Sauna bath reduces blood pressure in healthy adult volunteers: A meta-analysis of RCTs and quasi-experimental studies

Abstract

BackgroundModifiable risk factors cause over 70% of cardiovascular diseases worldwide. Sauna bath is an effective treatment for patients with hypertension which is a known risk factor for cardiovascular disease and premature death. Objective of the current review is to evaluate the current evidences available on the effect of sauna bath and blood pressure on normotensive individuals. MethodElectronic databases (such as PubMed, Prospero, Scopus, and Cochrane Library) were searched since inception until January 2021. Studies investigating the effect of sauna bath on blood pressure in healthy volunteers were included. Primary outcome measures were changes in systolic (SBP) and diastolic blood (DBP) pressure after sauna bath. Standardized mean difference (SMD) and 95% CIs were calculated using a random-effects model. ResultWe included six studies conducted among 76 normotensive participants (average age of 29 – 33 years) with the duration of 10mins to 1hour and a follow up of 7 days to 3 months. Among the included studies, the pooled effect of SBP changes does not favour sauna bathing (SMD: 0.23, 95%CI: -2.29-3.39, I2:83%, p<0.01) whereas DBP changes showed a positive effect of sauna bath among the healthy volunteers with considerable heterogeneity (SMD: -1.01, 95%CI: --5.76-3.74, I2:83%, p<0.01). Subgroup analysis on duration and frequency of bathing also revealed the same findings. ConclusionSauna bath, could be considered as a promising tool for primary prevention of hypertension and related cardiovascular ailments and thus achieving the global target of non-communicable disease.