Antarctic Expeditions: A Systematic Review of the Physiological, Nutritional, Body Composition and Psychological Responses to Treks Across the Continental Ice.

Background: Antarctic expeditions, although supported by scientific knowledge, face various challenges, with little research conducted to explore the physical demands that explorers experience.

Objective: To summarise physiological, psychological, body composition and nutritional changes faced during trek expeditions in the Antarctic's continental portion.

Design: Systematic review.

The relevance of body composition assessment for the rating of perceived exertion in trained and untrained women and men.

Mechanic power output (MPO) and oxygen consumption (VO) reflect endurance capacity and are often stated relative to body mass (BM) but less often per skeletal muscle mass (SMM). Rating of perceived exertion (RPE) has previously shown conflicting results between sexes at submaximal intensities. Individual body composition, however, largely differs due to sex and training status.

Adiponectin, leptin, cortisol, neuropeptide Y and profile of mood states in athletes participating in an ultramarathon during winter: An observational study.

The Montane Yukon Arctic Ultra (YAU) is one of the longest (690 km) and coldest (+10.6°C-43.9°C) ultramarathons worldwide.

Influences on glycocalyx shedding during the Yukon Arctic Ultra: the longest and the coldest ultramarathon.

The endothelial glycocalyx maintains vascular structure and may be subject to shedding during inflammation and also during high-intensive exercise. There are no studies on shedding during ultra-endurance exercise. The "Yukon Arctic Ultra" (YAU) is one of the longest and coldest ultramarathons and its impact on glycocalyx shedding was investigated.

The Association of Fatigue With Decreasing Regularity of Locomotion During an Incremental Test in Trained and Untrained Healthy Adults.

Fatigue is a key factor that affects human motion and modulates physiology, biochemistry, and performance. Prolonged cyclic human movements (locomotion primarily) are characterized by a regular pattern, and this extended activity can induce fatigue. However, the relationship between fatigue and regularity has not yet been extensively studied.

Long-Term Bed Rest Delays the Circadian Phase of Core Body Temperature.

Spaceflight can be associated with sleep loss and circadian misalignment as a result of non-24 h light-dark cycles, operational shifts in work/rest cycles, high workload under pressure, and psychological factors. Head-down tilt bed rest (HDBR) is an established model to mimic some of the physiological and psychological adaptions observed in spaceflight. Data on the effects of HDBR on circadian rhythms are scarce.

Physiological Changes, Activity, and Stress During a 100-km-24-h Walking-March.

Background: Long-endurance exercises like ultramarathons are known to elicit various metabolic and physiological changes in the human body. However, little is known about very long-duration exercise at low intensities regarding healthy human subjects.

Aim: The purpose of this study was to evaluate changes in body composition and metabolism in long-endurance but low-intensity events.

Regular exercise counteracts circadian shifts in core body temperature during long-duration bed rest.

With NASA's plans for the human exploration of Mars, astronauts will be exposed to mission durations much longer than current spaceflight missions on the International Space Station. These mission durations will increase the risk for circadian misalignment. Exercise has gained increasing interest as a non-pharmacological aid to entrain the circadian system.

A broad diversity in oxygen affinity to haemoglobin.

Oxygen affinity to haemoglobin is indicated by the p50 value (pO at 50% OHb) and critically determines cellular oxygen availability. Although high Hb-O affinity can cause tissue hypoxia under conditions of well O saturated blood, individual differences in p50 are commonly not considered in clinical routine. Here, we investigated the diversity in Hb-O affinity in the context of physiological relevance.

The Advantage of Supine and Standing Heart Rate Variability Analysis to Assess Training Status and Performance in a Walking Ultramarathon.

Cardiac autonomic modulation of heart rate, assessed by heart rate variability (HRV), is commonly used to monitor training status. HRV is usually measured in athletes after awakening in the morning in the supine position. Whether recording during standing reveals additional information compared to supine remains unclear.

Negative Energy Balance Does Not Alter Fat-Free Mass During the Yukon Arctic Ultra-The Longest and the Coldest Ultramarathon.

The objective of this study was to determine alterations in caloric balance, body composition, metabolites, and cytokines in athletes participating in the Yukon Arctic Ultra. Ten participants traveling on foot in the 2017 692-km event were recruited for the study. Measurements and samples were obtained at pre-event, 278 km (C1), 384 km (C2), and post-event.

High-Intensity Exercise Mitigates Cardiovascular Deconditioning During Long-Duration Bed Rest.

