Extreme physiology & medicine最新文献

{"title":"Career perspective: Kenneth J. Collins.","authors":"Kenneth John Collins","doi":"10.1186/s13728-017-0058-4","DOIUrl":"https://doi.org/10.1186/s13728-017-0058-4","url":null,"abstract":"<p><p>A career interest in thermoregulation research has included wide contrasts in the subjects of enquiry, extending from heat stroke to hypothermia, special investigations in many different purpose-built climatic chambers, laboratory-based biomedical studies together with hospital practice, and field work in tropical climates to physiological surveys on urban populations in temperate environments. The scientific process and need to focus on careful planning of experiments, using the most appropriate methods, selecting the right controls and eventually applying correct statistical analysis do not always follow a smooth transition, as illustrated in this account. The result of endeavour to resolve a human environmental problem, however, is greatly satisfying, and sometimes becomes a unique experience when the solution reveals new fundamental facts.</p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"7 ","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2018-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13728-017-0058-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35801974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transient cardiac dysfunction but elevated cardiac and kidney biomarkers 24 h following an ultra-distance running event in Mexican Tarahumara.","authors":"Dirk L Christensen,&nbsp;Diana Espino,&nbsp;Rocío Infante-Ramírez,&nbsp;Mónica S Cervantes-Borunda,&nbsp;Rosa P Hernández-Torres,&nbsp;Antonio E Rivera-Cisneros,&nbsp;Daniel Castillo,&nbsp;Kate Westgate,&nbsp;Dijana Terzic,&nbsp;Soren Brage,&nbsp;Christian Hassager,&nbsp;Jens P Goetze,&nbsp;Jesper Kjaergaard","doi":"10.1186/s13728-017-0057-5","DOIUrl":"https://doi.org/10.1186/s13728-017-0057-5","url":null,"abstract":"<p><strong>Background: </strong>The Mexican Tarahumara are accustomed to running ultra-distance races. No data exist on the acute physiological changes following ultra-distance running and physiological-biomarker associations in this population. Thus, we aimed to investigate the acute impact (≤ 24 h) on functional and biochemical changes of the cardiac muscle and biochemical changes associated with kidney function following a 63-km ultra-distance race with an altitude difference of 1800 m in Mexican Tarahumara athletes.</p><p><strong>Methods: </strong>Ten Tarahumara male athletes (mean ± SD age = 29.9 ± 6.6 years) volunteered to participate in the study. VO₂max was assessed by a sub-maximal step test individually calibrated combining heart rate and accelerometry. Standard transthoracic echocardiography methodology and venipuncture blood tests were carried out at four time points: pre-race, immediately post-race, 6 h, and 24 h post-race.</p><p><strong>Results: </strong>Estimated mean VO₂max was 54.5 (± 8.8) mL O₂ min^-1 kg^-1 and average physiological activity intensity was 746 (± 143) J min^-1 kg ^-1 (~ 11.5 METs). When compared to pre-race values, significant changes in left ventricular ejection fraction (LVEF) and LV end-diastolic volume (- 15%, <i>p</i> < 0.001 for both parameters), cardiac output (39%, <i>p</i> < 0.001), and maximal longitudinal velocity (- 13%, <i>p</i> < 0.009) were seen post-race with LVEF also being decreased at < 6 h post-race (- 8%, <i>p</i> < 0.014). Plasma biomarkers mid-regional pro-atrial natriuretic peptide, copeptin-ultra sensitive, and high-sensitivity cardiac troponin T remained significantly elevated at 24 h post-race, and the two latter were inversely associated with LVEF (<i>p</i> < 0.04). Kidney dysfunction was indicated by increased post-race copeptin-ultra sensitive.</p><p><strong>Conclusions: </strong>The athletes participating in this study had acute transient cardiac dysfunction as assessed by echocardiography but elevated cardiac and kidney biomarkers at 24 h following a 63-km race with extreme altitude variation.