Non-invasive assessment of integrated cardiorespiratory network dynamics after physiological stress in humans.

Visualizing the exchange of information between different components of the cardiorespiratory system is essential for understanding physiological control and is valuable for monitoring individuals in various clinical settings and extreme environments. Network physiology is a multidisciplinary field that explores the collective behaviour of physiological systems, offering a novel approach to understanding these complex interactions. The present study aimed to develop a non-invasive method to visualize the cardiorespiratory network under control conditions and after isolated or combined exposure to hypoxia, exercise and sleep-deprivation (total or partial).

Effect of condensed heat acclimation on thermophysiological adaptations, hypoxic cross-tolerance, exercise performance, and deacclimation.

Short duration heat acclimation (HA) (≤5 daily heat exposures) elicits incomplete adaptation compared with longer interventions, possibly due to the lower accumulated thermal "dose." It is unknown if matching thermal "dose" over a shorter timescale elicits comparable adaptation to a longer intervention. Using a parallel-groups design, we compared: "condensed" HA (CHA; = 17 males) consisting of 4 × 75 min·day heat exposures [target rectal temperature () 38.

The effects of sleep deprivation, acute hypoxia, and exercise on cognitive performance: A multi-experiment combined stressors study.

Introduction: Both sleep deprivation and hypoxia have been shown to impair executive function. Conversely, moderate intensity exercise is known to improve executive function. In a multi-experiment study, we tested the hypotheses that moderate intensity exercise would ameliorate any decline in executive function after i) three consecutive nights of partial sleep deprivation (PSD) (Experiment 1) and ii) the isolated and combined effects of a single night of total sleep deprivation (TSD) and acute hypoxia (Experiment 2).

The effects of normobaric and hypobaric hypoxia on cognitive performance and physiological responses: A crossover study.

This partially randomised controlled, crossover study sought to investigate the effects of normobaric hypoxia (NH) and hypobaric hypoxia (HH) on cognitive performance, the physiological response at rest and after a 3-min step-test. Twenty healthy participants (10 females and 10 males, 27.6±6.

Head pre-cooling improves 5-km time-trial performance in male amateur runners in the heat.

This study aimed to evaluate the effect of head pre-cooling on the 5-km time-trial performance of amateur runners in the heat. In a counterbalanced design, 15 male amateur runners (22.6 ± 3.

A network physiology approach to oxygen saturation variability during normobaric hypoxia.

New Findings: What is the central question of this study? What is the physiological interpretation of fluctuations observed during normobaric hypoxia in healthy individuals? What is the main finding and its importance? There is a significant flow of information between and other cardio-respiratory time series during graded hypoxia. Analysis of the pattern of variations has potential for non-invasive assessment of the engagement of respiratory control system in health and disease.

Abstract: Peripheral capillary oxygen saturation ( ) exhibits a complex pattern of fluctuations during hypoxia.

Effects of Normobaric Hypoxia on Oxygen Saturation Variability.

The study is the first to evaluate the effects of graded normobaric hypoxia on SpO variability in healthy individuals. Twelve healthy males (mean [standard deviation] age 22 [4] years) were exposed to four simulated environments (fraction of inspired oxygen [O]: 0.12, 0.

Cognitive performance is associated with cerebral oxygenation and peripheral oxygen saturation, but not plasma catecholamines, during graded normobaric hypoxia.

New Findings: What is the central question of this study? What are the mechanisms responsible for the decline in cognitive performance following exposure to acute normobaric hypoxia? What are the main findings and their importance? We found that (1) performance of a complex central executive task (n-back) was reduced at 0.12; (2) there was a strong correlation between performance of the n-back task and reductions in and cerebral oxygenation; and (3) plasma adrenaline, noradrenaline, cortisol and copeptin were not correlated with cognitive performance.

Abstract: It is well established that hypoxia impairs cognitive function; however, the physiological mechanisms responsible for these effects have received relatively little attention.