Novel application of chemical cold packs for treatment of exercise-induced hyperthermia: a randomized controlled trial.

Objective: Heat-related illness is a common disease with significant morbidity and mortality. Despite no proven efficacy, application of chemical cold packs (CCP) to the skin overlying the large vessels of the neck, groin, and axillae is a traditional recommended cooling modality. The study objective was to compare the cooling rates of CCP applied to these traditional areas vs the glabrous skin surfaces of the cheeks, palms, and soles in exercise-induced hyperthermia.

Work volume and strength training responses to resistive exercise improve with periodic heat extraction from the palm.

Body core cooling via the palm of a hand increases work volume during resistive exercise. We asked: (a) "Is there a correlation between elevated core temperatures and fatigue onset during resistive exercise?" and (b) "Does palm cooling between sets of resistive exercise affect strength and work volume training responses?" Core temperature was manipulated by 30-45 minutes of fixed load and duration treadmill exercise in the heat with or without palm cooling. Work volume was then assessed by 4 sets of fixed load bench press exercises.

Light induces c-fos and per1 expression in the suprachiasmatic nucleus of arrhythmic hamsters.

Locomotor activity rhythms in a significant proportion of Siberian hamsters (Phodopus sungorus sungorus) become arrhythmic after the light-dark (LD) cycle is phase-delayed by 5 h. Arrhythmia is apparent within a few days and persists indefinitely despite the presence of the photocycle. The failure of arrhythmic hamsters to regain rhythms while housed in the LD cycle, as well as the lack of any masking of activity, suggested that the circadian system of these animals had become insensitive to light.

Heat extraction through the palm of one hand improves aerobic exercise endurance in a hot environment.

In situations where the accumulation of internal heat limits physical performance, enhanced heat extraction from the body should improve performance capacity. The combined application of local subatmospheric pressure (35-45 mmHg) to an entire hand (to increase blood volume) and a heat sink (18-22 degrees C) to the palmar surface were used to draw heat out of the circulating blood. Subjects walked uphill (5.

Light pulses do not induce c-fos or per1 in the SCN of hamsters that fail to reentrain to the photocycle.

Circadian activity rhythms of most Siberian hamsters (Phodopus sungorus sungorus) fail to reentrain to a 5-h phase shift of the light-dark (LD) cycle. Instead, their rhythms free-run at periods close to 25 h despite the continued presence of the LD cycle. This lack of behavioral reentrainment necessarily means that molecular oscillators in the master circadian pacemaker, the SCN, were unable to reentrain as well.

Glucocorticoids influence brain glycogen levels during sleep deprivation.

We investigated whether glucocorticoids [i.e., corticosterone (Cort) in rats] released during sleep deprivation (SD) affect regional brain glycogen stores in 34-day-old Long-Evans rats.