Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events | Journal Scan
Study Questions:
What is the association of the frequency and duration of sauna bathing with the risk of sudden cardiac death (SCD), fatal coronary heart disease (CHD), fatal cardiovascular disease (CVD), and all-cause mortality?
Methods:
A prospective cohort study (Finnish Kuopio Ischemic Heart Disease Risk Factor Study) was conducted in a population-based sample of 2,315 middle-aged (age range, 42-60 years) men from Eastern Finland. Baseline examinations were conducted from March 1, 1984, through December 31, 1989. Sauna bathing sessions were divided into 1 time per week, 2-3 times per week, and 4-7 times per week.
Results:
Mean age was 53 years, body mass index 26.9 kg/m2, blood pressure 134/88 mm Hg, peak V02 30.2 ml/kg/min, and physical activity 372 kcal/day. In addition, 30% were smokers, 5% were diabetics, 24% had CHD, 34% had hypertension, and 7.5% had chronic heart failure. During a median follow-up of 20.7 years (interquartile range, 18.1-22.6 years), 190 SCD, 281 fatal CHD, 407 fatal CVD, and 929 all-cause mortality events occurred. The frequency of SCDs was 10.1%, 7.8%, and 5.0% by group of sauna bathing frequency, from lowest to highest. The results were similar for fatal CHD at 14.9%, 11.5%, and 8.5%; for fatal CVD, 22.3%, 16.4%, and 12.0%; and for all-cause mortality, 49.1%, 37.8%, and 30.8% for all-cause mortality events. After adjustment for CVD risk factors, compared with men with one sauna bathing session per week, the hazard ratio of SCD was 0.78 (95% CI, 0.57-1.07) for 2-3 sauna bathing sessions per week and 0.37 (95% confidence interval [CI], 0.18-0.75) for 4-7 sauna bathing sessions per week (p for trend = 0.005). Similar associations were found with CHD, CVD, and all-cause mortality (p for trend ≤ 0.005). Compared with men having a sauna bathing session of <11 minutes, the adjusted hazard ratio for SCD was 0.93 (95% CI, 0.67-1.28) for sauna bathing sessions of 11-19 minutes and 0.48 (95% CI, 0.31-0.75) for sessions lasting more than 19 minutes (p for trend = 0.002); significant inverse associations were also observed for fatal CHD and fatal CVD (p for trend ≤ 0.03), but not for all-cause mortality events.
Conclusions:
Increased frequency of sauna bathing is associated with a reduced risk of SCD, CHD, CVD, and all-cause mortality. Further studies are warranted to establish the effects in other populations and the mechanism that links sauna bathing and cardiovascular health.
Perspective:
Hot sauna in patients with heart disease can be associated with hypotension and increase in CV events, particularly when combined with sudden cold water pools or showers. However, when done safely as in this study, it simulates low- and moderate-intensity physical exercise training and improves endothelial function. When used >2 times per week, sauna bathing increases left ventricular ejection fraction and lowers blood pressure.
Keywords: Primary Prevention, Blood Pressure, Blood Pressure Determination, Body Mass Index, Cardiovascular Diseases, Coronary Disease, Death, Sudden, Cardiac, Diabetes Mellitus, Heart Failure, Exercise, Hypertension, Hypotension, Risk Factors, Steam Bath, Mortality, Prospective Studies, Follow-Up Studies
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