</p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"6 ","pages":"3"},"PeriodicalIF":0.0,"publicationDate":"2017-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13728-017-0057-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35654621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cardiovascular and thermal strain during 3-4 days of a metabolically demanding cold-weather military operation.","authors":"John W Castellani,&nbsp;Marissa G Spitz,&nbsp;Anthony J Karis,&nbsp;Svein Martini,&nbsp;Andrew J Young,&nbsp;Lee M Margolis,&nbsp;J Phillip Karl,&nbsp;Nancy E Murphy,&nbsp;Xiaojiang Xu,&nbsp;Scott J Montain,&nbsp;Jamie A Bohn,&nbsp;Hilde K Teien,&nbsp;Pål H Stenberg,&nbsp;Yngvar Gundersen,&nbsp;Stefan M Pasiakos","doi":"10.1186/s13728-017-0056-6","DOIUrl":"https://doi.org/10.1186/s13728-017-0056-6","url":null,"abstract":"<p><strong>Background: </strong>Cardiovascular (CV) and thermal responses to metabolically demanding multi-day military operations in extreme cold-weather environments are not well described. Characterization of these operations will provide greater insights into possible performance capabilities and cold injury risk.</p><p><strong>Methods: </strong>Soldiers from two cold-weather field training exercises (FTX) were studied during 3-day (study 1, <i>n</i> = 18, age: 20 ± 1 year, height: 182 ± 7 cm, mass: 82 ± 9 kg) and 4-day (study 2, <i>n</i> = 10, age: 20 ± 1 year, height: 182 ± 6 cm, mass: 80.7 ± 8.3 kg) ski marches in the Arctic. Ambient temperature ranged from -18 to -4 °C during both studies. Total daily energy expenditure (TDEE, from doubly labeled water), heart rate (HR), deep body (<i>T</i>_pill), and torso (<i>T</i>_torso) skin temperature (obtained in studies 1 and 2) as well as finger (<i>T</i>_fing), toe (<i>T</i>_toe), wrist, and calf temperatures (study 2) were measured.</p><p><strong>Results: </strong>TDEE was 6821 ± 578 kcal day^-1 and 6394 ± 544 for study 1 and study 2, respectively. Mean HR ranged from 120 to 140 bpm and mean <i>T</i>_pill ranged between 37.5 and 38.0 °C during skiing in both studies. At rest, mean <i>T</i>_pill ranged from 36.0 to 36.5 °C, (lowest value recorded was 35.5 °C). Mean <i>T</i>_fing ranged from 32 to 35 °C during exercise and dropped to 15 °C during rest, with some <i>T</i>_fing values as low as 6-10 °C. T_toe was above 30 °C during skiing but dropped to 15-20 °C during rest.</p><p><strong>Conclusions: </strong>Daily energy expenditures were among the highest observed for a military training exercise, with moderate exercise intensity levels (~65% age-predicted maximal HR) observed. The short-term cold-weather training did not elicit high CV and <i>T</i>_pill strain. <i>T</i>_fing and <i>T</i>_toe were also well maintained while skiing, but decreased to values associated with thermal discomfort at rest.</p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"6 ","pages":"2"},"PeriodicalIF":0.0,"publicationDate":"2017-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13728-017-0056-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35382762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements of rates of cooling of a manikin insulated with different mountain rescue casualty bags.","authors":"Christopher Press,&nbsp;Christopher Duffy,&nbsp;Jonathan Williams,&nbsp;Ben Cooper,&nbsp;Neil Chapman","doi":"10.1186/s13728-017-0055-7","DOIUrl":"https://doi.org/10.1186/s13728-017-0055-7","url":null,"abstract":"<p><strong>Background: </strong>Accidental hypothermia is common in those who sustain injuries in remote environments. This is unpleasant and associated with adverse effects on subsequent patient outcomes. To minimise further heat loss, a range of insulating systems are available to mountain rescue teams although the most effective and cost-efficient have yet to be determined.</p><p><strong>Methods: </strong>Under ambient, still, dry, air conditions, a thermal manikin was filled with water at a temperature of 42 °C and then placed into a given insulation system. Water temperature was then continuously observed via an in-dwelling temperature sensor linked to a PROPAQ 100 series monitor and recorded every 10 min for 130 min. This method was repeated for each insulating package.</p><p><strong>Results: </strong>The vacuum mattress/Pertex©/fibrepile blanket system, either on its own or coupled with the Wiggy bag, was the most efficient with water temperatures only decreasing by 3.2 °C over 130 min. This was followed by the heavy-weight casualty bags without the vacuum mattress/Pertex©/fibrepile blanket system, decreasing by 4.2-4.3 °C. With the Blizzard bag, a decline in water temperature of 5.4 °C was seen over the study duration while a decrease of 9.5 °C was noted when the plastic survival bag was employed.</p><p><strong>Conclusions: </strong>Under the still-air conditions of the study, the vacuum mattress/Pertex©/fibrepile blanket was seen to offer comparable insulation effectiveness compared to be both heavy-weight casualty bags. In turn, these three systems appeared more efficient at insulating the manikin than the Blizzard bag or plastic survival bag.