. Liedl, Dr. Lazenby, Dr. Arimoto, and Mr. Singh)
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King KE, McCormick JJ, McManus MK, Janetos KMT, Goulet N, Kenny GP. Impaired autophagy following ex vivo cooling of simulated hypothermic temperatures in peripheral blood mononuclear cells from young and older adults. J Therm Biol 2024; 121:103831. [PMID: 38565070 DOI: 10.1016/j.jtherbio.2024.103831] [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: 09/29/2023] [Revised: 12/20/2023] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
Hypothermia is a critical consequence of extreme cold exposure that increases the risk of cold-related injury and death in humans. While the initiation of cytoprotective mechanisms including the process of autophagy and the heat shock response (HSR) is crucial to cellular survival during periods of stress, age-related decrements in these systems may underlie cold-induced cellular vulnerability in older adults. Moreover, whether potential sex-related differences in autophagic regulation influence the human cold stress response remain unknown. We evaluated the effect of age and sex on mechanisms of cytoprotection (autophagy and the HSR) and cellular stress (apoptotic signaling and the acute inflammatory response) during ex vivo hypothermic cooling. Venous blood samples from 20 healthy young (10 females; mean [SD]: 22 [2] years) and 20 healthy older (10 females; 66 [5] years) adults were either isolated immediately (baseline) for peripheral blood mononuclear cells (PBMCs) or exposed to water bath temperatures maintained at 37, 35, 33, 31, or 4 °C for 90 min before PBMC isolation. Proteins associated with autophagy, apoptosis, the HSR, and inflammation were analyzed via Western blotting. Indicators of autophagic initiation and signaling (LC3, ULK1, and beclin-2) and the HSR (HSP90 and HSP70) increased when exposed to hypothermic temperatures in young and older adults (all p ≤ 0.007). Sex-related differences were only observed with autophagic initiation (ULK1; p = 0.015). However, despite increases in autophagic initiators ULK1 and beclin-2 (all p < 0.001), this was paralleled by autophagic dysfunction (increased p62) in all groups (all p < 0.001). Further, apoptotic (cleaved-caspase-3) and inflammatory (IL-6 and TNF-α) signaling increased in all groups (all p < 0.001). We demonstrated that exposure to hypothermic conditions is associated with autophagic dysfunction, irrespective of age or sex, although there may exist innate sex-related differences in cytoprotection in response to cold exposure as evidenced through altered autophagic initiation.
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Affiliation(s)
- Kelli E King
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - James J McCormick
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Morgan K McManus
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Kristina-Marie T Janetos
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Nicholas Goulet
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada; Behavioural and Metabolic Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada; Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
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Błażejczyk K, Havenith G, Szymczak RK. Simulations of the human heat balance during Mount Everest summit attempts in spring and winter. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2024; 68:351-366. [PMID: 38114844 PMCID: PMC10794380 DOI: 10.1007/s00484-023-02594-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 09/15/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
The majority of research dealing with the impacts of the Himalayan climate on human physiology focuses on low air temperature, high wind speed, and low air pressure and oxygen content, potentially leading to hypothermia and hypoxia. Only a few studies describe the influence of the weather conditions in the Himalayas on the body's ability to maintain thermal balance. The aim of the present research is to trace the heat exchange between humans and their surroundings during a typical, 6-day summit attempt of Mount Everest in the spring and winter seasons. Additionally, an emergency night outdoors without tent protection is considered. Daily variation of the heat balance components were calculated by the MENEX_HA model using meteorological data collected at automatic weather stations installed during a National Geographic expedition in 2019-2020. The data represent the hourly values of the measured meteorological parameters. The research shows that in spite of extreme environmental conditions in the sub-summit zone of Mount Everest during the spring weather window, it is possible to keep heat equilibrium of the climbers' body. This can be achieved by the use of appropriate clothing and by regulating activity level. In winter, extreme environmental conditions in the sub-summit zone make it impossible to maintain heat equilibrium and lead to hypothermia. The emergency night in the sub-peak zone leads to gradual cooling of the body which in winter can cause severe hypothermia of the climber's body. At altitudes < 7000 m, climbers should consider using clothing that allows variation of insulation and active regulation of their fit around the body.
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Affiliation(s)
- Krzysztof Błażejczyk
- Institute of Geography and Spatial Organization, Polish Academy of Sciences, Twarda 51/55, 02-818, Warszawa, Poland.
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough School of Design & Creative Arts, Loughborough University, Loughborough, UK
| | - Robert K Szymczak
- Department of Emergency Medicine, Faculty of Health Sciences, Medical University of Gdańsk, Gdańsk, Poland
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Giraud D, Pomportes L, Nicol C, Bertin D, Gardarein JL, Hays A. Mechanism involved of post-exercise cold water immersion: Blood redistribution and increase in energy expenditure during rewarming. Temperature (Austin) 2024; 11:137-156. [PMID: 38846524 PMCID: PMC11152100 DOI: 10.1080/23328940.2024.2303332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/03/2024] [Indexed: 06/09/2024] Open
Abstract
Thermogenesis is well understood, but the relationships between cold water immersion (CWI), the post-CWI rewarming and the associated physiological changes are not. This study investigated muscle and systemic oxygenation, cardiorespiratory and hemodynamic responses, and gastrointestinal temperature during and after CWI. 21 healthy men completed randomly 2 protocols. Both protocols consisted of a 48 minutes heating cycling exercise followed by 3 recovery periods (R1-R3), but they differed in R2. R1 lasted 20 minutes in a passive semi-seated position on a physiotherapy table at ambient room temperature. Depending on the protocol, R2 lasted 15 minutes at either ambient condition (R2_AMB) or in a CWI condition at 10°C up to the iliac crest (R2_CWI). R3 lasted 40 minutes at AMB while favoring rewarming after R2_CWI. This was followed by 10 minutes of cycling. Compared to R2_AMB, R2_CWI ended at higherV ˙ O2 in the non-immersed body part due to thermogenesis (7.16(2.15) vs. 4.83(1.62) ml.min-1.kg-1) and lower femoral artery blood flow (475(165) vs. 704(257) ml.min-1) (p < 0.001). Only after CWI, R3 showed a progressive decrease in vastus and gastrocnemius medialis O2 saturation, significant after 34 minutes (p < 0.001). As blood flow did not differ from the AMB protocol, this indicated local thermogenesis in the immersed part of the body. After CWI, a lower gastrointestinal temperature on resumption of cycling compared to AMB (36.31(0.45) vs. 37.30(0.49) °C, p < 0.001) indicated incomplete muscle thermogenesis. In conclusion, the rewarming period after CWI was non-linear and metabolically costly. Immersion and rewarming should be considered as a continuum rather than separate events.
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Affiliation(s)
- Dorian Giraud
- Faculty of Medical and Paramedical Sciences, Aix-Marseille University, HIPE Human Lab, Marseille, France
- Polytech Marseille, Aix-Marseille University, CNRS, IUSTI, Marseille, France
| | - Laura Pomportes
- Faculty of Sport Science, Aix-Marseille University, CNRS, ISM, Marseille, France
| | - Caroline Nicol
- Faculty of Sport Science, Aix-Marseille University, CNRS, ISM, Marseille, France
| | - Denis Bertin
- Faculty of Medical and Paramedical Sciences, Aix-Marseille University, HIPE Human Lab, Marseille, France
- Faculty of Sport Science, Aix-Marseille University, CNRS, ISM, Marseille, France
| | | | - Arnaud Hays
- Faculty of Medical and Paramedical Sciences, Aix-Marseille University, HIPE Human Lab, Marseille, France
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Wallace PJ, Hartley GL, Nowlan JG, Ljubanovich J, Sieh N, Taber MJ, Gagnon DD, Cheung SS. Endurance capacity impairment in cold air ranging from skin cooling to mild hypothermia. J Appl Physiol (1985) 2024; 136:58-69. [PMID: 37942528 DOI: 10.1152/japplphysiol.00663.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/20/2023] [Accepted: 11/06/2023] [Indexed: 11/10/2023] Open
Abstract
We tested the effects of cold air (0°C) exposure on endurance capacity to different levels of cold strain ranging from skin cooling to core cooling of Δ-1.0°C. Ten males completed a randomized, crossover, control study consisting of a cycling time to exhaustion (TTE) at 70% of their peak power output following: 1) 30-min of exposure to 22°C thermoneutral air (TN), 2) 30-min exposure to 0°C air leading to a cold shell (CS), 3) 0°C air exposure causing mild hypothermia of -0.5°C from baseline rectal temperature (HYPO-0.5°C), and 4) 0°C air exposure causing mild hypothermia of -1.0°C from baseline rectal temperature (HYPO-1.0°C). The latter three conditions tested TTE in 0°C air. Core temperature and seven-site mean skin temperature at the start of the TTE were: TN (37.0 ± 0.2°C, 31.2 ± 0.8°C), CS (37.1 ± 0.3°C, 25.5 ± 1.4°C), HYPO-0.5°C (36.6 ± 0.4°C, 22.3 ± 2.2°C), HYPO-1.0°C (36.4 ± 0.5°C, 21.4 ± 2.7°C). There was a significant condition effect (P ≤ 0.001) for TTE, which from TN (23.75 ± 13.75 min) to CS (16.22 ± 10.30 min, Δ-30.9 ± 21.5%, P = 0.055), HYPO-0.5°C (8.50 ± 5.23 min, Δ-61.4 ± 19.7%, P ≤ 0.001), and HYPO-1.0°C (6.50 ± 5.60 min, Δ-71.6 ± 16.4%, P ≤ 0.001). Furthermore, participants had a greater endurance capacity in CS compared with HYPO-0.5°C (P = 0.046), and HYPO-1.0°C (P = 0.007), with no differences between HYPO-0.5°C and HYPO-1.0°C (P = 1.00). Endurance capacity impairment at 70% peak power output occurs early in cold exposure with skin cooling, with significantly larger impairments with mild hypothermia up to Δ-1.0°C.NEW & NOTEWORTHY We developed a novel protocol that cooled skin temperature, or skin plus core temperature (Δ-0.5°C or Δ-1.0 °C), to determine a dose-response of cold exposure on endurance capacity at 70% peak power output. Skin cooling significantly impaired exercise tolerance time by ∼31%, whereas core cooling led to a further reduction of 30%-40% with no difference between Δ-0.5°C and Δ-1.0°C. Overall, simply cooling the skin impaired endurance capacity, but this impairment is further magnified by core cooling.
