The repeatability of a cycling exercise-heat stress test in a male population.

Introduction: There is considerable inter-individual variability in the physiological responses to environmental stressors and so to accurately assess and monitor changes in an individual's ability to cope with exercise-heat stress, a reliable protocol is required. The aim of this study was to examine the repeatability of a 90-min steady-state heat exercise bout with physiological and subjective variables, and performance during an incremental test to exhaustion post 90-min steady-state exercise.

Method: Sixteen mixed ability males (Age: 39 ± 15yrs; Height: 176.

IL-21 conditions antigen-presenting human γδ T-cells to promote IL-10 expression in naïve and memory CD4 T-cells.

Direct interaction between T-cells exerts a major influence on tissue immunity and inflammation across multiple body sites including the human gut, which is highly enriched in 'unconventional' lymphocytes such as γδ T-cells. We previously reported that microbial activation of human Vγ9/Vδ2 γδ T-cells in the presence of the mucosal damage-associated cytokine IL-15 confers the ability to promote epithelial barrier defence, specifically via induction of IL-22 expression in conventional CD4 T-cells. In the current report, we assessed whether other cytokines enriched in the gut milieu also functionally influence microbe-responsive Vγ9/Vδ2 T-cells.

Myths and methodologies: Considerations for evaluating the time course of thermoregulatory adaptation during heat acclimation.

Since the early 1900s, repeated heat exposure has been used as a method to induce physiological adaptations that enhance our ability to tolerate heat stress during athletic and occupational pursuits. Much of this work has been dedicated to quantifying the time course of adaptation and identifying the minimum duration of acclimation required to optimise performance or enhance safety. To achieve this, investigators have typically applied classical (constant load) heat acclimation, whereby 60-90 min exercise is performed at the same absolute or relative intensity in a hot environment for 3-24 days, with adaptations evaluated using an identical forcing function test before and after.

Voluntary torque production is unaffected by changes in local thermal sensation during normothermia and hyperthermia.

New Findings: What is the central question of this study? Hyperthermia reduces the human capacity to produce muscular force, which is associated with decreased neural drive: does mitigating a reduction in neural drive by altering localised thermal sensation help to preserve voluntary force output? What is the main finding and its importance? Altering thermal sensation by cooling and heating the head independent of core temperature did not change neural drive or benefit voluntary force production. Head cooling did slow the rate of rise in core temperature during heating, which may have practical applications in passive settings.

Abstract: This study investigated altered local head and neck thermal sensation on maximal and rapid torque production during voluntary contractions.

Heat acclimation reduces the effects of whole-body hyperthermia on knee-extensor relaxation rate, but does not affect voluntary torque production.

Purpose: This study investigated the effects of acute hyperthermia and heat acclimation (HA) on maximal and rapid voluntary torque production, and their neuromuscular determinants.

Methods: Ten participants completed 10 days of isothermic HA (50 °C, 50% rh) and had their knee-extensor neuromuscular function assessed in normothermic and hyperthermic conditions, pre-, after 5 and after 10 days of HA. Electrically evoked twitch and octet (300 Hz) contractions were delivered at rest.

The effects of combined action observation and motor imagery on corticospinal excitability and movement outcomes: Two meta-analyses.

Motor simulation interventions involving motor imagery (MI) and action observation (AO) have received considerable interest in the behavioral sciences. A growing body of research has focused on using AO and MI simultaneously, termed 'combined action observation and motor imagery' (AOMI). The current paper includes two meta-analyses that quantify changes in corticospinal excitability and motor skill performance for AOMI compared to AO, MI and control conditions.

Correction: Cold-Induced Vasodilation during Single Digit Immersion in 0°C and 8°C Water in Men and Women.

[This corrects the article DOI: 10.1371/journal.pone.

The Influence of a Competitive Field Hockey Match on Cognitive Function.

Despite the known positive effects of acute exercise on cognition, the effects of a competitive team sport match are unknown. In a randomized crossover design, 20 female and 17 male field hockey players (19.7 ± 1.

Antibody secreting cells are critically dependent on integrin α4β7/MAdCAM-1 for intestinal recruitment and control of the microbiota during chronic colitis.

T and B cells employ integrin α4β7 to migrate to intestine under homeostatic conditions. Whether those cells differentially rely on α4β7 for homing during inflammatory conditions has not been fully examined. This may have implications for our understanding of the mode of action of anti-integrin therapies in inflammatory bowel disease (IBD).

An integrin αEβ7-dependent mechanism of IgA transcytosis requires direct plasma cell contact with intestinal epithelium.

Efficient IgA transcytosis is critical for the maintenance of a homeostatic microbiota. In the canonical model, locally-secreted dimeric (d)IgA reaches the polymeric immunoglobulin receptor (pIgR) on intestinal epithelium via simple diffusion. A role for integrin αE(CD103)β7 during transcytosis has not been described, nor its expression by intestinal B cell lineage cells.

Keeping environmental physiology education up and running during the COVID-19 pandemic.

The COVID-19 pandemic provoked a need for rapid adaptation of teaching strategies and learning environments. Thus novel approaches, predominantly based on online/virtual platforms are needed to minimize the negative effects of the pandemic on teaching (and learning). Herein we describe our recent web-based symposium series on environmental physiology and ergonomics initiative as an example of such a strategy.