</p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"6 ","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2017-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13728-017-0055-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35015740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In conversation with…Thomas Frederic Hornbein","authors":"N. Gilbert-Kawai","doi":"10.1186/s13728-016-0053-1","DOIUrl":"https://doi.org/10.1186/s13728-016-0053-1","url":null,"abstract":"","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77931293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Keratinocytes at the uppermost layer of epidermis might act as sensors of atmospheric pressure change","authors":"M. Denda","doi":"10.1186/s13728-016-0052-2","DOIUrl":"https://doi.org/10.1186/s13728-016-0052-2","url":null,"abstract":"","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75870455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High altitude-related hypertensive crisis and acute kidney injury in an asymptomatic healthy individual","authors":"E. Gilbert-kawai, D. Martin, M. Grocott, D. Levett","doi":"10.1186/s13728-016-0051-3","DOIUrl":"https://doi.org/10.1186/s13728-016-0051-3","url":null,"abstract":"","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90701988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exercise in space: the European Space Agency approach to in-flight exercise countermeasures for long-duration missions on ISS.","authors":"Nora Petersen,&nbsp;Patrick Jaekel,&nbsp;Andre Rosenberger,&nbsp;Tobias Weber,&nbsp;Jonathan Scott,&nbsp;Filippo Castrucci,&nbsp;Gunda Lambrecht,&nbsp;Lori Ploutz-Snyder,&nbsp;Volker Damann,&nbsp;Inessa Kozlovskaya,&nbsp;Joachim Mester","doi":"10.1186/s13728-016-0050-4","DOIUrl":"https://doi.org/10.1186/s13728-016-0050-4","url":null,"abstract":"<p><strong>Background: </strong>To counteract microgravity (µG)-induced adaptation, European Space Agency (ESA) astronauts on long-duration missions (LDMs) to the International Space Station (ISS) perform a daily physical exercise countermeasure program. Since the first ESA crewmember completed an LDM in 2006, the ESA countermeasure program has strived to provide efficient protection against decreases in body mass, muscle strength, bone mass, and aerobic capacity within the operational constraints of the ISS environment and the changing availability of on-board exercise devices. The purpose of this paper is to provide a description of ESA's individualised approach to in-flight exercise countermeasures and an up-to-date picture of how exercise is used to counteract physiological changes resulting from µG-induced adaptation. Changes in the absolute workload for resistive exercise, treadmill running and cycle ergometry throughout ESA's eight LDMs are also presented, and aspects of pre-flight physical preparation and post-flight reconditioning outlined.</p><p><strong>Results: </strong>With the introduction of the advanced resistive exercise device (ARED) in 2009, the relative contribution of resistance exercise to total in-flight exercise increased (33-46 %), whilst treadmill running (42-33 %) and cycle ergometry (26-20 %) decreased. All eight ESA crewmembers increased their in-flight absolute workload during their LDMs for resistance exercise and treadmill running (running speed and vertical loading through the harness), while cycle ergometer workload was unchanged across missions.</p><p><strong>Conclusion: </strong>Increased or unchanged absolute exercise workloads in-flight would appear contradictory to typical post-flight reductions in muscle mass and strength, and cardiovascular capacity following LDMs. However, increased absolute in-flight workloads are not directly linked to changes in exercise capacity as they likely also reflect the planned, conservative loading early in the mission to allow adaption to µG exercise, including personal comfort issues with novel exercise hardware (e.g. the treadmill harness). Inconsistency in hardware and individualised support concepts across time limit the comparability of results from different crewmembers, and questions regarding the difference between cycling and running in µG versus identical exercise here on Earth, and other factors that might influence in-flight exercise performance, still require further investigation.