Residual effects of short-term whole-body cold-water immersion on the cytokine profile, white blood cell count, and blood markers of stress.

One of the most challenging environmental extremes is immersion in cold/icy water, and consequent common assumption is that even a brief exposure to cold can lead to cold-related illnesses. The increase in the concentrations of the stress hormones cortisol, epinephrine (Epi), and norepinephrine (NE) in response to acute cold stress are thought to suppress the release of proinflammatory cytokines. No previous study has explored the residual consequences of whole-body short-term cold-water immersion (CWI; 14 °C for 10 min) on the immune response in healthy non-acclimated young adult men (aged 20-30 years).

Recovering body temperature from acute cold stress is associated with delayed proinflammatory cytokine production in vivo.

A poor outcome of whole-body hypothermia often results from a late complication, rather than from acute effects of hypothermia. A low body (cell) temperature or the increase in the concentrations of the stress hormones cortisol, epinephrine, and norepinephrine in response to acute cold stress have been proposed as potent proinflammatory cytokine suppressant. In the current study, we tested the hypothesis that the recovery of body temperature from a whole-body intermittent cold-water immersion (CWI, at 13-14 °C for a total 170 min) is associated with a delayed response of proinflammatory cytokines in young healthy men.

Exposure to total 36-hr sleep deprivation reduces physiological and psychological thermal strain to whole-body uncompensable passive heat stress in young adult men.

Total sleep deprivation (TSD) is associated with endothelial dysfunction and a consequent decrease in vascular reactivity and increase in peripheral vascular resistance. These effectors compromise the body's ability to thermoregulate in hot and cold stress conditions. We investigated heat-unacclimated young adult men (26 ± 2 years) to determine whether 36 hr of TSD compared to an 8 or 4-hr sleep condition, would suppress the responses of the autonomic system (body rectal temperature [T ], heart rate [HR], root mean square of successive interbeat intervals, physiological strain, blood pressure [BP], circulating blood catecholamines, sweating rate and subjective sensations) to whole-body uncompensable passive heat stress in traditional Finnish sauna heat (T  = 80-90°C, rh = 30%).

Effects of severe whole-body hyperthermia on ovarian hormone and extracellular Hsp72 responses in young adult women.

Although acute thermal stress appears to be one of the most effective stressors that increase the intra- and extracellular concentrations of heat shock protein 72 (Hsp72), 17β-estradiol has been shown to inhibit heat-induced Hsp72 expression. To determine whether severe whole-body hyperthermia (increase in rectal temperature up to 39.5 °C) induced by lower-body heating is a sufficient stimulus to modulate hormonal (17β-estradiol, progesterone, prolactin, epinephrine, and norepinephrine) and extracellular Hsp72 responses, we investigated young adult women (21 ± 1 yr).

Motor performance is preserved in healthy aged adults following severe whole-body hyperthermia.

Healthy aging is associated with a progressive decline in motor performance and thermoregulatory efficiency. Functional consequences of severe whole-body hyperthermia on neurophysiological functions in healthy aged men have not been investigated. To determine whether severe whole-body hyperthermia (increase in rectal temperature of about 2.

Three different motor task strategies to assess neuromuscular adjustments during fatiguing muscle contractions in young and older men.

Healthy aging is associated with a marked decline in motor performance. The functional consequences of applying varying novel or unexpected motor stimuli during intermittent isometric prolonged (fatiguing) motor tasks for lower limb neuromuscular fatigability and steadiness, perception of effort, and blood markers of stress in healthy aged men compared with young men have not been investigated. The participants in this study were 15 young men (aged 22 ± 4 years) and 10 older men (aged 67 ± 6 years).

Psychological and Physiological Biomarkers of Neuromuscular Fatigue after Two Bouts of Sprint Interval Exercise.

The main aim of our study was to determinate whether a repeated bout (RB) (vs. first bout [FB]) of sprint interval cycling exercise (SIE) is sufficient to mitigate SIE-induced psychological and physiological biomarker kinetics within 48 h after the exercise. Ten physically active men (age, 22.

Physiological and Psychological Responses during Exercise and Recovery in a Cold Environment Is Gender-Related Rather Than Fabric-Related.

