For over a hundred years Finnish sauna has been documented as a physiotherapeutic method in respiratory diseases. Physiological changes of ventilation remain small (about 10%) in the sauna. Heat load, sauna air and sympathetic stimulation generally do not cause problems to the lungs. Electron microscopic studies have not shown irreversible damages to the airway epithelium. Sauna takers should avoid bathing during acute respiratory infections. Sympathomimetic drugs may provoke tachycardia and arrhythmias in the sauna.