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Affiliation(s)
- Phillip J Wallace
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Geoffrey L Hartley
- Department of Physical and Health Education, Nipissing University, North Bay, Ontario, Canada
| | - Josh G Nowlan
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Johnathan Ljubanovich
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Nina Sieh
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Michael J Taber
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
- N2M Consulting Inc., St. Catharines, Ontario, Canada
| | - Dominique D Gagnon
- School of Kinesiology and Health Sciences, Laurentian University, Sudbury, Ontario, Canada
- Faculty of Sports and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Clinic for Sports and Exercise Medicine, Department of Sports and Exercise Medicine, Faculty of Medicine, University of Helsinki Mäkelänkatu, Helsinki, Finland
| | - Stephen S Cheung
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise. Eur J Appl Physiol 2024; 124:1-145. [PMID: 37796292 DOI: 10.1007/s00421-023-05276-3] [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: 01/26/2023] [Accepted: 07/04/2023] [Indexed: 10/06/2023]
Abstract
In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Abramoff KJ, De Souza LL, Maloney SK, Davis EA, Jones TW, Fournier PA. Effect of Neck-Deep Immersion in Cool or Thermoneutral Water on Blood Glucose Levels in Individuals With Type 1 Diabetes. J Endocr Soc 2023; 7:bvad128. [PMID: 37942293 PMCID: PMC10628817 DOI: 10.1210/jendso/bvad128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Indexed: 11/10/2023] Open
Abstract
Context It is unclear whether immersion in cool water, typical of many beaches, increases the concentration of blood glucose in individuals with type 1 diabetes mellitus (T1DM). Objective To test the hypothesis in individuals with T1DM that immersion neck-deep in cool water (COOL) causes an increase in blood glucose concentration, but not exposure to thermoneutral water (THERMO) or thermoneutral air. Methods Eight overnight-fasted participants with T1DM were exposed for 60 minutes on separate days to 3 experimental conditions: cool water (COOL, 23 °C); thermoneutral water (THERMO, 33.5 °C); or thermoneutral air (24 °C). They then recovered for 60 minutes on land at 24 °C. At time intervals, we measured: blood glucose and plasma insulin concentration, rate of carbohydrate and fat oxidation, skin and core temperature, subcutaneous blood flow, and shivering via electromyography. Results There was no change in blood glucose concentration during the 3 experimental conditions (P > .05). During recovery after COOL, blood glucose increased (P < .05) but did not change in the other 2 conditions. The rate of carbohydrate oxidation during and early after COOL was higher than in the other 2 conditions (P < .05), and COOL led to a decrease in subcutaneous blood flow and the concentration of plasma insulin (P < .05). Conclusion Cool or thermoneutral neck-deep immersion in water does not cause a change in the concentration of blood glucose in people with T1DM, but on-land recovery from COOL causes an increase in blood glucose that may be due, at least in part, to the accompanying decrease in plasma insulin.
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Affiliation(s)
- Kristina J Abramoff
- Department of Sport Science, Exercise and Health, School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Department of Anatomy Physiology and Human Biology, School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Children's Diabetes Centre, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Lauren L De Souza
- Department of Sport Science, Exercise and Health, School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Shane K Maloney
- Department of Anatomy Physiology and Human Biology, School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Elizabeth A Davis
- Children's Diabetes Centre, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Timothy W Jones
- Children's Diabetes Centre, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Paul A Fournier
- Department of Sport Science, Exercise and Health, School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Children's Diabetes Centre, Telethon Kids Institute, Nedlands, WA 6009, Australia
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Niclou A, Sarma M, Levy S, Ocobock C. To the extreme! How biological anthropology can inform exercise physiology in extreme environments. Comp Biochem Physiol A Mol Integr Physiol 2023; 284:111476. [PMID: 37423419 DOI: 10.1016/j.cbpa.2023.111476] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/11/2023]
Abstract
The fields of biological anthropology and exercise physiology are closely related and can provide mutually beneficial insights into human performance. These fields often use similar methods and are both interested in how humans function, perform, and respond in extreme environments. However, these two fields have different perspectives, ask different questions, and work within different theoretical frameworks and timescales. Biological anthropologists and exercise physiologists can greatly benefit from working together when examining human adaptation, acclimatization, and athletic performance in the extremes of heat, cold, and high-altitude. Here we review the adaptations and acclimatizations in these three different extreme environments. We then examine how this work has informed and built upon exercise physiology research on human performance. Finally, we present an agenda for moving forward, hopefully, with these two fields working more closely together to produce innovative research that improves our holistic understanding of human performance capacities informed by evolutionary theory, modern human acclimatization, and the desire to produce immediate and direct benefits.
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Affiliation(s)
- Alexandra Niclou
- Pennington Biomedical Research Center, Baton Rouge, LA, United States of America. https://twitter.com/fiat_luxandra
| | - Mallika Sarma
- Human Space Flight Lab, Johns Hopkins School of Medicine, Baltimore, MD, United States of America. https://twitter.com/skyy_mal
| | - Stephanie Levy
- Department of Anthropology, CUNY Hunter College, New York, NY, United States of America; New York Consortium in Evolutionary Primatology, New York, NY, United States of America. https://twitter.com/slevyscience
| | - Cara Ocobock
- University of Notre Dame Department of Anthropology, Notre Dame, IN, United States of America; Eck Institute for Global Health, Institute for Educational Initiatives, University of Notre Dame, United States of America.
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Elmer J, Callaway CW. Temperature control after cardiac arrest. Resuscitation 2023; 189:109882. [PMID: 37355091 PMCID: PMC10530429 DOI: 10.1016/j.resuscitation.2023.109882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/26/2023]
Abstract
Managing temperature is an important part of post-cardiac arrest care. Fever or hyperthermia during the first few days after cardiac arrest is associated with worse outcomes in many studies. Clinical data have not determined any target temperature or duration of temperature management that clearly improves patient outcomes. Current guidelines and recent reviews recommend controlling temperature to prevent hyperthermia. Higher temperatures can lead to secondary brain injury by increasing seizures, brain edema and metabolic demand. Some data suggest that targeting temperature below normal could benefit select patients where this pathology is common. Clinical temperature management should address the physiology of heat balance. Core temperature reflects the heat content of the head and torso, and changes in core temperature result from changes in the balance of heat production and heat loss. Clinical management of patients after cardiac arrest should include measurement of core temperature at accurate sites and monitoring signs of heat production including shivering. Multiple methods can increase or decrease heat loss, including external and internal devices. Heat loss can trigger compensatory reflexes that increase stress and metabolic demand. Therefore, any active temperature management should include specific pharmacotherapy or other interventions to control thermogenesis, especially shivering. More research is required to determine whether individualized temperature management can improve outcomes.
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Affiliation(s)
- Jonathan Elmer
- Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Clifton W Callaway
- Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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11
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Shaik Mohamed Sayed UF, Moshawih S, Goh HP, Kifli N, Gupta G, Singh SK, Chellappan DK, Dua K, Hermansyah A, Ser HL, Ming LC, Goh BH. Natural products as novel anti-obesity agents: insights into mechanisms of action and potential for therapeutic management. Front Pharmacol 2023; 14:1182937. [PMID: 37408757 PMCID: PMC10318930 DOI: 10.3389/fphar.2023.1182937] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/06/2023] [Indexed: 07/07/2023] Open
Abstract
Obesity affects more than 10% of the adult population globally. Despite the introduction of diverse medications aimed at combating fat accumulation and obesity, a significant number of these pharmaceutical interventions are linked to substantial occurrences of severe adverse events, occasionally leading to their withdrawal from the market. Natural products serve as attractive sources for anti-obesity agents as many of them can alter the host metabolic processes and maintain glucose homeostasis via metabolic and thermogenic stimulation, appetite regulation, pancreatic lipase and amylase inhibition, insulin sensitivity enhancing, adipogenesis inhibition and adipocyte apoptosis induction. In this review, we shed light on the biological processes that control energy balance and thermogenesis as well as metabolic pathways in white adipose tissue browning, we also highlight the anti-obesity potential of natural products with their mechanism of action. Based on previous findings, the crucial proteins and molecular pathways involved in adipose tissue browning and lipolysis induction are uncoupling protein-1, PR domain containing 16, and peroxisome proliferator-activated receptor-γ in addition to Sirtuin-1 and AMP-activated protein kinase pathway. Given that some phytochemicals can also lower proinflammatory substances like TNF-α, IL-6, and IL-1 secreted from adipose tissue and change the production of adipokines like leptin and adiponectin, which are important regulators of body weight, natural products represent a treasure trove for anti-obesity agents. In conclusion, conducting comprehensive research on natural products holds the potential to accelerate the development of an improved obesity management strategy characterized by heightened efficacy and reduced incidence of side effects.
