Endocrine effects of repeated sauna bathing

Abstract

Ten healthy male and seven female volunteers were exposed to dry heat (in a Finnish sauna 80 degrees C) 1 h twice a day for 7 days. The levels of ACTH in plasma, cortisol, TSH, thyroid hormones, testosterone, gonadotropins, prolactin and GH in serum and urinary excretion of catecholamines were determined before the experiment, and on the first, third and seventh days. Females participated only in prolactin studies. During the experiments there were no statistically significant changes in serum thyroid hormones, TSH, testosterone, FSH and LH levels. Serum cortisol and plasma ACTH decreased and urinary catecholamine increased slightly at the end of the experiment (P less than 0.05). Serum GH and prolactin in males exhibited 16- and 2.3-fold increases (P less than 0.01), respectively. In females serum prolactin rose over four-fold (P less than 0.01). The GH rise in response to hyperthermia declined after the third day but prolactin remained elevated at the end of the experiments in males. The release of prolactin in females was also high and may be associated with the transient amenorrhoea that occurred in five out of seven subjects after the experiment. The increased release of prolactin and perhaps that of GH may be associated to the heat-exposure-induced dehydration.

The effects of face cooling on the prolactin response and subjective comfort during moderate passive heating in humans

“…External heat loading has previously been shown to be a potent prolactinotrophic stimulus (Mills & Robertshaw, 1981; Christensen et al 1985; Leppaluoto et al 1986; Brisson et al 1991); however, there have also been reports of heat exposure having no effect on plasma prolactin (Follenius et al 1979; Brandenberger et al 1979). An explanation for this might be the differing degrees to which core temperature had risen from baseline, and Brisson et al (1991) argued that a certain body temperature threshold must be reached for heat loads to induce significant changes in blood prolactin.…”

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The effects of physical therapeutic agents on serum levels of stress hormones in patients with osteoarthritis

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