Sauna-induced myocardial ischemia in patients with coronary artery disease

Sauna bathing is a popular recreational activity that is generally considered to be safe. However, there have been case reports of adverse cardiac events. We sought to determine whether sauna use caused myocardial ischemia in patients with coronary artery disease.

Sixteen patients with proven coronary artery disease were submitted to three conditions (rest, exercise, and sauna bathing) with continuous electrocardiographic (ECG) monitoring and regular blood pressure measurements. During each condition, patients were injected with Tc-99 sestamibi followed by nuclear scintigraphic imaging. Perfusion defect scores were calculated in 15 patients.

Sauna bathing was well tolerated. There was a mean (+/- SD) increase in heart rate of 32% +/- 20% in the sauna (resting mean heart rate = 60 +/- 9 beats per minute vs sauna mean heart rate = 79 +/- 11 beats per minute, P <0.001) and a 13% +/- 6% drop in systolic blood pressure (resting mean systolic blood pressure = 142 +/- 14 mm Hg vs sauna mean systolic blood pressure = 123 +/- 15 mm Hg, P <0.001). There were no arrhythmias or ECG changes in the sauna. Compared with rest, there was significant ischemia during sauna bathing (average perfusion defect score at rest = -0.44 vs average sauna score = -0.93, P <0.001). The perfusion defect score in the sauna was worse than the resting score in 14 of the 15 patients. Sauna-associated perfusion defect scores were highly correlated with exercise-induced scores (R2 = 0.65, P <0.001).

In patients with stable coronary artery disease, sauna use is clinically well tolerated but is associated with scintigraphically demonstrated myocardial ischemia.