Do training-dependent differences in perspiration exist between healthy and atopic subjects?

Sweating (perspiratio sensibilis) serves predominantly for thermoregulation and is triggered, among other stimuli, by physical stress. Although consensus on sex-dependent differences in sweating has not been reached so far and recent studies revealing abnormal diminution of the sweating capacity in atopic subjects are mainly based on heat exposure experiments, the influence of endurance training on perspiration in atopics has not yet been evaluated. Using a special sweat collector device reliable even during intensive body movement, we compared the sweat production of age-matched male and female healthy controls (14 m, 10 f) to that of in-patients with atopic eczema (AE: 14 m, 10 f) during and 5 min after physical exercise (30 min) with a bicycle ergometer under standardized experimental conditions. The individual stress limit was determined by a previous endurance test including repeated lactate blood level measurements and continuous heart rate control. Informed consent was obtained from every participant in the study. One half of both the patients and the controls underwent three week endurance training, and the preceding sweat measurements were repeated in all patients and controls after the training period under identical conditions. On average, the healthy males perspired nearly twice as much as the corresponding females (p < 0.0016). Highly significant mean differences of maximum sweat secretion rates were also found between the atopics and the controls. Healthy individuals of both sexes perspired nearly three times as much as did the patients with AE (males: p < 0.0004; females: p < 0.00009). Among the atopics there were remarkable, yet statistically insignificant, sexual differences in sweat production. After three weeks, sweating rates were similar to the initial ones in the training group as well as in the non-trained control group. Gender differences in perspiration do not only exist between healthy males and females but also in patients with atopic skin disorder, yet the latter ones at significantly lower levels as compared to healthy control subjects. No influence of a three-week-exercise phase on sweat secretion in atopics and controls could be proven. For designing further studies on intra- or intersexual differences of drug-independent perspiration, standardized physical stress can be recommended as an experimental prerequisite for sweat measurements.