Physiological Effects of Sauna on Renal and Cardio-Circulatory Functions: A Study Conducted in Six Sauna Facilities in the City of Bujumbura, Burundi

Introduction: Sauna bathing is well known for its cardiovascular and metabolic effects. However, limited data exist on its physiological impact in sub-Saharan Africa, particularly in Burundi. This study aims to evaluate the physiological effects of sauna baths on renal and cardio-circulatory functions. Methods: A cross-sectional study was conducted among users of six sauna facilities in Bujumbura. Characteristics of the sauna facilities were documented. Anthropometric, sociodemographic, cardiovascular (blood pressure, heart rate), and renal parameters (urea, creatinine) were measured before and after a sauna session. Collected physiological parameters were statistically analyzed using Student’s t-test or Wilcoxon test to compare paired means. The chi-square test and Welch’s test were used to assess associations and to compare means between independent groups, respectively. Statistical significance was set at p < 0.05. Results: Six sauna rooms were assessed and showed limited surface area, poor ventilation, and exclusive use of wood heating. Forty-nine participants, predominantly male, were included. Sauna exposure led to a significant decrease in mean arterial pressure (p = 0.027), whereas systolic and diastolic blood pressures showed non-significant reductions. Heart rate tended to increase slightly, while body weight did not significantly vary. Renal and hematological parameters remained stable, with no significant changes in creatinine, urea, hemoglobin, platelets, or leukocytes. Conclusions: Findings suggest that sauna exposure was associated with a mild acute cardiovascular effect characterized by reduced mean arterial pressure, while renal and hematological functions remained stable, suggesting that short-term sauna use is generally well tolerated in healthy individuals. This indicates that, under the conditions of this study, a single sauna session did not result in acute alterations of either cardiac or renal parameters. However, inadequate temperature control and lack of health education may expose users to potential risks, especially those with comorbidities. Further longitudinal and multicenter studies are required to assess the chronic effects of sauna baths.