Physiology 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 …

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 …

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 …

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) …