Life Sciences Commons^™

The Effects Of Ultra-Marathon Trail Running And The Physiological Response Of Stress On Salivary Biomarkers, Kevan W. Stout, Jeremy R. Pearson, Catherine A. Hambleton, Jake A. Deckert, Philip M. Gallagher

Journal of Human Performance in Extreme Environments

PURPOSE: This study investigated changes in salivary α-amylase (sAA), cortisol, and interleukin-1β (IL-1β) concentrations following completion of an ultra-marathon trail run (UMT) to better understand the physiological stressors imposed by this extreme type of race. METHODS: Eight subjects participated in this study. Each subject completed a 50 km UMT. Two-minute oral salivary swabs were taken 10 minutes prior to race start and again within 1 minute of race finish. Samples were analyzed for sAA, cortisol and IL-1β using ELISA kits. RESULTS: Our results demonstrated a significant increase in both sAA (p = 0.002) and cortisol (p < 0.001) from baseline. No significant differences were observed for IL-1β. There was no significant relationship between the observed sAA increase and race speed. The observed increase in cortisol was significantly correlated with race speed (R² = 0.582, p …

Psychophysical Load During The Multistage Marathon Des Sables: A Case Study, Leonidas G. Ioannou, Lydia Tsoutsoubi, Georgios I. Tsianos, Andreas D. Flouris

Journal of Human Performance in Extreme Environments

Introduction: This study investigated the impact of the multistage ultra-marathon event ‘‘Marathon des Sables’’ (MdS) performed in the Sahara Desert on the psychophysical capacity of an athlete. Methods: We collected and analyzed environmental, physiological, and behavioral data from a 39-year-old athlete who participated in the MdS. Specifically, we collected environmental temperature (T_env), upper inguinal skin temperature (T_sk), heart rate, and running speed data. Also, we recorded blood glucose and lactate, thermal comfort, total body water, perceived exertion, and cognitive function at the start, middle, and the end of each race stage. Results: We found significant detrimental …

Influence Of Core Temperature On Psychomotor Performance During Cold Weather Military Training, Douglas Jones, Rebecca Weller, Stephen Eggan, Nicholas Roberts, Weimin Zheng, Jay Heaney, Timothy Dunn

Journal of Human Performance in Extreme Environments

Purpose: Cold environments may deteriorate psychomotor performance due to slowing of neuronal signals, distractions caused by pain and discomfort, and a loss of manual dexterity. The extent to which core temperature (T_c) influences psychomotor performance in the cold has not been established. Therefore, psychomotor performance and T_c were assessed during a cold weather military training exercise to evaluate this relationship.

Methods: Thirty-six military personnel (age: 26 ± 4 yr, ht: 175 ± 8 cm, wt: 79.1 ± 11.1 kg) participating in cold weather training volunteered for this study. Participants completed a 10-min immersion in cold (1°C) water, …

A Review Of The Effects Of Dietary Restriction, Dehydration, And Caffeine Withdrawal On Cognition: Implications For A Disabled Submarine Scenario, Sarah Chabal

Journal of Human Performance in Extreme Environments

In the event that submariners become trapped aboard a disabled submarine (DISSUB), they must perform a multitude of cognitively demanding tasks in order to maximize their likelihood of survival. During this time, submariners will also be forced to endure poor living conditions, including drastic changes to their nutrition. These nutritional changes have the potential to impair submariners’ cognitive functioning and affect operational performance, which could jeopardize survival; however, the effects of DISSUB nutrition on cognitive performance are not well understood. This review first describes the unique nutritional conditions that submariners will experience in a DISSUB scenario, including the change to …

Xp-Antarctik Expedition: The Effect Of A Month-Long Expedition In Antarctica On Physiological Performance, Andrée-Anne Parent, Daniel Martin, Sandra Morales, Jean Boucher, Alain-Steve Comtois

Journal of Human Performance in Extreme Environments

Antarctica is a challenging habitat for humans. A group of 6 explorers (3 women and 3 men) participated in an expedition in Antarctica. The objective was to observe the physiological acclimatization of the explorers using the following strategies: physical preparation, highcaloric nutritional intake, and the latest physiological monitoring and outdoor equipment. Anthropometric measures (dual x-ray absorptiometry), specific maximal aerobic test, maximal aerobic running speed test, submaximal aerobic cold testing, strength tests (grip strength, leg press and chin up), and endurance tests (bar suspension and chair position) were conducted pre- and post-expedition. Due to the sample size, a paired t-test was …

Thermoregulatory Adaptations Following Sprint Interval Training, Jonathan E. Wingo, Charlie P. Katica, Svetlana Nepocatych, Andrew T. Del Pozzi, Greg A. Ryan

Journal of Human Performance in Extreme Environments

Traditional endurance training typically involves weeks of long-duration (60–90 min) exercise performed at a moderate to vigorous intensity. An alternative paradigm, sprint interval training, is characterized by multiple bouts of short-duration, high-intensity exercise. Similar fitness benefits from the two paradigms have been demonstrated, but whether sprint interval training—like traditional endurance training—induces heat acclimation remains unclear.

