Effect of a single finnish sauna session on white blood cell profile and cortisol levels in athletes and non-athletes.
Level 3 - non-randomized controlled study
Non-randomized comparative physiological study
PubMed 24511348 · doi:10.2478/hukin-2013-0075
What was done
Nine trained male middle-distance runners and nine male non-athletes underwent a Finnish sauna protocol (temperature 96 ± 2°C, relative humidity 15 ± 3%) consisting of 15-minute sessions until rectal core temperature increased by 1.2°C, followed by a 2-minute cool down with 19–20°C water. Body mass, rectal temperature (measured every 5 minutes), serum total protein, white blood cell profile, and cortisol levels were evaluated before and after the session.
What was found
Sauna exposure led to higher body mass loss and plasma volume changes in athletes compared to non-athletes. Following the session, white blood cell, lymphocyte, neutrophil, and basophil counts increased in all subjects, with higher increments in leukocyte and monocyte counts observed in athletes compared to non-athletes. The abstract does not provide exact numerical values, effect sizes, p-values, or specific findings for cortisol levels.
Why it matters
The study shows that acute thermal stress from Finnish sauna bathing induces transient leukocytosis, with trained athletes displaying a more pronounced white blood cell mobilization than untrained individuals.
Limits
The study is limited by a very small sample size (n = 18) restricted to males. The abstract does not report specific numerical values, measures of variance, or results for cortisol. Additionally, the clinical significance and duration of the immune changes were not assessed.
Cited by
- supports Sauna use increases white blood cell, lymphocyte, and neutrophil counts in both trained and non-trained athletes.