Sauna

Sauna use, sometimes referred to as sauna bathing, is characterized by short-term passive exposure to high temperatures, typically ranging from 45 to 100 degrees C, which elicits mild hyperthermia and a thermoregulatory response. ^[1] Sauna bathing is a tradition rooted in Finnish culture used for thousands of years for leisure and relaxation, but emerging evidence links it to several health benefits beyond pleasure. ^[2] The most commonly used and widely studied form is the Finnish sauna, characterized by high temperatures ranging from 80 to 100 degrees C and dry air with relative humidity varying from 10 to 20 percent. ^[3]

Repeated sauna use acclimates the body to heat and optimizes its response to future exposures, likely through the biological phenomenon known as hormesis. ^[1] 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. ^[2] The beneficial effects of passive heat therapies may be linked to their anti-inflammatory, cytoprotective, and antioxidant properties and synergistic effects on neuroendocrine, circulatory, cardiovascular, and immune function. ^[3]

Large, prospective, population-based cohort studies of sauna users have identified strong dose-dependent links between sauna use and reduced morbidity and mortality. ^[1] A systematic review and meta-analysis found that, compared with control conditions, heat therapy reduced mean arterial pressure by 5.86 mmHg, systolic blood pressure by 3.94 mmHg, and diastolic blood pressure by 3.88 mmHg, and improved flow-mediated dilatation by 1.95 percent. ^[4] A meta-analysis of sauna treatment on cardiovascular function reported acute reductions of 5.55 mmHg in systolic and 6.50 mmHg in diastolic blood pressure, and short-term improvements including a 3.27 percent increase in left ventricular ejection fraction. ^[5] A systematic review of 40 clinical studies involving 3855 participants reported that most studies found beneficial health effects, but only 13 were randomized controlled trials and most were small, indicating that higher-quality evidence is still needed. ^[6] Several observational and interventional studies suggest that regular sauna bathing reduces the incidence of vascular and nonvascular diseases such as hypertension, cardiovascular disease, dementia

Passive heat therapy, notably Finnish sauna, is emerging as a potentially powerful and holistic strategy for promoting health and extending the healthspan in all populations. ^[3] Sauna-induced physiological responses closely parallel the adaptations observed during aerobic exercise, offering an adjunctive option for patients who face barriers to traditional exercise regimens. ^[8] Sauna bathing is well tolerated by most healthy adults and children, but contraindications include unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis, and alcohol consumption during bathing increases the risk of hypotension, arrhythmia, and sudden death. ^[9]