Ask the doctors: Heat therapy may alleviate depression, study suggests

Dear Doctors: I saw there’s a new study saying that heat therapy can be good for depression. Do you know if this is true? My husband’s family is from Norway, and they swear that using their sauna helps them to not get depressed during the long and dark winters they have there.

Dear Reader: Interest in using external temperature to improve mental health dates back millennia. Early Egyptian texts cite practices that mirror modern-day cryotherapy, which is the use of very cold temperatures. On the flip side, the ancient Greeks believed warm baths to have a therapeutic effect on mood. And with imagery such as “hot-headed,” “cold-hearted” or “warm-spirited,” the connection between temperature and emotion is embedded in our everyday language.

Now, a small study from researchers at the University of California, San Francisco, sheds new light on the concept. The findings suggest whole-body heat treatment, similar to what one experiences in a sauna, may benefit people being treated for depression. With depression a widespread – and often debilitating – disorder, it’s not surprising that the study results made their way into the news cycle.

A recent Gallup poll found that close to one-third of adults in the U.S. have been diagnosed with depression in their lifetime. Although medications are available, they can be slow to take effect, may offer only partial relief and can have challenging side effects.

The study you are asking about, published last spring in the International Journal of Hyperthermia, evaluated the use of whole-body hyperthermia treatment in 16 adults diagnosed with major depression. During the two-month study, the participants underwent biweekly sessions of whole-body heat therapy. They also participated in weekly sessions of a blend of behavioral and cognitive therapy. The heat therapy took place in infrared sauna domes that covered the participants’ bodies up the neck, with the head left free. Participants remained in the heated domes until their core body temperature had reached 101.3 degrees.

At the end of eight weeks, 11 of the 12 people who completed the study no longer met the diagnostic criteria for major depressive disorder. This was ascertained through standardized mental health questionnaires and self-reported data. The decrease in the symptoms of depression was more pronounced than would be expected from behavioral and cognitive therapy alone. These findings mirror those of previous research, which has also seen positive outcomes in the use of hyperthermia to treat depression.

As for whether hyperthermia may be effective in treating major depressive disorder, the answers are not yet clear. It has been observed that people living with depression often have a higher body temperature than those who do not have the disorder. When symptoms of depression ease, the person’s elevated body temperature returns to a more normal range. In discussing this study, the researchers theorized that triggering the body’s cooling systems during the sessions of hyperthermia led to a continued lowering of body temperature after the treatment had ended, which in turn led to an easing of symptoms. Because this was a small participant pool, the researchers are now planning a new and larger study.

Send your questions to askthedoctors@mednet.ucla.edu.