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Affiliation(s)
| | - Said Moshawih
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
| | - Hui Poh Goh
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
| | - Nurolaini Kifli
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
| | - Gaurav Gupta
- School of Pharmacy, Suresh Gyan Vihar University, Jaipur, India
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India
| | - Sachin Kumar Singh
- Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, NSW, Australia
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, India
| | - Dinesh Kumar Chellappan
- Department of Life Sciences, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - Kamal Dua
- Faculty of Health, Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, Ultimo, NSW, Australia
- Discipline of Pharmacy, Graduate School of Health, University of Technology Sydney, Ultimo, NSW, Australia
- Uttaranchal Institute of Pharmaceutical Sciences, Uttaranchal University, Dehradun, India
| | - Andi Hermansyah
- Department of Pharmacy Practice, Faculty of Pharmacy, Universitas AirlanggaSurabaya, Indonesia
| | - Hooi Leng Ser
- School of Medical and Life Sciences, Sunway University, Sunway, Malaysia
| | - Long Chiau Ming
- PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei
- Department of Pharmacy Practice, Faculty of Pharmacy, Universitas AirlanggaSurabaya, Indonesia
- School of Medical and Life Sciences, Sunway University, Sunway, Malaysia
| | - Bey Hing Goh
- Biofunctional Molecule Exploratory Research Group, School of Pharmacy, Monash University Malaysia, Bandar Sunway, Malaysia
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
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12
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Wait SO, Charkoudian N, Skinner JW, Smith CJ. Combining hypoxia with thermal stimuli in humans: physiological responses and potential sex differences. Am J Physiol Regul Integr Comp Physiol 2023; 324:R677-R690. [PMID: 36971421 PMCID: PMC10202487 DOI: 10.1152/ajpregu.00244.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023]
Abstract
Increasing prevalence of native lowlanders sojourning to high altitudes (>2,500 m) for recreational, occupational, military, and competitive reasons has generated increased interest in physiological responses to multistressor environments. Exposure to hypoxia poses recognized physiological challenges that are amplified during exercise and further complicated by environments that might include combinations of heat, cold, and high altitude. There is a sparsity of data examining integrated responses in varied combinations of environmental conditions, with even less known about potential sex differences. How this translates into performance, occupational, and health outcomes requires further investigation. Acute hypoxic exposure decreases arterial oxygen saturation, resulting in a reflex hypoxic ventilatory response and sympathoexcitation causing an increase in heart rate, myocardial contractility, and arterial blood pressure, to compensate for the decreased arterial oxygen saturation. Acute altitude exposure impairs exercise performance, for example, reduced time to exhaustion and slower time trials, largely owing to impairments in pulmonary gas exchange and peripheral delivery resulting in reduced V̇o2max. This exacerbates with increasing altitude, as does the risk of developing acute mountain sickness and more serious altitude-related illnesses, but modulation of those risks with additional stressors is unclear. This review aims to summarize and evaluate current literature regarding cardiovascular, autonomic, and thermoregulatory responses to acute hypoxia, and how these may be affected by simultaneous thermal environmental challenges. There is minimal available information regarding sex as a biological variable in integrative responses to hypoxia or multistressor environments; we highlight these areas as current knowledge gaps and the need for future research.
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Affiliation(s)
- Seaver O Wait
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| | - Nisha Charkoudian
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Jared W Skinner
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| | - Caroline J Smith
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
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13
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Abstract
Brown adipose tissue (BAT) displays the unique capacity to generate heat through uncoupled oxidative phosphorylation that makes it a very attractive therapeutic target for cardiometabolic diseases. Here, we review BAT cellular metabolism, its regulation by the central nervous and endocrine systems and circulating metabolites, the plausible roles of this tissue in human thermoregulation, energy balance, and cardiometabolic disorders, and the current knowledge on its pharmacological stimulation in humans. The current definition and measurement of BAT in human studies relies almost exclusively on BAT glucose uptake from positron emission tomography with 18F-fluorodeoxiglucose, which can be dissociated from BAT thermogenic activity, as for example in insulin-resistant states. The most important energy substrate for BAT thermogenesis is its intracellular fatty acid content mobilized from sympathetic stimulation of intracellular triglyceride lipolysis. This lipolytic BAT response is intertwined with that of white adipose (WAT) and other metabolic tissues, and cannot be independently stimulated with the drugs tested thus far. BAT is an interesting and biologically plausible target that has yet to be fully and selectively activated to increase the body's thermogenic response and shift energy balance. The field of human BAT research is in need of methods able to directly, specifically, and reliably measure BAT thermogenic capacity while also tracking the related thermogenic responses in WAT and other tissues. Until this is achieved, uncertainty will remain about the role played by this fascinating tissue in human cardiometabolic diseases.
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Affiliation(s)
- André C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Denis P Blondin
- Division of Neurology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | | | - Denis Richard
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, G1V 4G5, Canada
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14
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Urlacher SS. The energetics of childhood: Current knowledge and insights into human variation, evolution, and health. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023. [PMID: 36866969 DOI: 10.1002/ajpa.24719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/22/2022] [Accepted: 02/10/2023] [Indexed: 03/04/2023]
Abstract
How organisms capture and ultimately use metabolic energy-a limiting resource of life-has profound implications for understanding evolutionary legacies and current patterns of phenotypic variation, adaptation, and health. Energetics research among humans has a rich history in biological anthropology and beyond. The energetics of childhood, however, remains relatively underexplored. This shortcoming is notable given the accepted importance of childhood in the evolution of the unique human life history pattern as well as the known sensitivity of childhood development to local environments and lived experiences. In this review, I have three objectives: (1) To overview current knowledge regarding how children acquire and use energy, highlighting work among diverse human populations and pointing to recent advances and remaining areas of uncertainty; (2) To discuss key applications of this knowledge for understanding human variation, evolution, and health; (3) To recommend future avenues for research. A growing body of evidence supports a model of trade-offs and constraint in childhood energy expenditure. This model, combined with advancements on topics such as the energetics of immune activity, the brain, and the gut, provides insights into the evolution of extended human subadulthood and the nature of variation in childhood development, lifetime phenotype, and health.
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Affiliation(s)
- Samuel S Urlacher
- Department of Anthropology, Baylor University, Waco, Texas, USA
- Child and Brain Development Program, CIFAR, Toronto, Canada
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15
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Physiological and molecular mechanisms of cold-induced improvements in glucose homeostasis in humans beyond brown adipose tissue. Int J Obes (Lond) 2023; 47:338-347. [PMID: 36774412 DOI: 10.1038/s41366-023-01270-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/26/2023] [Accepted: 01/31/2023] [Indexed: 02/13/2023]
Abstract
Exposure to low ambient temperatures has previously been demonstrated to markedly improve glucose homeostasis in both rodents and humans. Although the brown adipose tissue is key in mediating these beneficial effects in rodents, its contribution appears more limited in humans. Hence, the exact tissues and underlying mechanisms that mediate cold-induced improvements in glucose homeostasis in humans remain to be fully established. In this review, we evaluated the response of the main organs involved in glucose metabolism (i.e. pancreas, liver, (white) adipose tissue, and skeletal muscle) to cold exposure and discuss their potential contribution to cold-induced improvements in glucose homeostasis in humans. We here show that cold exposure has widespread effects on metabolic organs involved in glucose regulation. Nevertheless, cold-induced improvements in glucose homeostasis appear primarily mediated via adaptations within the skeletal muscle and (presumably) white adipose tissue. Since the underlying mechanisms remain elusive, future studies should be aimed at pinpointing the exact physiological and molecular mechanisms involved in humans. Nonetheless, cold exposure holds great promise as a novel, additive lifestyle approach to improve glucose homeostasis in insulin resistant individuals. Parts of this graphical abstract were created using (modified) images from Servier Medical Art, licensed under the Creative Commons Attribution 3.0 Unported License. TG = thermogenesis, TAG = triacylglycerol, FFA = free fatty acid, SLN = sarcolipin, UCP3 = uncoupling protein 3, β2-AR = beta-2 adrenergic receptor, SNS = sympathetic nervous system.
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16
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Biomarkers for warfighter safety and performance in hot and cold environments. J Sci Med Sport 2022:S1440-2440(22)00503-5. [PMID: 36623995 DOI: 10.1016/j.jsams.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 12/06/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Exposure to extreme environmental heat or cold during military activities can impose severe thermal strain, leading to impairments in task performance and increasing the risk of exertional heat (including heat stroke) and cold injuries that can be life-threatening. Substantial individual variability in physiological tolerance to thermal stress necessitates an individualized approach to mitigate the deleterious effects of thermal stress, such as physiological monitoring of individual thermal strain. During heat exposure, measurements of deep-body (Tc) and skin temperatures and heart rate can provide some indication of thermal strain. Combining these physiological variables with biomechanical markers of gait (in)stability may provide further insight on central nervous system dysfunction - the key criterion of exertional heat stroke (EHS). Thermal strain in cold environments can be monitored with skin temperature (peripheral and proximal), shivering thermogenesis and Tc. Non-invasive methods for real-time estimation of Tc have been developed and some appear to be promising but require further validation. Decision-support tools provide useful information for planning activities and biomarkers can be used to improve their predictions, thus maximizing safety and performance during hot- and cold-weather operations. With better understanding on the etiology and pathophysiology of EHS, the microbiome and markers of the inflammatory responses have been identified as novel biomarkers of heat intolerance. This review aims to (i) discuss selected physiological and biomechanical markers of heat or cold strain, (ii) how biomarkers may be used to ensure operational readiness in hot and cold environments, and (iii) present novel molecular biomarkers (e.g., microbiome, inflammatory cytokines) for preventing EHS.
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17
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Sellers AJ, Khovalyg D, Plasqui G, van Marken Lichtenbelt W. High daily energy expenditure of Tuvan nomadic pastoralists living in an extreme cold environment. Sci Rep 2022; 12:20127. [PMID: 36418413 PMCID: PMC9684425 DOI: 10.1038/s41598-022-23975-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/08/2022] [Indexed: 11/24/2022] Open
Abstract
Research investigating thermoregulatory energy costs in free-living humans is limited. We determined the total energy expenditure (TEE) of Tuvan pastoralists living in an extreme cold environment and explored the contribution of physical activity and cold-induced thermogenesis. Twelve semi-nomadic pastoralists (47 ± 8 years, 64 ± 8 kg) living under traditional circumstances, in Tuva, south-central Siberia, Russia, were observed during two consecutive 6-day periods in winter. TEE was measured via the doubly labelled water technique. Skin and ambient temperatures, and physical activity were continuously monitored. The outdoor temperature during the observation period was - 27.4 ± 5.4 °C. During the daytime, the participants were exposed to ambient temperatures below 0 °C for 297 ± 131 min/day. The Tuvan pastoralists were more physically active compared to western populations (609 ± 90 min/day of light, moderate, and vigorous physical activity). In addition, TEE was 13.49 ± 1.33 MJ/day (3224 ± 318 kcal/day), which was significantly larger by 17% and 31% than predicted by body mass, and fat-free mass, respectively. Our research suggests the daily cold exposure combined with high levels of physical activity contributed to the elevated TEE. Future research should reconsider the assumption that energy costs due to thermoregulation are negligible in free-living humans.
