The intense heat of a sauna isn’t for everyone. Because the human heart must work hard to send blood to the dilating capillaries, people with heart conditions should avoid saunas. Those with diabetes, multiple sclerosis, hypertension, auto-immune diseases, thyroid or kidney problems, or obesity should also check with their doctors, as should pregnant women in the first trimester.
A cool shower or swim afterwards increases blood pressure, so moderation is advised for people with a history of stroke or high blood pressure. During a sauna, your body can release up to a quart of water; avoid dehydration by drinking water or fruit juice before and after. Never deprive your body of water in an attempt to lose weight.
Replace minerals lost during saunas by eating foods rich in iron, zinc, magnesium, and copper such as vegetables and leafy greens.