</p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"5 ","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2016-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13728-016-0050-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34731186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chronic occupational exposures can influence the rate of PTSD and depressive disorders in first responders and military personnel.","authors":"Anthony Walker, Andrew McKune, Sally Ferguson, David B Pyne, Ben Rattray","doi":"10.1186/s13728-016-0049-x","DOIUrl":"10.1186/s13728-016-0049-x","url":null,"abstract":"<p><strong>Background: </strong>First responders and military personnel experience rates of post-traumatic stress disorder (PTSD) far in excess of the general population. Although exposure to acute traumatic events plays a role in the genesis of these disorders, in this review, we present an argument that the occupational and environmental conditions where these workers operate are also likely contributors.</p><p><strong>Presentation of the hypothesis: </strong>First responders and military personnel face occupational exposures that have been associated with altered immune and inflammatory activity. In turn, these physiological responses are linked to altered moods and feelings of well-being which may provide priming conditions that compromise individual resilience, and increase the risk of PTSD and depression when subsequently exposed to acute traumatic events. These exposures include heat, smoke, and sleep restriction, and physical injury often alongside heavy physical exertion. Provided the stimulus is sufficient, these exposures have been linked to inflammatory activity and modification of the hypothalamic-pituitary axis (HPA), offering a mechanism for the high rates of PTSD and depressive disorders in these occupations.</p><p><strong>Testing the hypothesis: </strong>To test this hypothesis in the future, a case-control approach is suggested that compares individuals with PTSD or depressive disorders with healthy colleagues in a retrospective framework. This approach should characterise the relationships between altered immune and inflammatory activity and health outcomes. Wearable technology, surveys, and formal experimentation in the field will add useful data to these investigations.</p><p><strong>Implications of the hypothesis: </strong>Inflammatory changes, linked with occupational exposures in first responders and military personnel, would highlight the need for a risk management approach to work places. Risk management strategies could focus on reducing exposure, ensuring recovery, and increasing resilience to these risk contributors to minimise the rates of PTSD and depressive disorders in vulnerable occupations.</p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"5 ","pages":"8"},"PeriodicalIF":0.0,"publicationDate":"2016-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947320/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34581069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Psychological factors in exceptional, extreme and torturous environments.","authors":"John Leach","doi":"10.1186/s13728-016-0048-y","DOIUrl":"https://doi.org/10.1186/s13728-016-0048-y","url":null,"abstract":"<p><p>Our cognitive system has adapted to support goal-directed behaviour within a normal environment. An abnormal environment is one to which we are not optimally adapted but can accommodate through the development of coping strategies. These abnormal environments can be 'exceptional', e.g., polar base, space station, submarine, prison, intensive care unit, isolation ward etc.; 'extreme', marked by more intense environmental stimuli and a real or perceived lack of control over the situation, e.g., surviving at sea in a life-raft, harsh prison camp etc.; or 'tortuous', when specific environmental stimuli are used deliberately against a person in an attempt to undermine his will or resistance. The main factors in an abnormal environment are: psychological (isolation, sensory deprivation, sensory overload, sleep deprivation, temporal disorientation); psychophysiological (thermal, stress positions), and psychosocial (cultural humiliation, sexual degradation). Each single factor may not be considered tortuous, however, if deliberately structured into a systemic cluster may constitute torture under legal definition. The individual experience of extremis can be pathogenic or salutogenic and attempts are being made to capitalise on these positive experiences whilst ameliorating the more negative aspects of living in an abnormal environment. </p>","PeriodicalId":89765,"journal":{"name":"Extreme physiology & medicine","volume":"5 ","pages":"7"},"PeriodicalIF":0.0,"publicationDate":"2016-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s13728-016-0048-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34446507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}