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Affiliation(s)
- Adam J. Sellers
- grid.5012.60000 0001 0481 6099Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Dolaana Khovalyg
- grid.5333.60000000121839049Laboratory of Integrated Comfort Engineering (ICE), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Guy Plasqui
- grid.5012.60000 0001 0481 6099Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Wouter van Marken Lichtenbelt
- grid.5012.60000 0001 0481 6099Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
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18
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Ahmed SG, S.R. S. Analysis of human thermoregulatory mechanisms using 2-D computational model. J Therm Biol 2022; 110:103388. [DOI: 10.1016/j.jtherbio.2022.103388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/30/2022] [Accepted: 11/03/2022] [Indexed: 11/10/2022]
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19
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DeGroot DW, O'Connor FG, Roberts WO. Exertional heat stroke: An evidence based approach to clinical assessment and management. Exp Physiol 2022; 107:1172-1183. [PMID: 35771080 DOI: 10.1113/ep090488] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/06/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? The treatment of exertional heat stress, from initial field care through the return-to-activity decision, is reviewed. What advances does it highlight? Clinical assessment during field care using AVPU and vital signs to gauge recovery Approaches to field cooling and end of active cooling Shared clinical decision making for return to activity recommendations ABSTRACT: Exertional heat stroke (EHS) is a potentially fatal condition characterized by central nervous system dysfunction and body temperature often but not always >40°C that occurs in the context of physical work in warm or hot environments. In this paper, we review the continuum of care, from initial recognition and field care to transport and hospital care, and finally return to duty considerations. Morbidity and mortality can be greatly reduced if not eliminated with prompt recognition and aggressive cooling. If medical personnel are not present at point of collapse during or immediately following exercise, EHS should be the presumptive diagnosis until a formal diagnosis can be determined by qualified medical staff. EHS is the rare medical situation where initial treatment (cooling) takes precedence over transport to a medical facility, where advanced medical care may be required for severe EHS casualties. Recovery from EHS and return to activity is usually straightforward and unremarkable provided the casualty is rapidly cooled at time of collapse and adequate time is allowed for body healing. However, evidence-based data to guide return to activity following EHS is limited. Current research suggests that most individuals recover completely within a few weeks though some individuals may suffer prolonged sequalae and additional evaluation may be warranted, including heat tolerance testing. Several aspects of the care of the EHS casualty are based on best practices derived from personal experience and continued research is necessary to optimize evaluation and management. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Francis G O'Connor
- Department of Military and Emergency Medicine, Uniformed Services University, Bethesda, MD, USA
| | - William O Roberts
- Department of Family Medicine and Community Health, University of Minnesota Medical School, Minneapolis, MN, USA
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20
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Haman F, Souza SCS, Castellani JW, Dupuis MP, Friedl KE, Sullivan-Kwantes W, Kingma BRM. Human vulnerability and variability in the cold: Establishing individual risks for cold weather injuries. Temperature (Austin) 2022; 9:158-195. [PMID: 36106152 PMCID: PMC9467591 DOI: 10.1080/23328940.2022.2044740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 01/08/2023] Open
Abstract
Human tolerance to cold environments is extremely limited and responses between individuals is highly variable. Such physiological and morphological predispositions place them at high risk of developing cold weather injuries [CWI; including hypothermia and/or non-freezing (NFCI) and freezing cold injuries (FCI)]. The present manuscript highlights current knowledge on the vulnerability and variability of human cold responses and associated risks of developing CWI. This review 1) defines and categorizes cold stress and CWI, 2) presents cold defense mechanisms including biological adaptations, acute responses and acclimatization/acclimation and, 3) proposes mitigation strategies for CWI. This body of evidence clearly indicates that all humans are at risk of developing CWI without adequate knowledge and protective equipment. In addition, we show that while body mass plays a key role in mitigating risks of hypothermia between individuals and populations, NFCI and FCI depend mainly on changes in peripheral blood flow and associated decrease in skin temperature. Clearly, understanding the large interindividual variability in morphology, insulation, and metabolism is essential to reduce potential risks for CWI between and within populations.
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Affiliation(s)
- François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa,Ontario, Canada
| | - Sara C. S. Souza
- Faculty of Health Sciences, University of Ottawa, Ottawa,Ontario, Canada
| | - John W. Castellani
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Maria-P. Dupuis
- Faculty of Health Sciences, University of Ottawa, Ottawa,Ontario, Canada
| | - Karl E. Friedl
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Wendy Sullivan-Kwantes
- Biophysics and Biomedical Modeling Division, Defence Research Development Canada-Toronto, Defence Research and Development Canada, Ontario, Canada
| | - Boris R. M. Kingma
- Netherlands Organization for Applied Scientific Research, Department of Human Performance, Unit Defence, Safety and Security, Soesterberg, The Netherlands
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21
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Vogel K, Hulsopple C. Cold Weather Injuries: Initial Evaluation and Management. Curr Sports Med Rep 2022; 21:117-122. [PMID: 35394952 DOI: 10.1249/jsr.0000000000000947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT As more people take to extreme sporting activities and hobbies, the sports medicine physician should be proficient in early identification and initial sideline or field management of cold weather injuries. There is significant mortality and morbidity associated with these conditions. The most severe of these are hypothermia and frostbite, which have limited evidence for their field management. Nonfreezing cold injuries and chilblains are much rarer, although appropriate prevention and treatment strategies can be used to minimize harm to athletes. This article will provide the most updated recommendations for field or sideline evaluation and initial management of hypothermia, frostbite, nonfreezing cold injury, and chilblains.
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Affiliation(s)
- Kendall Vogel
- 23d Operational Medical Readiness Squadron Medical Group, Moody AFB, G
| | - Chad Hulsopple
- Department of Family Medicine, Uniformed Services University, Bethesda, MD
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22
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Diurnal variations of cold-induced thermogenesis in young, healthy adults: A randomized crossover trial. Clin Nutr 2021; 40:5311-5321. [PMID: 34536639 DOI: 10.1016/j.clnu.2021.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/04/2021] [Accepted: 08/16/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND Harnessing cold-induced thermogenesis (CIT) and brown adipose tissue (BAT) activity has been proposed as a means of counteracting a positive energy balance, and thus of combating obesity and its related comorbidities. However, it has remained unclear whether CIT and BAT activity show diurnal variation in humans - knowledge that might allow treatments based on these factors to be time-optimized. METHODS A randomized crossover experiment was designed to examine whether CIT shows morning/evening variation in young, healthy adults (n = 14, 5 women). On the first experimental day, subjects' shivering thresholds were determined following a cooling protocol. After ≈96 h had elapsed, the subjects then returned on two further days (approx. 48 h apart) at 08:00 h or 18:00 in random order. On both the latter days, the resting energy expenditure (REE) was measured before the subjects underwent personalized cold exposure (i.e., according to their shivering threshold). CIT was then assessed for 60 min by indirect calorimetry. In an independent cross-sectional study (n = 133, 88 women), subjects came to the laboratory between 8:00 and 18:00 h and their BAT 18F-fluordeoxyglucose (18F-FDG) uptake was assessed after personalized cold stimulation. RESULTS Both the REE and CIT were similar in the morning and evening (all P > 0.05). Indeed, 60 min of personalized-mild cold exposure in the morning or evening elicited a similar change in energy expenditure (16.8 ± 12.8 vs. 15.7 ± 15.1% increase above REE, P = 0.72). BAT 18F-FDG uptake was also similar in the morning, evening and afternoon (all P > 0.05). CONCLUSION CIT does not appear to show morning/evening variation in young healthy adults, with the current study design and methodology. BAT 18F-FDG uptake appears not to change across the day either, although experiments with a within-subject study design are needed to confirm these findings. Registered under ClinicalTrials.gov Identifier no. NCT02365129.
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23
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Greenfield AM, Charkoudian N, Alba BK. Influences of ovarian hormones on physiological responses to cold in women. Temperature (Austin) 2021; 9:23-45. [DOI: 10.1080/23328940.2021.1953688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Andrew Martin Greenfield
- Thermal & Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA
- Oak Ridge Institute of Science and Education, Belcamp, MD, USA
| | - Nisha Charkoudian
- Thermal & Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Billie Katherine Alba
- Thermal & Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA
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24
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Krapf S, Schjølberg T, Asoawe L, Honkanen SK, Kase ET, Thoresen GH, Haugen F. Novel methods for cold exposure of skeletal muscle in vivo and in vitro show temperature-dependent myokine production. J Therm Biol 2021; 98:102930. [PMID: 34016352 DOI: 10.1016/j.jtherbio.2021.102930] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 03/17/2021] [Accepted: 03/29/2021] [Indexed: 11/29/2022]
Abstract
Proteins secreted from skeletal muscle serving a signalling role have been termed myokines. Many of the myokines are exercise factors, produced and released in response to muscle activity. Cold exposures affecting muscle may occur in recreational, occupational and therapeutic settings. Whether muscle temperature independently affects myokine profile, is still to be elucidated. We hypothesized that manipulating muscle temperature by means of external cooling would change myokine production and release. In the present study we have established new models for cold exposure of muscle in vivo and in vitro where rat hind limb or cultured human myotubes were cooled to 18 °C. After a recovery period, muscle tissue, cells and culture media were harvested for further analysis by qPCR and immunoassays. Expression of several myokine genes were significantly increased after cold exposure in both models: in rat muscle, mRNA levels of CCL2 (p = 0.04), VEGFA (p = 0.02), CXCL1 (p = 0.02) and RBM3 (p = 0.02) increased while mRNA levels of IL-6 (p = 0.03) were decreased; in human myotubes, mRNA levels of IL6 (p = 0.01), CXCL8 (p = 0.04), VEGFA (p = 0.03) and CXCL1 (p < 0.01) were significantly increased, as well as intracellular protein levels of IL-8 (CXCL8 gene product; p < 0.01). The corresponding effect on myokine secretion was not observed, on the contrary, IL-8 (p = 0.02) and VEGF (VEGFA gene product) p < 0.01) concentrations in culture media were reduced after cold exposure in vitro. In conclusion, cold exposure of muscle in vivo and in vitro had an effect on the production and release of several known exercise-related myokines. Myokine expression at the level of mRNA and protein was increased by cold exposure, whereas secretion tended to be decreased.
