Q. My neighbor just built a sauna. I’ve heard that sitting in a sauna is good for my high blood pressure. Should I take my neighbor up on his offer to use his sauna whenever I feel like it?
A. There have been a few studies that look at saunas as therapy for high blood pressure. First, though, ask your neighbor if his sauna uses radiant heat or infrared heat. Radiant heat saunas are usually wood-paneled rooms using radiant heaters that put out dry or heat or wet steam. However, the two best studies I know of regarding saunas for lowering high blood pressure use infrared saunas; these rooms are warmed by infrared heat lamps.
A study reported in the German cardiology journal Z Kardiol in 1994 (researcher C. Siewert) looked at 46 men with high blood pressure. Participants sat in an infra red sauna twice a week for three months. The men who used sauna had a significant drop in blood pressure. Before using the sauna, the average blood pressure reading was 156 over 101 mmHg. After sauna time, the average blood pressure reading was 143 over 92 mmHg. This is similar to the effect people see by talking medication that lowers blood pressure.
A study published in the Japanese Heart Journal in 2004 used far infrared heated saunas to treat high blood pressure. (Infrared heat lamps are divided into three bands: near, mid or far.) Participants had at least one risk factor for heart disease. People sat in saunas heated to 140 degrees Fahrenheit for 15 minutes daily for two weeks, and they followed up sauna time with a 30-minute rest period. The participants that used the sauna were able to lower their systolic blood pressure; this is the top number in the blood pressure reading. The people who didn’t use the sauna had an average systolic reading of 122 mmHg while the people using the sauna had an average reading of 110 mmHg.
Why might saunas help lower blood pressure? Our bodies use nitric oxide to control the size of our blood vessels, and we release nitric oxide when we sit in saunas. Secondly, sauna time is relaxing, and our mental states are an important component of our blood pressure readings. Our bodies also respond to sauna time by increasing cardiac output, meaning the blood flow increases, helping circulation, bringing more oxygen to our muscles and increasing our metabolic rate. This effect is like the benefit we garner while participating in low-grade exercise. Obviously, relaxing in a sauna isn’t a replacement for exercise, but it might be another mechanism to help people lower their blood pressure.