Sauna Bathing & Cardiorespiratory Fitness on Cardiovascular Mortality Risk

Published in Annals of Medicine – Volume 50, 2018 – Issue 2
Joint associations of sauna bathing and cardiorespiratory fitness on cardiovascular and all-cause mortality risk: a long-term prospective cohort study

ABSTRACT

Purpose: We aimed to evaluate the joint impact of cardiorespiratory fitness (CRF) and frequency of sauna bathing (FSB) on the risk of cardiovascular and all-cause mortality.

Design: CRF measured by respiratory gas analyses and sauna exposure were assessed at baseline in a prospective study of 2277 men. CRF was categorized as low and high (median cut-offs) and FSB as low and high (2 and 3–7 sessions/week, respectively).

Results: During a median follow-up of 26.1 years, 520 cardiovascular and 1124 all-cause deaths occurred. Comparing high versus low CRF, the multivariate-adjusted hazard ratios (HRs) 95% CIs for cardiovascular and all-cause mortality were 0.51 (0.41–0.63) and 0.65 (0.57–0.75), respectively.

Comparing high versus low FSB, the corresponding HRs were 0.74 (0.59–0.94) and 0.84 (0.72–0.97), respectively. Compared to low CRF & low FSB, the HRs of CVD mortality for high CRF & high FSB; high CRF & low FSB; and low CRF & high FSB were 0.42 (0.28–0.62), 0.50 (0.39–0.63) and 0.72 (0.54–0.97), respectively. For all-cause mortality, the corresponding HRs were 0.60 (0.48–0.76), 0.63 (0.54–0.74) and 0.78 (0.64–0.96), respectively.

Conclusions: A combination of high CRF and frequent sauna bathing confers stronger long-term protection on mortality outcomes compared with high CRF or high FSB alone.

KEY MESSAGES:

• Cardiorespiratory fitness (CRF) and frequency of sauna bathing are independently associated with reduced mortality risk; a combination of good CRF and frequent sauna bathing may confer additional survival benefits.

• In a population-based prospective cohort study, a combination of high CRF levels and frequent sauna bathing (3–7 sessions per week) was associated with a substantial risk reduction in fatal cardiovascular and all-cause mortality events compared with good CRF or frequent sauna bathing alone.

• A combination of good fitness levels produced by aerobic exercises and frequent sauna bathing may have added health benefits and confer more protection on the risk of mortality.