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Affiliation(s)
- Solveig Krapf
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | | | - Lucia Asoawe
- National Institute of Occupational Health, Oslo, Norway
| | | | - Eili Tranheim Kase
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - G Hege Thoresen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway; Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Fred Haugen
- National Institute of Occupational Health, Oslo, Norway.
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Rodríguez J, Willmes C, Mateos A. Shivering in the Pleistocene. Human adaptations to cold exposure in Western Europe from MIS 14 to MIS 11. J Hum Evol 2021; 153:102966. [PMID: 33711721 DOI: 10.1016/j.jhevol.2021.102966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 12/30/2022]
Abstract
During the mid-Middle Pleistocene MIS 14 to MIS 11, humans spread through Western Europe from the Mediterranean peninsulas to the sub-Arctic region, and they did so not only during the warm periods but also during the glacial stages. In doing so, they were exposed to harsh environmental conditions, including low or extremely low temperatures. Here we review the distribution of archeological assemblages in Western Europe from MIS 14 to MIS 11 and obtain estimates of the climatic conditions at those localities. Estimates of the mean annual temperature, mean winter and summer temperatures, and the lowest temperature of the coldest month for each locality were obtained from the Oscillayers database. Our results show that hominins endured cold exposure not only during the glacial stages but also during the interglacials, with winter temperatures below 0 °C at many localities. The efficacy of the main physiological and behavioral adaptations that might have been used by the Middle Pleistocene hominins to cope with low temperatures is evaluated using a simple heat-loss model. Our results suggest that physiological and anatomical adaptations alone, such as increasing basal metabolic rate and subcutaneous adipose tissue, were not enough to tolerate the low winter temperatures of Western Europe, even during the MIS 13 and MIS 11 interglacials. In contrast, the use of a simple fur bed cover appears to have been an extremely effective response to low temperatures. We suggest that advanced fire production and control technology were not necessary for the colonization of northern Europe during MIS 14 and MIS 12. We propose that Middle Pleistocene European populations were able to endure the low temperatures of those glacial stages combining anatomical and physiological adaptations with behavioral responses, such as the use of shelter and simple fur clothes.
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Affiliation(s)
- Jesús Rodríguez
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain
| | - Christian Willmes
- Institute of Geography, University of Cologne, 50923, Cologne, Germany
| | - Ana Mateos
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain.
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Arnold JT, Bailey SJ, Hodder SG, Fujii N, Lloyd AB. Independent and combined impact of hypoxia and acute inorganic nitrate ingestion on thermoregulatory responses to the cold. Eur J Appl Physiol 2021; 121:1207-1218. [PMID: 33558988 PMCID: PMC7966143 DOI: 10.1007/s00421-021-04602-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/10/2021] [Indexed: 11/28/2022]
Abstract
Purpose This study assessed the impact of normobaric hypoxia and acute nitrate ingestion on shivering thermogenesis, cutaneous vascular control, and thermometrics in response to cold stress. Method Eleven male volunteers underwent passive cooling at 10 °C air temperature across four conditions: (1) normoxia with placebo ingestion, (2) hypoxia (0.130 FiO2) with placebo ingestion, (3) normoxia with 13 mmol nitrate ingestion, and (4) hypoxia with nitrate ingestion. Physiological metrics were assessed as a rate of change over 45 min to determine heat loss, and at the point of shivering onset to determine the thermogenic thermoeffector threshold. Result Independently, hypoxia expedited shivering onset time (p = 0.05) due to a faster cooling rate as opposed to a change in central thermoeffector thresholds. Specifically, compared to normoxia, hypoxia increased skin blood flow (p = 0.02), leading to an increased core-cooling rate (p = 0.04) and delta change in rectal temperature (p = 0.03) over 45 min, yet the same rectal temperature at shivering onset (p = 0.9). Independently, nitrate ingestion delayed shivering onset time (p = 0.01), mediated by a change in central thermoeffector thresholds, independent of changes in peripheral heat exchange. Specifically, compared to placebo ingestion, no difference was observed in skin blood flow (p = 0.5), core-cooling rate (p = 0.5), or delta change in rectal temperature (p = 0.7) over 45 min, while nitrate reduced rectal temperature at shivering onset (p = 0.04). No interaction was observed between hypoxia and nitrate ingestion. Conclusion These data improve our understanding of how hypoxia and nitric oxide modulate cold thermoregulation.
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Affiliation(s)
- Josh T Arnold
- Environmental Ergonomics Research Centre, James France Bldg, Design School, Loughborough University, Loughborough, LE11 3TU, UK
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Simon G Hodder
- Environmental Ergonomics Research Centre, James France Bldg, Design School, Loughborough University, Loughborough, LE11 3TU, UK
| | - Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Alex B Lloyd
- Environmental Ergonomics Research Centre, James France Bldg, Design School, Loughborough University, Loughborough, LE11 3TU, UK.
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Sellers AJ, Pallubinsky H, Rense P, Bijnens W, van de Weijer T, Moonen-Kornips E, Schrauwen P, van Marken Lichtenbelt WD. The effect of cold exposure with shivering on glucose tolerance in healthy men. J Appl Physiol (1985) 2021; 130:193-205. [DOI: 10.1152/japplphysiol.00642.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
This is the first study to examine the effect of cold-induced shivering on subsequent glucose tolerance determined under thermoneutral conditions. Plasma glucose and insulin concentrations increased during the oral glucose tolerance test post shivering. Additionally, insulin sensitivity indices suggest insulin resistance following cold exposure. These results provide evidence for an acute post-shivering response, whereby glucose metabolism has deteriorated, contrary to the results from earlier studies on cold acclimation.
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Affiliation(s)
- Adam Jake Sellers
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Hannah Pallubinsky
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Pascal Rense
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Wouter Bijnens
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Tineke van de Weijer
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Esther Moonen-Kornips
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Wouter D. van Marken Lichtenbelt
- Department of Nutrition and Movement Sciences, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
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Keramidas ME, Kölegård R, Eiken O. Hypoxia gradually augments metabolic and thermoperceptual responsiveness to repeated whole-body cold stress in humans. Exp Physiol 2020; 105:2123-2140. [PMID: 33140429 PMCID: PMC7756580 DOI: 10.1113/ep089070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 10/30/2020] [Indexed: 12/02/2022]
Abstract
New Findings What is the central question of this study? In male lowlanders, does hypoxia modulate thermoregulatory effector responses during repeated whole‐body cold stress encountered in a single day? What is the main finding and its importance? A ∼10 h sustained exposure to hypoxia appears to mediate a gradual upregulation of endogenous heat production, preventing the progressive hypothermic response prompted by serial cold stimuli. Also, hypoxia progressively degrades mood, and compounds the perceived thermal discomfort, and sensations of fatigue and coldness.
Abstract We examined whether hypoxia would modulate thermoeffector responses during repeated cold stress encountered in a single day. Eleven men completed two ∼10 h sessions, while breathing, in normobaria, either normoxia or hypoxia (PO2: 12 kPa). During each session, subjects underwent sequentially three 120 min immersions to the chest in 20°C water (CWI), interspersed by 120 min rewarming. In normoxia, the final drop in rectal temperature (Trec) was greater in the third (∼1.2°C) than in the first and second (∼0.9°C) CWIs (P < 0.05). The first hypoxic CWI augmented the Trec fall (∼1.2°C; P = 0.002), but the drop in Trec did not vary between the three hypoxic CWIs (P = 0.99). In normoxia, the metabolic heat production (M˙) was greater during the first half of the third CWI than during the corresponding part of the first CWI (P = 0.02); yet the difference was blunted during the second half of the CWIs (P = 0.89). In hypoxia, by contrast, the increase in M˙ was augmented by ∼25% throughout the third CWI (P < 0.01). Regardless of the breathing condition, the cold‐induced elevation in mean arterial pressure was blunted in the second and third CWI (P < 0.05). Hypoxia aggravated the sensation of coldness (P = 0.05) and thermal discomfort (P = 0.04) during the second half of the third CWI. The present findings therefore demonstrate that prolonged hypoxia mediates, in a gradual manner, metabolic and thermoperceptual sensitization to repeated cold stress.