The effects of pre- and per-cooling interventions used in isolation and combination on subsequent 15-minute time-trial cycling performance in the heat.

Objectives: To investigate the effects of pre- and per-cooling interventions on subsequent 15-min time-trial (TT) cycling performance in the heat.

Design: Randomized cross-over design.

Methods: Nine male athletes completed four experimental trials in the heat (40 °C, 50% rh): no-cooling (CON); warm-up per-cooling (PER: neck-cooling collar applied during the preload); pre-cooling (PRE: 30 min of cold water (22 °C) immersion [CWI]); and pre- and per-cooling combined (PRE + PER).

Progressive hyperthermia elicits distinct responses in maximum and rapid torque production.

Objectives: To investigate the effect of progressive whole-body hyperthermia on maximal, and rapid voluntary torque production, and their neuromuscular determinants.

Design: Repeated measures, randomised.

Methods: Nine participants performed sets of neuromuscular assessments in HOT conditions (∼50°C, ∼35% relative humidity) at rectal temperatures (T) of 37, 38.

The effect of head and neck per-cooling on neuromuscular fatigue following exercise in the heat.

The effect of localised head and neck per-cooling on central and peripheral fatigue during high thermal strain was investigated. Fourteen participants cycled for 60 min at 50% peak oxygen uptake on 3 occasions: thermoneutral control (CON; 18 °C), hot (HOT; 35 °C), and HOT with head and neck cooling (HOT). Maximal voluntary force (MVF) and central activation ratio (CAR) of the knee extensors were measured every 30 s during a sustained maximal voluntary contraction (MVC).

Inherent Immune Cell Variation Within Colonic Segments Presents Challenges for Clinical Trial Design.

Background And Aims: Intestinal biopsy sampling during IBD trials represents a valuable adjunct strategy for understanding drug responses at the tissue level. Given the length and distinctive embryonic origins of the proximal and distal colon, we investigated whether inherent regional differences of immune cell composition could introduce confounders when sampling different disease stages, or pre/post drug administration. Here, we capitalise on novel mass cytometry technology to perform deep immunophenotyping of distinct healthy colonic segments, using the limited numbers of biopsies that can be harvested from patients.

Short-term isothermic heat acclimation elicits beneficial adaptations but medium-term elicits a more complete adaptation.

Purpose: To investigate the effects of 60 min daily, short-term (STHA) and medium-term (MTHA) isothermic heat acclimation (HA) on the physiological and perceptual responses to exercise heat stress.

Methods: Sixteen, ultra-endurance runners (female = 3) visited the laboratory on 13 occasions. A 45 min sub-maximal (40% W) cycling heat stress test (HST) was completed in the heat (40 °C, 50% relative humidity) on the first (HST), seventh (HST) and thirteenth (HST) visit.

Impairment of Cycling Capacity in the Heat in Well-Trained Endurance Athletes After High-Intensity Short-Term Heat Acclimation.

Purpose: To investigate the effects of short-term, high-intensity interval-training (HIIT) heat acclimation (HA).

Methods: Male cyclists/triathletes were assigned into either an HA (n = 13) or a comparison (COMP, n = 10) group. HA completed 3 cycling heat stress tests (HSTs) to exhaustion (60% Wmax; HST1, pre-HA; HST2, post-HA; HST3, 7 d post-HA).

Practical Torso Cooling During Soccer-Specific Exercise in the Heat.

Context: Precooling and midevent cooling of the torso using cooling vests can improve exercise performance in the heat with or without physiological changes; however, the effects of such cooling during intermittent exercise in the heat are unknown.

Objective: To investigate the effects of torso cooling during intermittent exercise in the heat (35°C, 50% relative humdity) on sprint performance and the physiological and perceptual responses to the exercise.

Design: Crossover study.

Implementation of Mass Cytometry as a Tool for Mechanism of Action Studies in Inflammatory Bowel Disease.

Background: Novel therapeutics for inflammatory bowel disease (IBD) are under development, yet mechanistic readouts at the tissue level are lacking. Techniques to assess intestinal immune composition could represent a valuable tool for mechanism of action (MOA) studies of novel drugs. Mass cytometry enables analysis of intestinal inflammatory cell infiltrate and corresponding molecular fingerprints with unprecedented resolution.

Passive Heat Exposure Alters Perception and Executive Function.

Findings regarding the influence of passive heat exposure on cognitive function remain equivocal due to a number of methodological issues including variation in the domains of cognition examined. In a randomized crossover design, forty-one male participants completed a battery of cognitive function tests [Visual Search, Stroop, Corsi Blocks and Rapid Visual Information Processing (RVIP) tests] prior to and following 1 h of passive rest in either hot (39.6 ± 0.

Nitrate Supplement Benefits Contractile Forces in Fatigued but Not Unfatigued Muscle.

Purpose: Evidence suggests dietary nitrate supplementation enhances low-frequency (≤20 Hz) involuntary, but not voluntary, forces in unfatigued human muscle. We investigated the hypotheses that nitrate supplementation would also attenuate low-frequency fatigue and the loss of explosive voluntary forces in fatigued conditions.

Methods: In a counterbalanced double-blinded order, 17 male participants completed two experimental trials after 7 d of dietary supplementation with either nitrate-rich (NIT) or nitrate-depleted (PLA) beetroot juice.