We evaluated gender-specific effects of two types of undergarments on exercise-induced physiological and psychological stress and subsequent recovery in cold conditions for male and female participants. Ten healthy men and eleven healthy women (25.0 ± 1.

Brief Rewarming Blunts Hypothermia-Induced Alterations in Sensation, Motor Drive and Cognition.

It is well known that cold exposure experienced during occupational or recreational activities may adversely affect motor, cognitive performance, and health. Most research has used prolonged passive external rewarming modalities and focused on the direct effects on the kinetics of physiological and psychological responses in hypothermic subjects. However, the brief whole body rewarming effects on physiological and psychological responses in parallel with functional consequences on cognitive and neurophysiological functions have not been investigated.

Similar cold stress induces sex-specific neuroendocrine and working memory responses.

Background: Men have higher cold-induced neuroendocrine response than women; nevertheless, it is not known whether a different stress hormone rise elicits different effects on cognition during whole body cooling.

Objective: The objective was to compare the effect of cold-induced neuroendocrine responses on the performance of working memory sensitive tasks between men and women.

Materials And Methods: The cold stress continued until rectal temperature reached 35.

Two strategies for the acute response to cold exposure but one strategy for the response to heat stress.

Purpose: The main aim of this study was to compare physiological and psychological reactions to heat stress between people who exhibited fast cooling (FC, n = 20) or slow cooling (SC; n = 20) responses to 14 °C cold water immersion.

Methods: Forty healthy young men (19-25 years old) were recruited to this study based on their tolerance to cold exposure (FC versus SC). The heat stress was induced using immersion in bath water at 43-44 °C.

Two strategies for response to 14 °C cold-water immersion: is there a difference in the response of motor, cognitive, immune and stress markers?

Here, we address the question of why some people have a greater chance of surviving and/or better resistance to cold-related-injuries in prolonged exposure to acute cold environments than do others, despite similar physical characteristics. The main aim of this study was to compare physiological and psychological reactions between people who exhibited fast cooling (FC; n = 20) or slow cooling (SC; n = 20) responses to cold water immersion. Individuals in whom the T(re) decreased to a set point of 35.

Effects of whole body heat stress on sublingual microcirculation in healthy humans.

Purpose: To assess the effect of whole body heat stress on sublingual microcirculation.

Methods: Fourteen apparently healthy subjects participated in the study. Passive body heating was performed by immersing the subjects up to the waist in a water bath at 44 °C continuously until a rectally obtained core temperature of 39.

Time course of physiological and psychological responses in humans during a 20-day severe-cold-acclimation programme.

The time course of physiological and psychological markers during cold acclimation (CA) was explored. The experiment included 17 controlled (i.e.

Effects of estrogen fluctuation during the menstrual cycle on the response to stretch-shortening exercise in females.

The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n = 18; age = 20.2 ± 1.

The effect of temperature on amount and structure of motor variability during 2-minute maximum voluntary contraction.

Introduction: In this study, we questioned whether local cooling of muscle or heating involving core and muscle temperatures are the main indicators for force variability.

Methods: Ten volunteers performed a 2-min maximum voluntary contraction (MVC) of the knee extensors under control (CON) conditions after passive heating (HT) and cooling (CL) of the lower body.

Results: HT increased muscle and rectal temperatures, whereas CL lowered muscle temperature but did not affect rectal temperature.

The effect of heating and cooling on time course of voluntary and electrically induced muscle force variation.

Unlabelled: The aim of this study was to investigate the effect of heating and cooling on time course of voluntary and electrically induced muscle force variation.

Material And Methods: Ten volunteers performed 50 maximal voluntary and electrically induced contractions of the knee extensors at an angle of 120 degrees under the control conditions and after passive lower body heating and cooling in the control, heating, and cooling experiments. Peak torque, torque variation, and half-relaxation time were assessed during the exercise.

The effect of two kinds of T-shirts on physiological and psychological thermal responses during exercise and recovery.

The aim of this study was to investigate the physiological and psychological responses during and after high-intensity exercise in a warm and humid environment in subjects wearing shirts of different fabrics. Eight healthy men exercised on two separate occasions, in random order, wearing two types of long-sleeve T-shirt: one made of polyester (PES) and the other of cotton fabric (CT). They performed three 20 min exercise bouts, with 5 min rest between each, and then rested in a chair for 60 min to recover.