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Affiliation(s)
- Michail E Keramidas
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Roger Kölegård
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ola Eiken
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
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Mugele H, Oliver SJ, Gagnon D, Lawley JS. Integrative crosstalk between hypoxia and the cold: Old data and new opportunities. Exp Physiol 2020; 106:350-358. [DOI: 10.1113/ep088512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/25/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Hendrik Mugele
- Department of Sport Science University of Innsbruck Innsbruck Austria
| | - Samuel J. Oliver
- Extremes Research Group School of Sport, Health and Exercise Sciences Bangor University Wales UK
| | - Daniel Gagnon
- Cardiovascular Prevention and Rehabilitation Centre Montreal Heart Institute Montréal Quebec Canada
- Department of Pharmacology and Physiology Faculty of Medicine Université de Montréal Montréal Quebec Canada
| | - Justin S. Lawley
- Department of Sport Science University of Innsbruck Innsbruck Austria
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Yau WW, Yen PM. Thermogenesis in Adipose Tissue Activated by Thyroid Hormone. Int J Mol Sci 2020; 21:ijms21083020. [PMID: 32344721 PMCID: PMC7215895 DOI: 10.3390/ijms21083020] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/19/2020] [Accepted: 04/22/2020] [Indexed: 02/07/2023] Open
Abstract
Thermogenesis is the production of heat that occurs in all warm-blooded animals. During cold exposure, there is obligatory thermogenesis derived from body metabolism as well as adaptive thermogenesis through shivering and non-shivering mechanisms. The latter mainly occurs in brown adipose tissue (BAT) and muscle; however, white adipose tissue (WAT) also can undergo browning via adrenergic stimulation to acquire thermogenic potential. Thyroid hormone (TH) also exerts profound effects on thermoregulation, as decreased body temperature and increased body temperature occur during hypothyroidism and hyperthyroidism, respectively. We have termed the TH-mediated thermogenesis under thermoneutral conditions “activated” thermogenesis. TH acts on the brown and/or white adipose tissues to induce uncoupled respiration through the induction of the uncoupling protein (Ucp1) to generate heat. TH acts centrally to activate the BAT and browning through the sympathetic nervous system. However, recent studies also show that TH acts peripherally on the BAT to directly stimulate Ucp1 expression and thermogenesis through an autophagy-dependent mechanism. Additionally, THs can exert Ucp1-independent effects on thermogenesis, most likely through activation of exothermic metabolic pathways. This review summarizes thermogenic effects of THs on adipose tissues.
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Affiliation(s)
- Winifred W Yau
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders Program, Duke NUS Medical School, Singapore 169857, Singapore
| | - Paul M Yen
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders Program, Duke NUS Medical School, Singapore 169857, Singapore
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27708, USA
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Grundlagen der Volumetrischen Kapnographie. Anaesthesist 2020; 69:287-296. [DOI: 10.1007/s00101-020-00744-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Xu J, Yu X, Zhang L, Fu Y, Jin K, Yin L, Yu S, Liu D. Modified volumetric capnography-derived parameter: A potentially stable indicator in monitoring cardiopulmonary resuscitation efficacy in a porcine model. Resuscitation 2020; 150:94-101. [PMID: 32220582 DOI: 10.1016/j.resuscitation.2020.02.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 02/22/2020] [Accepted: 02/29/2020] [Indexed: 11/26/2022]
Abstract
AIM We aimed to investigate whether the ability of the volumetric capnography-derived parameter, the volume of CO2 eliminated per minute and per kg body weight (V'CO2 kg-1), in monitoring the quality of CPR and predicting the return of spontaneous circulation (ROSC) remains undisturbed by hyperventilation. METHODS This randomised crossover study included 12 male domestic pigs. After 4 min of untreated ventricular fibrillation, mechanical CPR was administered. Following 5-min washout periods, each animal underwent two sessions of experiments; four 5-min ventilation trials followed by advanced life support, consecutively in the two sessions. RESULTS Different ventilation types had no significant impact on V'CO2 kg-1 or haemodynamics. However, PETCO2 was significantly affected by the ventilation type and coronary perfusion pressure (P < 0.05). The means ± standard deviations of PETCO2 decreased linearly with an increase in the respiratory rate (RR) (P < 0.05). The PETCO2 decreased from 20.42 ± 9.51 to 16.16 ± 5.07 (P < 0.05) as the tidal volume increased from 10 to 20 mL min-1. No significant differences in V'CO2 kg-1 were observed between the three RR levels of ventilation types (P = 0.274). Post hoc analysis demonstrated a significant difference between the highest value of V'CO2 kg-1 in double tidal volume hyperventilation and normal ventilation and triple respiratory rate hyperventilation (P < 0.05). The AUC for V'CO2 kg-1 and PETCO2 in discriminating between survivors and non-survivors was 0.80 and 0.71, respectively. CONCLUSIONS V'CO2 kg-1 performs better than PETCO2 in monitoring the quality of CPR during hyperventilation. In predicting ROSC during variations in a ventilation state, V'CO2 kg-1 has good predictive ability.
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Affiliation(s)
- Jun Xu
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
| | - Xuezhong Yu
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
| | - Lili Zhang
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Yangyang Fu
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Kui Jin
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Lu Yin
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Shanshan Yu
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Danyu Liu
- Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
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Reliability and validity of methods in the assessment of cold-induced shivering thermogenesis. Eur J Appl Physiol 2020; 120:591-601. [PMID: 31955279 PMCID: PMC7042274 DOI: 10.1007/s00421-019-04288-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 12/11/2019] [Indexed: 01/04/2023]
Abstract
PURPOSE To compare two analytical methods for the estimation of the shivering onset inflection point, segmental regression and visual inspection of data, and to assess the test-retest reliability and validity of four metrics of shivering measurement; oxygen uptake (V̇O2), electromyography (EMG), mechanomyography (MMG) and bedside shivering assessment scale (BSAS). METHODS Ten volunteers attended three identical experimental sessions involving passive deep-body cooling via cold water immersion at 10 °C. V̇O2, EMG, and MMG were continuously assessed, while the time elapsed at each BSAS stage was recorded. Metrics were graphed as a function of time and rectal temperature (Tre). Inflection points for intermittent and constant shivering were visually identified for every graph and compared to segmental regression. RESULTS Excellent agreement was seen between segmental regression and visual inspection (ICC, 0.92). All measurement metrics presented good-to-excellent test-retest reliability (ICC's > 0.75 and 0.90 respectively), with the exception of visual identification of intermittent shivering for V̇O2 measurement (ICC, 0.73) and segmental regression for EMG measurement (ICC, 0.74). In the assessment of signal-to-noise ratio (SNR), EMG showed the largest SNR at the point of shivering onset followed by MMG and finally V̇O2. CONCLUSIONS Segmental regression provides a successful analytical method for identifying shivering onset. Good-to-excellent reliability can be seen across V̇O2, EMG, MMG, and BSAS, yet given the observed lag times, SNRs, along with known advantages/disadvantaged of each metric, it is recommended that no single metric is used in isolation. An integrative, real-time measure of shivering is proposed.
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Chen KY, Brychta RJ, Abdul Sater Z, Cassimatis TM, Cero C, Fletcher LA, Israni NS, Johnson JW, Lea HJ, Linderman JD, O'Mara AE, Zhu KY, Cypess AM. Opportunities and challenges in the therapeutic activation of human energy expenditure and thermogenesis to manage obesity. J Biol Chem 2019; 295:1926-1942. [PMID: 31914415 DOI: 10.1074/jbc.rev119.007363] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The current obesity pandemic results from a physiological imbalance in which energy intake chronically exceeds energy expenditure (EE), and prevention and treatment strategies remain generally ineffective. Approaches designed to increase EE have been informed by decades of experiments in rodent models designed to stimulate adaptive thermogenesis, a long-term increase in metabolism, primarily induced by chronic cold exposure. At the cellular level, thermogenesis is achieved through increased rates of futile cycling, which are observed in several systems, most notably the regulated uncoupling of oxidative phosphorylation from ATP generation by uncoupling protein 1, a tissue-specific protein present in mitochondria of brown adipose tissue (BAT). Physiological activation of BAT and other organ thermogenesis occurs through β-adrenergic receptors (AR), and considerable effort over the past 5 decades has been directed toward developing AR agonists capable of safely achieving a net negative energy balance while avoiding unwanted cardiovascular side effects. Recent discoveries of other BAT futile cycles based on creatine and succinate have provided additional targets. Complicating the current and developing pharmacological-, cold-, and exercise-based methods to increase EE is the emerging evidence for strong physiological drives toward restoring lost weight over the long term. Future studies will need to address technical challenges such as how to accurately measure individual tissue thermogenesis in humans; how to safely activate BAT and other organ thermogenesis; and how to sustain a negative energy balance over many years of treatment.
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Affiliation(s)
- Kong Y Chen
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
| | - Robert J Brychta
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Zahraa Abdul Sater
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Thomas M Cassimatis
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Cheryl Cero
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Laura A Fletcher
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Nikita S Israni
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - James W Johnson
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Hannah J Lea
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Joyce D Linderman
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Alana E O'Mara
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Kenneth Y Zhu
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Aaron M Cypess
- Diabetes, Endocrinology, and Obesity Branch, Intramural Research Program, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
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Lupo BL, Collins SB, Hewer I, Hooper VD. Comparing Forced-Air to Resistive-Polymer Warming for Perioperative Temperature Management: A Retrospective Study. J Perianesth Nurs 2019; 35:178-184. [PMID: 31859207 DOI: 10.1016/j.jopan.2019.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 08/06/2019] [Accepted: 08/19/2019] [Indexed: 11/18/2022]
Abstract
PURPOSE Compare perioperative temperature management between forced-air warming (FAW) and resistive-polymer heating blankets (RHBs). DESIGN A retrospective, quasi-experimental study. METHODS Retrospective data analysis of nonspine orthopedic cases (N = 426) over a one-year period including FAW (n = 119) and RHBs (n = 307). FINDINGS FAW was associated with a significantly higher final intraoperative temperature (P = .001, d = 0.46) than the RHB. The incidence of hypothermia was not found to be significantly different at the end (P = .102) or anytime throughout surgery (P = .270). Of all patients who started hypothermic, the FAW group had a lower incidence of hypothermia at the end of surgery (P = .023). CONCLUSIONS FAW was associated with higher final temperatures and a greater number of normothermic patients than RHBs. However, no causal relationship between a warming device and hypothermia incidence should be assumed.
