As in Russia, the Scandinavian countries are very fond of the sauna, especially in winter, when it can be alternated with swimming in ice water or snow. In addition to strengthening the cardiovascular system and promoting weight loss, contrast procedures can make the body resistant to extreme temperatures, scientists from Denmark have found.
Researchers at the University of Copenhagen have suggested that regular sauna use and cold water swimming may affect the ability of brown fat to burn energy and produce heat, thereby “accustoming” the body to comfortably endure both extreme heat and cold.
Brown adipose tissue provides heat production in the body and is involved in fat burning. This fat also helps control blood sugar, so the activity of brown adipose tissue can help prevent the development of diabetes. With age or overweight, the volume of brown fat decreases.
The study involved eight young men who for two years practiced swimming in cold water and a sauna, or only “ice swimming” once a week for two years. Eight more participants of the same age group were included in the control group – they did not go in for winter swimming and did not go to the sauna.
Scientists assumed that the volume of brown fat in ice water and hot saunas lovers would increase, but according to the results of the study, they saw a different effect: the volunteers had significantly improved thermoregulation. To evaluate the effect of such treatments on cold resistance, volunteers from both groups were asked to dip their hand in ice-cold water for three minutes. Compared to the control group, all participants showed minimal changes in heart rate and blood pressure. They also had a higher skin temperature, which means a higher level of adaptation to heat loss in the body.
Under the influence of cold, the activity of brown adipose tissue increased in both groups, however, among the lovers of “winter swimming” and the sauna there was a higher production of heat and energy consumption.
“They burned more calories during cooling, possibly due to increased heat production,” the study authors said.
The scientists also assessed the body’s thermoregulation of all participants during the day at a comfortable temperature. It turned out that supporters of contrast procedures have a lower body temperature on average, which is potentially a sign of adaptation to heat due to frequent visits to the sauna.
The authors of the study noted that these conclusions cannot be considered definitive due to the small sample of participants, moreover, of the same gender and age. However, these results potentially indicate that increasing the activity of brown adipose tissue can significantly reduce the risk of metabolic disorders.