We have reported that repeated sauna therapy improves impaired vascular endothelial function in a patient with coronary risk factors. We hypothesized that sauna therapy decreases urinary 8-epi-prostaglandin F_2α (PGF_2α) levels as a marker of oxidative stress and conducted a randomized, controlled study. Twenty-eight patients with at least one coronary risk factor were divided into a sauna group (n = 14) and non-sauna group (n = 14). Sauna therapy was performed with a 60°C far infrared-ray dry sauna for 15 minutes and then bed rest with a blanket for 30 minutes once a day for two weeks.
Systolic blood pressure and increased urinary 8-epi-PGF_2α levels in the sauna group were significantly lower than those in the non-sauna group at two weeks after admission (110 ± 15 mmHg vs 122 ± 13 mmHg, P < 0.05, 230 ± 67 pg/mg • creatinine vs 380 ± 101 pg/mg • creatinine, P < 0.0001, respectively). These results suggest that repeated sauna therapy may protect against oxidative stress, which leads to the prevention of atherosclerosis.