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Affiliation(s)
| | | | - Ian Hewer
- Western Carolina University, School of Nursing, Asheville, NC
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Manolis AS, Manolis SA, Manolis AA, Manolis TA, Apostolaki N, Melita H. Winter Swimming. Curr Sports Med Rep 2019; 18:401-415. [DOI: 10.1249/jsr.0000000000000653] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Brychta RJ, Huang S, Wang J, Leitner BP, Hattenbach JD, Bell SL, Fletcher LA, Perron Wood R, Idelson CR, Duckworth CJ, McGehee S, Courville AB, Bernstein SB, Reitman ML, Cypess AM, Chen KY. Quantification of the Capacity for Cold-Induced Thermogenesis in Young Men With and Without Obesity. J Clin Endocrinol Metab 2019; 104:4865-4878. [PMID: 31150063 PMCID: PMC6733495 DOI: 10.1210/jc.2019-00728] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/24/2019] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Cold exposure increases energy expenditure (EE) and could have a role in combating obesity. To understand this potential, we determined the capacity for cold-induced thermogenesis (CIT), the EE increase above the basal metabolic rate at the individualized coldest tolerable temperature before overt shivering. DESIGN During a 13-day inpatient protocol, we quantitated the EE of 12 lean men and 9 men with obesity at various randomly ordered ambient temperatures in a room calorimeter. Subjects underwent brown fat imaging after exposure to their coldest tolerable temperature. RESULTS CIT capacity was 300 ± 218 kcal/d (mean ± SD) or 17 ± 11% in lean men and 125 ± 146 kcal/d or 6 ± 7% in men with obesity (P = 0.01). The temperature below which EE increased, lower critical temperature (Tlc), was warmer in lean men than men with obesity (22.9 ± 1.2 vs 21.1 ± 1.7°C, P = 0.03), but both had similar skin temperature (Tskin) changes and coldest tolerable temperatures. Whereas lean subjects had higher brown fat activity, skeletal muscle activity increased synchronously with CIT beginning at the Tlc in both groups, indicating that muscle is recruited for CIT in parallel with brown fat, not sequentially after nonshivering thermogenesis is maximal. CONCLUSIONS Despite greater insulation from fat, men with obesity had a narrower range of tolerable cool temperatures available for increasing EE and less capacity for CIT than lean men, likely as a result of greater basal heat production and similar perception to Tskin cooling. Further study of the reduced CIT capacity in men with obesity may inform treatment opportunities for obesity.
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Affiliation(s)
- Robert J Brychta
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
- Correspondence and Reprint Requests: Robert J. Brychta, PhD, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10 Center Drive, Building 10, Room 5-5740, Bethesda, Maryland 20892. E-mail:
| | - Shan Huang
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Juan Wang
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Brooks P Leitner
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Jacob D Hattenbach
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sarah L Bell
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Laura A Fletcher
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Rachel Perron Wood
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Christopher R Idelson
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Courtney J Duckworth
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Suzanne McGehee
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Amber B Courville
- Nutrition Department, Hatfield Clinical Research Center, National Institutes of Health, Bethesda, Maryland
| | - Shanna B Bernstein
- Nutrition Department, Hatfield Clinical Research Center, National Institutes of Health, Bethesda, Maryland
| | - Marc L Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Aaron M Cypess
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Kong Y Chen
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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Wada K, Masamune T, Ino H, Ueda K, Ishiyama T, Sessler DI, Matsukawa T. Severe hypoglycemia reduces the shivering threshold in rabbits. BMC Anesthesiol 2019; 19:126. [PMID: 31288741 PMCID: PMC6617602 DOI: 10.1186/s12871-019-0794-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 06/27/2019] [Indexed: 11/16/2022] Open
Abstract
Background We previously reported that each 100 mg dL− 1 reduction in blood glucose over the range from ≈90 to > 300 mg dL− 1 decreases the shivering threshold (triggering core temperature) in rabbits by 1 °C. However, the effects of lower blood glucose concentrations has yet to be evaluated. We thus evaluated the relationship between the shivering threshold and blood glucose concentration over the mild-to-severe hypoglycemic range. Methods Thirty-nine rabbits were lightly anaesthetized with isoflurane and randomly assigned to one of the three groups: 1) severe hypoglycemia, insulin and dextrose infusions titrated to achieve blood glucose concentration at 45–75 mg dL− 1; 2) mild hypoglycemia, insulin and dextrose infusions titrated to achieve blood glucose concentration at 75–100 mg dL− 1; and 3) saline infusion. Cooling by colonic perfusion of water at 10 °C was continued until shivering occurred or esophageal core temperatures reached to 34 °C. Results The shivering threshold in the severe hypoglycemic rabbits was 35.7 ± 1.1 °C (mean ± SD); the thresholds in the mild hypoglycemic rabbits was 37.0 ± 0.7 °C; and the threshold in the control rabbits was 37.9 ± 1.0 °C. The shivering threshold increased linearly with blood glucose concentration: shivering threshold (°C) = 0.032 ∙ [blood glucose concentration (mg dL− 1)] + 34.1, R2 = 0.45. The shivering threshold thus decreased by approximately 1 °C for each 31 mg dL− 1 decrease in blood glucose concentration. Conclusions There was a linear relationship between blood glucose and the shivering threshold over the range from severe hypoglycemia to normoglycemia. Blood glucose perturbations in the hypoglycemic range reduced the shivering threshold about three times as much as previously reported for the hyperglycemic range.
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Affiliation(s)
- Keiichi Wada
- Surgical Center, University of Yamanashi Hospital, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
| | - Taishi Masamune
- Department of Anesthesia, Yamanashi Prefectural Central Hospital, Kofu, Japan
| | - Hirofumi Ino
- Department of Anesthesiology, University of Yamanashi, Chuo, Japan
| | - Kenta Ueda
- Department of Anesthesiology, University of Yamanashi, Chuo, Japan
| | - Tadahiko Ishiyama
- Surgical Center, University of Yamanashi Hospital, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - Daniel I Sessler
- Department of Outcomes Research, Anesthesiology Institute, Clinic, Cleveland, USA
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Palmer BF, Clegg DJ. Strategies to Counter Weight Loss-Induced Reductions in Metabolic Rate. Curr Sports Med Rep 2019; 18:258-265. [DOI: 10.1249/jsr.0000000000000610] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Phillips D, Bowman J, Zafren K. Successful Field Rewarming of a Patient with Apparent Moderate Hypothermia Using a Hypothermia Wrap and a Chemical Heat Blanket. Wilderness Environ Med 2019; 30:199-202. [PMID: 30824366 DOI: 10.1016/j.wem.2019.01.001] [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: 07/16/2018] [Revised: 12/02/2018] [Accepted: 01/04/2019] [Indexed: 11/18/2022]
Abstract
Hypothermia is a common problem encountered by search and rescue teams. Although mildly hypothermic patients can be rewarmed in the field and can then self-evacuate, the Wilderness Medical Society hypothermia guidelines suggest that a moderately hypothermic patient in the wilderness requires warming in a medical facility. The hypothermia prevention and management kit, developed by the US military, consists of a chemical heat blanket (CHB) and a heat-reflective shell. We present a case in which a hypothermia wrap and the CHB from a hypothermia prevention and management kit were used successfully to rewarm a patient with apparent moderate hypothermia in the field. We are unaware of previous reports of successful field rewarming of a patient with moderate hypothermia. We believe the use of the CHB in conjunction with a hypothermia wrap made field rewarming possible. We recommend that a CHB, along with the components of a hypothermia wrap, be carried by search and rescue teams when a hypothermic patient might be encountered. Although there were no documented core temperatures, we believe this case is consistent with the hypothesis that if a hypothermic patient who is found lying down and shivering is allowed to stand or walk before insulation is applied and before there has been an additional period of 30 min during which the patient continues to shiver, there may be increased afterdrop with deleterious results.
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Affiliation(s)
| | - Jason Bowman
- Lane County Sheriff's Office, Eugene, OR; Southern Arizona Rescue Association, Tucson, AZ
| | - Ken Zafren
- Department of Emergency Medicine, Alaska Native Medical Center, Anchorage, AK; Department of Emergency Medicine, Stanford University Medical Center, Stanford, CA; International Commission for Mountain Emergency Medicine (ICAR MEDCOM), Zürich, Switzerland.
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Clinical use of volumetric capnography in mechanically ventilated patients. J Clin Monit Comput 2019; 34:7-16. [PMID: 31152285 DOI: 10.1007/s10877-019-00325-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/21/2019] [Indexed: 10/26/2022]
Abstract
Capnography is a first line monitoring system in mechanically ventilated patients. Volumetric capnography supports noninvasive and breath-by-breath information at the bedside using mainstream CO2 and flow sensors placed at the airways opening. This volume-based capnography provides information of important body functions related to the kinetics of carbon dioxide. Volumetric capnography goes one step forward standard respiratory mechanics and provides a new dimension for monitoring of mechanical ventilation. The article discusses the role of volumetric capnography for the clinical monitoring of mechanical ventilation.
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Fujimoto T, Tsuji B, Sasaki Y, Dobashi K, Sengoku Y, Fujii N, Nishiyasu T. Low-intensity exercise delays the shivering response to core cooling. Am J Physiol Regul Integr Comp Physiol 2019; 316:R535-R542. [DOI: 10.1152/ajpregu.00203.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypothermia can occur during aquatic exercise despite production of significant amounts of heat by the active muscles. Because the characteristics of human thermoregulatory responses to cold during exercise have not been fully elucidated, we investigated the effect of low-intensity exercise on the shivering response to core cooling in cool water. Eight healthy young men (24 ± 3 yr) were cooled through cool water immersion while resting (rest trial) and during loadless pedaling on a water cycle ergometer (exercise trial). Before the cooling, body temperature was elevated by hot water immersion to clearly detect a core temperature at which shivering initiates. Throughout the cooling period, mean skin temperature remained around the water temperature (25°C) in both trials, whereas esophageal temperature (Tes) did not differ between the trials ( P > 0.05). The Tes at which oxygen uptake (V̇o2) rapidly increased, an index of the core temperature threshold for shivering, was lower during exercise than rest (36.2 ± 0.4°C vs. 36.5 ± 0.4°C, P < 0.05). The sensitivity of the shivering response, as indicated by the slope of the Tes-V̇o2 relation, did not differ between the trials (−441.3 ±177.4 ml·min−1·°C−1 vs. −411.8 ± 268.1 ml·min−1·°C−1, P > 0.05). The thermal sensation response to core cooling, assessed from the slope and intercept of the regression line relating Tes and thermal sensation, did not differ between the trials ( P > 0.05). These results suggest that the core temperature threshold for shivering is delayed during low-intensity exercise in cool water compared with rest although shivering sensitivity is unaffected.
