Baby, it’s cold outside. When the mercury drops, you still feel chilled after bundling up from head to toe and a hot bath just doesn’t cut it, do something good for your health and head for the heat. The Scandinavians got it right: Saunas can bring many health benefits, including treatment for heart disease, pain, mild depression and weight loss.

A study from Kagoshima University in Japan found that 15-minute sauna therapy sessions followed by 30 minutes wrapped in a blanket improved cardiac function and vascular endothelial cell function.

Endothelial cells line the inside of blood vessels and control their ability to expand and contract. Their functioning is impaired in people with diseases like hypertension, obesity and diabetes — all conditions tied to heart disease. But heat can help blood vessels relax, allowing the heart to pump blood better and prevent atherosclerosis, or hardening of the arteries.

The Japanese technique, called waon (WOW-n) therapy, involves a slightly cooler type of sauna therapy. Over a five-year period, the researchers found that two-thirds of patients who did not receive waon therapy were rehospitalized for heart failure or died of heart disease, compared with just one third of those who received the therapy.

They also found that heat therapy helped obese patients drop significant body fat after just two weeks. It can also alleviate high blood pressure and help treat chronic fatigue syndrome, pain, loss of appetite and mild depression.

Waon therapy is different from a regular trip to the sauna, but there are still benefits to be had by sitting in the steam. Here are a few tips to keep your sauna trip safe. Sit on a towel to prevent the spread of germs, and avoid taking a dip in cold water afterward if you have a heart condition. Also, make sure to bundle up before you head back into the chill!