Purpose

To test the hypothesis that sprint interval training performed over six sessions results in measureable thermoregulatory and cardiovascular adaptations consistent with heat acclimation.

Methods

Seven untrained men [mean ± SD, 13 ± 5% body fat, 22 ± 3 y, 3.1 ± 0.3 L/min peak …

Investigating Sociodemographic Disparities In Cancer Risk Using Web-Based Informatics, Hong-Jun Yoon, Georgia Tourassi

Journal of Human Performance in Extreme Environments

Cancer health disparities due to demographic and socioeconomic factors are an area of great interest in the epidemiological community. Adjusting for such factors is important when developing cancer risk models. However, for digital epidemiology studies relying on online sources such information is not readily available. This paper presents a novel method for extracting demographic and socioeconomic information from openly available online obituaries. The method relies on tailored language processing rules and a probabilistic scheme to map subjects’ occupation history to the occupation classification codes and related earnings provided by the U.S. Census Bureau. Using this information, a case-control study is …

Response Of Appetite And Appetite Regulating Hormones To Acute Hypoxia, Morgan Busboom, Robert Shute, Dustin Slivka

Journal of Human Performance in Extreme Environments

AIM: To determine the acute response of appetite and appetite regulating hormones after exposure to simulated altitude. METHODS: Seven males and five females (height: 178.9 ± 2.3 cm; weight: 77.3 ± 7.2 kg; body fat: 18.4 ± 1.7%) participated in two, three-hour trials in a hypoxic (5000 m) and normoxic (350 m) environment. Blood samples were collected prior to and immediately following three hours of exposure for the measurement of leptin, adiponectin, and acylated ghrelin. Appetite, acute mountain sickness, heart rate, blood oxygenation, tissue oxygenation, respiration rate, and whole body gases were also measured. RESULTS: Leptin was not different between …

Energy Balance During A Self-Sufficient, Multistage Ultramarathon, Paul A. Hough, James Earle

Journal of Human Performance in Extreme Environments

Endurance athletes are recommended to maintain energy balance and ensure adequate energy availability (EA) so that endurance performance is not compromised. Purpose: Describe and evaluate the energy balance of an athlete competing in a self-sufficient, multistage ultramarathon (MSU). Methods: A male endurance athlete (age 35 years; height 183.0 cm; body mass 78.4 kg; VO_2max 66 ml/kg/min) volunteered to take part in this observational case study prior to competing in the Marathon des Sables (MdS) 2016. The subject self-reported energy intake (EI) by reviewing his dietary plan following each stage. Basal metabolic rate (BMR) was estimated prior to the MdS …

Exercise-Induced Interleukin-6 And Metabolic Responses In Hot, Temperate, And Cold Conditions, Nicholas E. Dinan, Roksana B. Zak, Robert J. Shute, Terry Laursen, Matthew Bubak, D. Taylor La Salle, Matthew W.S. Heesch, Dustin R. Slivka

Journal of Human Performance in Extreme Environments

The purpose of this study was to determine the effects of exercise in hot, cold, and temperate environments on plasma interleukin-6 (IL-6). Eleven recreationally trained males (age = 25 ± 4 years, height = 178 ± 5 cm, weight = 79.4 ± 13.5 kg, body fat = 14.7 ± 3.6%, VO₂ peak = 54.6 ± 11.5 ml kg^-1 min^-1) performed a 1 hr cycling bout in hot (33 °C), cold (7 °C), and temperate (20 °C) environments at 60% of W_max followed by 3 hr of supine recovery in temperate conditions. Expired gases were measured …

Effects Of Pre-Acclimatization Applying The ‘‘Climb High And Sleep Low’’ Maxim: An Example Of Rapid But Safe Ascent To Extreme Altitude, Martin Burtscher, Robert Koch

Journal of Human Performance in Extreme Environments

Pre-acclimatization at a convenient high-altitude location may represent an appropriate method before climbing a more hostile target mountain. The aim of the present field report was to demonstrate the effectiveness of such pre-acclimatizing applying the ‘‘climb high sleep low’’ maxim for a subsequent rapid ascent to almost 7000 m. After some pre-acclimatization in the Alps the authors flew to Chile for further pre-acclimatization in the Aymara village of Putre (3650 m). From there they undertook sojourns up to altitudes of 5700 m within 3 days. Subsequently they went back to Arica (sea level) and climbed Ojos del Salado (6893 m) …

Changes In Intragastric Temperature Reflect Changes In Heat Stress Following Tepid Fluid Ingestion But Not Ice Slurry Ingestion, Christopher J. Stevens, Ben Dascombe

Journal of Human Performance in Extreme Environments

This study examined the effects of fluid and ice slurry ingestion on the relationship between intragastric temperature and rectal temperature in humans during physical activity. The purpose was to identify a technique to quantify changes in heat stress in situations when temperature probes are not feasible and when time constraints do not allow for a period long enough for an indigestible temperature capsule to reach the lower gastrointestinal tract. Eight moderately trained male runners inserted a rectal probe and ingested a telemetric capsule before randomized, crossover, pre-exercise ingestion of 7.5 mL x kg^-1 x BM^-1tepid fluid (22°C) …