Author(s): STRAZDAITE, E., SKURVYDAS, A., DADELIENE, R., AUKSTIKALNIS, T., ISTOMINA, N., ARMANAVICIUTE, A., GROSAS, P., MAJAUSKIENE, D. , Institution: VILNIUS UNIVERSITY, Country: LITHUANIA, Abstract-ID: 1414

INTRODUCTION:
Whole-body heating, including sauna bathing, may mimic the benefits of physical exercise in preventing cardiometabolic diseases. Although positive effects of sauna use have been reported, it remains unclear whether these benefits arise from sauna bathing itself or are enhanced when combined with physical activity in habitual routines (Lee et al., 2022). The present study investigated whether passive heat exposure is associated with cardiometabolic health and factors contributing to an extended healthspan.
METHODS:
A representative cross-sectional survey of 941 Lithuanian adults (of which 710 self-identified as female and 231 as male), aged 18–64 years, was conducted as part of the government-funded project THERMOHORMESIS (No. S-MIP-24-67). Participants were categorized by sauna use frequency (53% non-users vs. 47% sauna users) and were compared across self-reported sociodemographic factors, anthropometric and cardiometabolic indicators, physical activity, daily step counts, engagement in sports, sedentary time, and other lifestyle parameters, using validated questionnaires. Data were analyzed using age- and sex-adjusted ANCOVA and logistic regression analyses.
RESULTS:
Sauna use was significantly associated with higher physical activity across all intensities. After adjustment, sauna use remained independently associated with higher levels of light (women: Cohen’s d = 0.44, 95% CI [0.26, 0.62], men: Cohen’s d = 0.33, 95% CI [0.05, 0.61]; p-value = 0.026), moderate (women: Cohen’s d = 0.50, 95% CI [0.32, 0.68], men: Cohen’s d = 0.33, 95% CI [0.05, 0.61]; p-value = 0.026), vigorous (women: Cohen’s d = 0.63, 95% CI [0.45, 0.81], men: Cohen’s d = 0.51, 95% CI [0.23, 0.79]; p-value < 0.001), and moderate-to-vigorous (women: Cohen’s d = 0.73, 95% CI [0.55, 0.91], men: Cohen’s d = 0.56, 95% CI [0.28, 0.84]; p-value < 0.001) physical activity. Frequent sauna users were also more likely to engage in regular sports activities, whereas non-users reported lower participation. Daily step counts and sedentary time did not differ significantly by sauna frequency. Notably, higher sauna frequency was associated with better overall health exclusively among women (Cohen’s d = 0.21, 95% CI [0.03, 0.39]; p-value = 0.018).
CONCLUSION:
These findings suggest that sauna use is unlikely to exert an independent cardiometabolic effect in the general adult population, but rather represents a marker of an overall health-oriented lifestyle characterized by higher physical activity and enhanced behavioural regulation.

REFERENCE: Lee E, Kolunsarka I, Kostensalo J, Ahtiainen JP, Haapala EA, Willeit P, Kunutsor SK, Laukkanen JA. Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial. Am J Physiol Regul Integr Comp Physiol. 2022 Sep 1;323(3):R289-R299. doi: 10.1152/ajpregu.00076.2022. Epub 2022 Jul 4. PMID: 35785965; PMCID: PMC9394774.