NEW YORK, Sep 30 (Reuters Health) -- Sitting in a sauna can silently aggravate heart problems in patients who experience chest pain while exercising, according to a report in the September issue of The American Journal of Medicine.
"These patients should be cautioned that there is a potential cardiac risk during sauna use," the researchers warn.
A team led by Dr. Nadia Giannetti of the Montreal Heart Institute in Quebec, Canada, reports that a study of 16 people with heart disease showed that those whose condition was aggravated by exercise were among the most likely to show a slight increase in heart rate while sauna bathing. In general, however, sitting in a sauna was well tolerated and most participants felt no pain or discomfort as a result.
The people in the new study had a heart condition called myocardial ischemia, which occurs when too little oxygen-rich blood reaches the heart. A heart attack occurs when the ischemia is prolonged and can lead to death or damage of the heart muscle.
"Although sauna bathing is generally considered to be safe, there have been reports of (fainting, heart attacks) and sudden death associated with its use," Giannetti and colleagues note. The new study found no such effects, but in certain people it may trigger silent or symptomless ischemia. The investigators speculate that increase in heart rate and levels of stress hormones that occur while sauna bathing may lead to problems with blood flow to the heart in patients with diseased coronary arteries.
To arrive at their findings, the researchers measured participants' heart rate and blood pressure during rest, while on a treadmill, and while sitting in a sauna. No patients felt faint or fainted while in the sauna.
Overall, participants' heart rate increased by about 2 beats per minute while sauna bathing. And there was a slight drop in their blood pressure levels, the authors found.
Compared with the rest period, there was more evidence of symptomless myocardial ischemia during the sauna bathing, the researchers note.