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Affiliation(s)
- Tomomi Fujimoto
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Bun Tsuji
- Department of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Yosuke Sasaki
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
- Faculty of Economics, Niigata Sangyo University, Niigata, Japan
| | - Kohei Dobashi
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Yasuo Sengoku
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
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Kulkarni K, Hildahl E, Dutta R, Webber SC, Passmore S, McDonald GK, Giesbrecht GG. Efficacy of Head and Torso Rewarming Using a Human Model for Severe Hypothermia. Wilderness Environ Med 2019; 30:35-43. [DOI: 10.1016/j.wem.2018.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/30/2018] [Accepted: 11/08/2018] [Indexed: 12/25/2022]
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Xu X, Giesbrecht GG. A new look at survival times during cold water immersion. J Therm Biol 2018; 78:100-105. [PMID: 30509625 DOI: 10.1016/j.jtherbio.2018.08.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/30/2018] [Accepted: 08/27/2018] [Indexed: 11/18/2022]
Abstract
This paper presents an expanded dataset for survival times during cold water immersion. In 1946, the first set of human data for cold water survival was derived from the US Navy medical reports during WWII. Although this is the largest and most widely used data source, it has only 23 data points and immersion times are less than 5.5 h for water temperature below 20 °C. For the new dataset, data (i.e., immersion times, water temperatures, clothing worn, and in some cases, body masses, heights, and survival times for the deaths witnessed by survivors) was retrieved from 12 well-documented incidents of accidental immersions which involved 22 survivors and 21 deaths. These data were combined with the 1946 dataset to create the expanded dataset which included 122 data points. Analysis of the dataset revealed critical details pertinent to cold water survival: 1) immersion times, up to 75 h, at water temperatures below 20 °C, were longer than most immersion times documented in the 1946 dataset; 2) thermal protection (wetsuit or drysuit), high body mass, and partial immersion may significantly impact survival during immersion in cold water; 3) twenty-one actual survival times until witnessed death are added. A maximal survival time curve was derived to represent the survival limit which many victims are unlikely to approach and few can exceed except under unique circumstances.
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Affiliation(s)
- Xiaojiang Xu
- US Army Research Institute of Environmental Medicine, Biophysics and Biomedical Modeling Division, 10 General Greene Ave., Natick, MA 01760, United States.
| | - Gordon G Giesbrecht
- Laboratory for Exercise and Environmental Medicine, 108 Frank Kennedy, Faculty of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
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May TL, Riker RR, Gagnon DJ, Duarte C, McCrum B, Hoover C, Seder DB. Continuous surface EMG power reflects the metabolic cost of shivering during targeted temperature management after cardiac arrest. Resuscitation 2018; 131:8-13. [DOI: 10.1016/j.resuscitation.2018.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 07/16/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022]
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Kaikaew K, van den Beukel JC, Neggers SJCMM, Themmen APN, Visser JA, Grefhorst A. Sex difference in cold perception and shivering onset upon gradual cold exposure. J Therm Biol 2018; 77:137-144. [PMID: 30196892 DOI: 10.1016/j.jtherbio.2018.08.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 01/22/2023]
Abstract
To maintain a thermal balance when experiencing cold, humans reduce heat loss and enhance heat production. A potent and rapid mechanism for heat generation is shivering. Research has shown that women prefer a warmer environment and feel less comfortable than men in the same thermal condition. Using the Blanketrol® III, a temperature management device commonly used to study brown adipose tissue activity, we tested whether the experimental temperature (TE) at which men and women start to shiver differs. Twenty male and 23 female volunteers underwent a cooling protocol, starting at 24 °C and gradually decreasing by 1-2 °C every 5 min until an electromyogram detected the shivering or the temperature reached 9 °C. Women started shivering at a higher TE than men (11.3 ± 1.8 °C for women vs 9.6 ± 1.8 °C for men, P = 0.003). In addition, women felt cool, scored by a visual analogue scale, at a higher TE than men (18.3 ± 3.0 °C for women vs 14.6 ± 2.6 °C for men, P < 0.001). This study demonstrates a sex difference in response to cold exposure: women require shivering as a source of heat production earlier than men. This difference could be important and sex should be considered when using cooling protocols in physiological studies.
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Affiliation(s)
- Kasiphak Kaikaew
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Physiology, Faculty of Medicine, Chulalongkorn University, 1873, Rama IV Road, Pathumwan, Bangkok 10330, Thailand
| | - Johanna C van den Beukel
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Sebastian J C M M Neggers
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Axel P N Themmen
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands
| | - Jenny A Visser
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands.
| | - Aldo Grefhorst
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, the Netherlands
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Trans-Ferulic Acid-4-β-Glucoside Alleviates Cold-Induced Oxidative Stress and Promotes Cold Tolerance. Int J Mol Sci 2018; 19:ijms19082321. [PMID: 30096768 PMCID: PMC6121433 DOI: 10.3390/ijms19082321] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/30/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022] Open
Abstract
Trans-ferulic acid-4-β-glucoside (C16H20O9, TFA-4β-G) is a monomer extracted from the Chinese medicine called radix aconiti carmichaeli (Fuzi). To date, research on this substance is lacking. Here, we found that trans-ferulic acid-4-β-glucoside effectively promoted cold acclimatization in mice via increased heat production and alleviation of oxidative stress in a cold environment. Thus, our work indicates that ferulic acid-4-β-glucoside is a potential therapeutic candidate for prevention and treatment of cold stress injury.
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Hill M, Cahoon WD, Guanci MM, Blissitt PA, Hamilton LA. Clinical Q & A: Translating Therapeutic Temperature Management from Theory to Practice. Ther Hypothermia Temp Manag 2018; 8:121-124. [PMID: 29742037 DOI: 10.1089/ther.2018.29042.mkb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | | | | | | | - Leslie A Hamilton
- 6 University of Tennessee Health Science Center College of Pharmacy , Knoxville, Tennessee
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Acosta FM, Martinez-Tellez B, Sanchez-Delgado G, A. Alcantara JM, Acosta-Manzano P, Morales-Artacho AJ, R. Ruiz J. Physiological responses to acute cold exposure in young lean men. PLoS One 2018; 13:e0196543. [PMID: 29734360 PMCID: PMC5937792 DOI: 10.1371/journal.pone.0196543] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 04/14/2018] [Indexed: 01/21/2023] Open
Abstract
The aim of this study was to comprehensively describe the physiological responses to an acute bout of mild cold in young lean men (n = 11, age: 23 ± 2 years, body mass index: 23.1 ± 1.2 kg/m2) to better understand the underlying mechanisms of non-shivering thermogenesis and how it is regulated. Resting energy expenditure, substrate metabolism, skin temperature, thermal comfort perception, superficial muscle activity, hemodynamics of the forearm and abdominal regions, and heart rate variability were measured under warm conditions (22.7 ± 0.2°C) and during an individualized cooling protocol (air-conditioning and water cooling vest) in a cold room (19.4 ± 0.1°C). The temperature of the cooling vest started at 16.6°C and decreased ~ 1.4°C every 10 minutes until participants shivered (93.5 ± 26.3 min). All measurements were analysed across 4 periods: warm period, at 31% and at 64% of individual´s cold exposure time until shivering occurred, and at the shivering threshold. Energy expenditure increased from warm period to 31% of cold exposure by 16.7% (P = 0.078) and to the shivering threshold by 31.7% (P = 0.023). Fat oxidation increased by 72.6% from warm period to 31% of cold exposure (P = 0.004), whereas no changes occurred in carbohydrates oxidation. As shivering came closer, the skin temperature and thermal comfort perception decreased (all P<0.05), except in the supraclavicular skin temperature, which did not change (P>0.05). Furthermore, the superficial muscle activation increased at the shivering threshold. It is noteworthy that the largest physiological changes occurred during the first 30 minutes of cold exposure, when the participants felt less discomfort.
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Affiliation(s)
- Francisco M. Acosta
- PROFITH “PROmoting FITness and Health through physical activity” research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Borja Martinez-Tellez
- PROFITH “PROmoting FITness and Health through physical activity” research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Guillermo Sanchez-Delgado
- PROFITH “PROmoting FITness and Health through physical activity” research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Juan M. A. Alcantara
- PROFITH “PROmoting FITness and Health through physical activity” research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Pedro Acosta-Manzano
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Antonio J. Morales-Artacho
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Jonatan R. Ruiz
- PROFITH “PROmoting FITness and Health through physical activity” research group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
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Heinonen I, Laukkanen JA. Effects of heat and cold on health, with special reference to Finnish sauna bathing. Am J Physiol Regul Integr Comp Physiol 2018; 314:R629-R638. [DOI: 10.1152/ajpregu.00115.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Environmental stress such as extremely warm or cold temperature is often considered a challenge to human health and body homeostasis. However, the human body can adapt relatively well to heat and cold environments, and recent studies have also elucidated that particularly heat stress might be even highly beneficial for human health. Consequently, the aim of the present brief review is first to discuss general cardiovascular and other responses to acute heat stress, followed by a review of beneficial effects of Finnish sauna bathing on general and cardiovascular health and mortality as well as dementia and Alzheimer's disease risk. Plausible mechanisms included are improved endothelial and microvascular function, reduced blood pressure and arterial stiffness, and possibly increased angiogenesis in humans, which are likely to mediate the health benefits of sauna bathing. In addition to heat exposure with physiological adaptations, cold stress-induced physiological responses and brown fat activation on health are also discussed. This is important to take into consideration, as sauna bathing is frequently associated with cooling periods in cold(er) environments, but their combination remains poorly investigated. We finally propose, therefore, that possible additive effects of heat- and cold-stress-induced adaptations and effects on health would be worthy of further investigation.
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Affiliation(s)
- Ilkka Heinonen
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland
- Division of Experimental Cardiology, Thoraxcenter, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jari A. Laukkanen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
- Central Finland Health Care District, Jyväskylä, Finland
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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