IMPORTANCE Sauna bathing is a health habit associated with better hemodynamic function; however, the association of sauna bathing with cardiovascular and all-cause mortality is not known. OBJECTIVE To investigate the association of 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. DESIGN, SETTING, AND PARTICIPANTS We performed a prospective cohort study (Finnish Kuopio Ischemic Heart Disease Risk Factor Study) of a population-based sample of 2315 middle-aged (age range, 42-60 years) men from Eastern Finland. Baseline examinations were conducted from March 1, 1984, through December 31, 1989. EXPOSURES Frequency and duration of sauna bathing assessed at baseline. RESULTS During a median follow-up of 20.7 years (interquartile range, 18.1-22.6 years), 190 SCDs, 281 fatal CHDs, 407 fatal CVDs, and 929 all-cause mortality events occurred. A total of 601, 1513, and 201 participants reported having a sauna bathing session 1 time per week, 2 to 3 times per week, and 4 to 7 times per week, respectively. The numbers (percentages) of SCDs were 61 (10.1%), 119 (7.8%), and 10 (5.0%) in the 3 groups of the frequency of sauna bathing. The respective numbers were 89 (14.9%), 175 (11.5%), and 17 (8.5%) for fatal CHDs; 134 (22.3%), 249 (16.4%), and 24 (12.0%) for fatal CVDs; and 295 (49.1%), 572 (37.8%), and 62 (30.8%) for all-cause mortality events. After adjustment for CVD risk factors, compared with men with 1 sauna bathing session per week, the hazard ratio of SCD was 0.78 (95% CI, 0.57-1.07) for 2 to 3 sauna bathing sessions per week and 0.37 (95% CI, 0.18-0.75) for 4 to 7 sauna bathing sessions per week (P for trend = .005). Similar associations were found with CHD, CVD, and all-cause mortality (P for trend Յ.005). Compared with men having a sauna bathing session of less than 11 minutes, the adjusted hazard ratio for SCD was 0.93 (95% CI, 0.67-1.28) for sauna bathing sessions of 11 to 19 minutes and 0.48 (95% CI, 0.31-0.75) for sessions lasting more than 19 minutes (P for trend = .002); significant inverse associations were also observed for fatal CHDs and fatal CVDs (P for trend Յ.03) but not for all-cause mortality events. CONCLUSIONS AND RELEVANCE 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 potential mechanism that links sauna bathing and cardiovascular health.

Background and Purpose-Systolic blood pressure (SBP) during exercise has been found to predict a future diagnosis of hypertension, coronary heart disease, and cardiovascular disease death. No studies have been conducted to show a relationship between SBP during exercise test and stroke. The aim of the present study was to study the associations between SBP rise, percent maximum SBP at 2 minutes after exercise, and the risk of stroke in a population-based sample of men with no prior coronary heart disease. Methods-SBP was measured every 2 minutes during and after the exercise test. The subjects were a population-based sample of 1026 men without clinical coronary heart disease, antihypertensive medication, or prior stroke at baseline. During an average follow-up of 10.4 years, there were 46 cases of stroke (38 ischemic strokes). Results-Men with SBP rise Ͼ19.7 mm Hg per minute of exercise duration had a 2.3-fold increased risk of any stroke and a 2.3-fold increased risk of ischemic stroke compared with men whose SBP rise was Ͻ16.1 mm Hg/min. Similarly, percent maximum SBP at 2 minutes after exercise (SBP at 2 minutes' recovery divided by maximum SBP) was associated (highest tertile) with a 4.6-fold increased risk of any stroke and a 5.2-fold increased risk of ischemic stroke. Conclusions-SBP rise during exercise and percent maximum SBP at 2 minutes after exercise were directly and independently associated with the risk of all stroke and ischemic stroke. Exercise SBP testing may be recommended as an additional tool in the prediction of future stroke.

Cardiorespiratory fitness had a strong, graded, inverse association with overall, CVD-related, and non-CVD-related mortality. Maximal oxygen uptake and exercise test duration represent the strongest predictors of mortality.

Sauna bathing, an activity that has been a tradition in Finland for thousands of years and mainly used for the purposes of pleasure and relaxation, is becoming increasingly popular in many other populations. Emerging evidence suggests that beyond its use for pleasure, sauna bathing may be linked to several health benefits, which include reduction in the risk of vascular diseases such as high blood pressure, cardiovascular disease, and neurocognitive diseases; nonvascular conditions such as pulmonary diseases; mortality; as well as amelioration of conditions such as arthritis, headache, and flu. The beneficial effects of sauna bathing on these outcomes have been linked to its effect on circulatory, cardiovascular, and immune functions. It has been postulated that regular sauna bathing may improve cardiovascular function via improved endothelium-dependent dilatation, reduced arterial stiffness, modulation of the autonomic nervous system, beneficial changes in circulating lipid profiles, and lowering of systemic blood pressure. This review summarizes the available epidemiological, experimental, and interventional evidence linking Finnish sauna bathing and its effects on cardiovascular outcomes and other disease conditions on the basis of a comprehensive search for observational studies, randomized controlled trials, and non-randomized controlled trials from MEDLINE and EMBASE from their inception until February 24, 2018. An overview of the postulated biological mechanisms underlying the associations between sauna bathing and its health benefits, areas of outstanding uncertainty, and implications for clinical practice is also provided.