Can Heat Therapy Help Depression? What Emerging Research on Saunas and Whole-Body Heating Suggests

On a crisp morning in Oslo’s harbor, people step into small floating saunas lined up along the pier. Some are there for the ritual - the quiet, the heat, the plunge into cold water afterward. Others are part of something more deliberate. Cognitive neuroscientist Eva Hilland at Oslo Metropolitan University is recruiting participants for a trial that pairs regular sauna sessions with simple mental-health habits. The goal is to measure effects on stress, sleep, and well-being in a setting that already draws people seeking relief.

This work sits at the intersection of an old practice and new questions. Cultures around the world have long used heat - saunas, baths, sweat lodges - for both body and mind. Modern wellness trends have revived interest, and surveys of sauna users repeatedly list mood, stress reduction, and better sleep among the reasons people return. Scientists understand the cardiovascular effects of heat reasonably well. The mental-health side has been thinner on controlled evidence, though that is starting to change.

A landmark trial that raised core temperature

One of the clearer early signals came from a randomised, double-blind trial published in JAMA Psychiatry in 2016, led by researchers including Charles Raison and Christopher Lowry. About 30 people with major depression received either a single session of whole-body infrared heating designed to raise core temperature to roughly 38.5°C (101°F) or a sham treatment. Within a week, a majority of those in the active group showed at least a 50% reduction in symptoms, and the difference relative to the sham group remained detectable at six weeks. Side effects were generally mild.

Lowry, an integrative physiologist at the University of Colorado Boulder, has studied mechanisms that could help explain such effects. Heat sensed by the skin signals the brain to initiate cooling. Those pathways overlap with circuits involved in mood and reward. Heat also appears to trigger an anti-inflammatory response and, in animal work, activates certain serotonin-producing neurons linked to stress resilience. The picture is incomplete, but the physiological stimulus is real.

People with depression often “run hot”

Ashley Mason, a clinical psychologist at UCSF who studies mood, sleep, and thermoregulation, was drawn to this area partly by the 2016 findings and by a consistent observation in the literature: people with depression tend to have higher body temperatures and less daily fluctuation. Her group’s analysis of wearable data from nearly 20,000 people found that higher symptom severity tracked with elevated skin temperature and reduced nighttime cooling, even after accounting for weather and medical factors.

Heating someone further can seem counterintuitive, yet Mason describes it as a kind of thermoregulatory workout. After the heat exposure ends, body temperature drops and stays lower for a longer period than the time spent heating. The rebound cooling may last days or longer; the exact duration is still being clarified. Older studies have also shown that successful antidepressant treatment can improve thermoregulation, suggesting the relationship runs in both directions.

In small pilot trials, Mason’s team combined four sessions of infrared whole-body hyperthermia with eight weeks of cognitive behavioral therapy. Most participants no longer met criteria for major depression by the end. These studies were not powered as definitive efficacy trials, and one sham condition proved imperfect, but they established feasibility and informed larger work now underway at UCSF and other sites. Mason is careful about the stage of the research: “Heat does seem to be a promising therapy, but we’re very much at the beginning.”

What this does and does not mean for people living with depression

If you have struggled with depression - especially if medications or therapy alone have brought only partial relief - the idea of a non-drug approach that works through the body’s own temperature regulation can feel worth exploring. The communal, low-tech nature of sauna culture may also matter. Time away from screens, mild social connection, and the simple physical release of sweating can contribute independently of any specific heat effect. Hilland’s Oslo trial is designed partly to capture that real-world combination.

At the same time, the evidence base remains early. Sample sizes in the controlled human trials have been small. Protocols differ (infrared devices that raise core temperature versus traditional saunas). Not everyone can safely use intense heat: people with certain cardiovascular conditions, who are pregnant, or who take medications that affect heat tolerance need individualised medical guidance. Hydration, session length, and recovery matter. Self-experimentation is not a substitute for evidence-based care.

Mason has said that for people who have tried many treatments, heat therapy may eventually earn “a seat at the table” alongside options like exercise. That framing is useful. It positions heat as a potential adjunct rather than a replacement, and it underscores the need for the larger, rigorously controlled trials that researchers are now pursuing.

A grounded place for curiosity

The practice of using heat for mental relief is not new. The systematic attempt to understand how and for whom it works is. Ongoing studies in Oslo, at UCSF, and elsewhere are testing whether repeated sessions, alone or combined with behavioral approaches, produce durable benefits beyond what expectancy or the surrounding ritual can explain. Until those results arrive, the most honest summary is that heat is a plausible physiological stimulus with preliminary antidepressant signals and a plausible mechanism involving temperature regulation, inflammation, and neural pathways, but it is not yet an established treatment.

If you are already drawn to the sauna for how it makes you feel, the emerging research offers a reason to pay attention rather than a guarantee. If depression has narrowed your options, it may be worth discussing with your doctor who can weigh the limited data against your specific health picture. The science is still catching up to the practice. For people living with depression, any carefully studied additional tool is worth watching closely.