Head-down-tilt bed rest (HDT) mimics the changes in hemodynamics and autonomic cardiovascular control induced by weightlessness. However, the time course and reciprocal interplay of these adaptations, and the effective exercise protocol as a countermeasure need further clarification. The overarching aim of this work (as part of a European Space Agency sponsored long-term bed rest study) was therefore to evaluate the time course of cardiovascular hemodynamics and autonomic control during prolonged HDT and to assess whether high-intensity, short-duration exercise could mitigate these effects.

Limb Skin Temperature as a Tool to Predict Orthostatic Instability.

Orthostatic instability is one of the main consequences of weightlessness or gravity challenge and plays as well a crucial role in public health, being one of the most frequent disease of aging. Therefore, the assessment of effective countermeasures, or even the possibility to predict, and thus prevent orthostatic instability is of great importance. Heat stress affects orthostatic stability and may lead to impaired consciousness and decrease in cerebral perfusion, specifically during the exposure to G-forces.

Cardiac Autonomic Modulations and Psychological Correlates in the Yukon Arctic Ultra: The Longest and the Coldest Ultramarathon.

Studies on human physical performance in extreme environments have effectively approached the investigation of adaptation mechanisms and their physiological limits. As scientific interest in the interplay between physiological and psychological aspects of performance is growing, we aimed to investigate cardiac autonomic control, by means of heart rate variability, and psychological correlates, in competitors of a subarctic ultramarathon, taking place over a 690 km course (temperatures between +5 and -47°C). At baseline (PRE), after 277 km (D1), 383 km (D2), and post-race (POST, 690 km), heart rate (HR) recordings (supine, 15 min), psychometric measurements (Profile of Mood States/POMS, Borg fatigue, and Karolinska Sleepiness Scale scores both upon arrival and departure) were obtained in 16 competitors (12 men, 4 women, 38.

Increased core body temperature in astronauts during long-duration space missions.

Humans' core body temperature (CBT) is strictly controlled within a narrow range. Various studies dealt with the impact of physical activity, clothing, and environmental factors on CBT regulation under terrestrial conditions. However, the effects of weightlessness on human thermoregulation are not well understood.

Circadian rhythms in bed rest: Monitoring core body temperature via heat-flux approach is superior to skin surface temperature.

Continuous recordings of core body temperature (CBT) are a well-established approach in describing circadian rhythms. Given the discomfort of invasive CBT measurement techniques, the use of skin temperature recordings has been proposed as a surrogate. More recently, we proposed a heat-flux approach (the so-called Double Sensor) for monitoring CBT.

Metabolic Responses to the Yukon Arctic Ultra: Longest and Coldest in the World.

Purpose: The Yukon Arctic Ultra is considered the longest and coldest ultraendurance event in the world. Cold exposure and exercise has been reported to influence circulating levels of myokines, adipokines, and hepatokines that may influence considerable alterations in the regulation of metabolism. The purpose of the study was to evaluate the influence of the Yukon Arctic Ultra (430-mile event) on potential activators of brown fat, metabolites, and body composition in healthy individuals.

Sleep Quality Changes during Overwintering at the German Antarctic Stations Neumayer II and III: The Gender Factor.

Purpose: Antarctic residence holds many challenges to human physiology, like increased psycho-social tension and altered circadian rhythm, known to influence sleep. We assessed changes in sleep patterns during 13 months of overwintering at the German Stations Neumayer II and III from 2008 to 2014, with focus on gender, as many previous investigations were inconclusive regarding gender-based differences or had only included men.

Materials & Methods: Time in bed, sleep time, sleep efficiency, number of arousals, sleep latency, sleep onset, sleep offset, and physical activity level were determined twice per month during seven overwintering campaigns of n = 54 participants (37 male, 17 female) using actimetry.

Changes of 25-OH-Vitamin D during Overwintering at the German Antarctic Stations Neumayer II and III.

Purpose: Humans in Antarctica face different environmental challenges, such as low ultra-violet radiation, which is crucial for vitamin D production in humans. Therefore we assessed changes in 25-OH-vitamin D serum concentration during 13 months of overwintering at the German Stations Neumayer II and III (2007-2012). We hypothesized that (i) 25-OH-vitamin D serum concentration would significantly decrease, (ii) changes would be affected by age, gender, baseline (i.

Changes in the haemostatic system after thermoneutral and hyperthermic water immersion.

Warm water bathing is a popular recreational activity and is frequently used in rehabilitation medicine. Although well tolerated in most cases, there are reports indicating an increased risk of thrombotic events after hot tub bathing. The effects of a 45 min thermoneutral bath followed by a 50 min bath with increasing water temperature (maximum 41 degrees C) until reaching a body core temperature of 39 degrees C on factors of blood coagulation and fibrinolysis were studied in eight healthy male volunteers.