Two nights of sleep deprivation with or without energy restriction does not impair the thermal response to cold.

Purpose: In persons completing exhaustive daily exercise, sleep and energy restriction have been highlighted as risk factors for hypothermia in cold environments. The present study therefore sought to determine the effect of sleep deprivation (SDEP), with and without energy restriction, on the thermal response to cold.

Methods: In a random order, ten recreationally active men (mean ± SD: age 25 ± 6 years, body fat 17 ± 5 %) completed three 53 h trials: a control (CON: 436 min/night sleep), SDEP (0 min sleep), and sleep deprivation and energy restriction (SDEP + ER: 0 min sleep and 10% daily energy requirements).

High altitude impairs in vivo immunity in humans.

The aim was to assess the effect of high altitude on the development of new immune memory (induction) using a contact sensitization model of in vivo immunity. We hypothesized that high-altitude exposure would impair induction of the in vivo immune response to a novel antigen, diphenylcyclopropenone (DPCP). DPCP was applied (sensitization) to the lower back of 27 rested controls at sea level and to ten rested mountaineers 28 hours after passive ascent to 3777 m.

Three nights of sleep deprivation does not alter thermal strain during exercise in the heat.

Purpose: Individuals exposed to total sleep deprivation may experience an increased risk of impaired thermoregulation and physiological strain during prolonged physical activity in the heat. However, little is known of the impact of more relevant partial sleep deprivation (PSD). This randomized counterbalanced study investigated the effect of PSD on thermal strain during an exercise-heat stress.

Exercise-induced stress inhibits both the induction and elicitation phases of in vivo T-cell-mediated immune responses in humans.

Little is known about the influence of exercise on induction and elicitation phases of in vivo immunity in humans. We used experimental contact-hypersensitivity, a clinically relevant in vivo measure of T cell-mediated immunity, to investigate the effects of exercise on induction and elicitation phases of immune responses to a novel antigen. The effects of 2 h-moderate-intensity-exercise upon the induction (Study One) and elicitation of in vivo immune memory (Study Two) to diphenylcyclopropenone (DPCP) were examined.

The effects of two nights of sleep deprivation with or without energy restriction on immune indices at rest and in response to cold exposure.

The purpose of the study was to determine the effects of two nights of sleep deprivation with or without energy restriction on immune indices at rest and in response to cold exposure. On three randomised occasions ten males slept normally [mean (SD): 436 (21) min night(-1); CON], were totally sleep-deprived (SDEP), or were totally sleep-deprived and 90% energy-restricted (SDEP + ER) for 53 h. After 53 h (1200 h) participants performed a seated cold air test (CAT) at 0.