The idea that warmth can soothe not just the body but the mind stretches back through centuries of human culture. Across societies, heat rituals—from sweat lodges to bathhouses—have been embraced as ways to relieve psychic suffering. Yet when Eva Hilland, a cognitive neuroscientist at Oslo Metropolitan University, searched the scientific literature for evidence rigorous enough to support recommending heat as a genuine mental health intervention, she found surprisingly little.
"There are many knowledge gaps," Hilland acknowledged. Still, the fragments of evidence she did uncover struck her as promising enough to pursue. "So we just saw the potential," she said. Her conclusion points to a striking imbalance: while scientists understand a fair amount about how saunas and other forms of heat exposure challenge and condition the cardiovascular system, the question of how heat affects mental health remains largely unexplored territory.
That gap is becoming harder to ignore as sauna culture experiences a resurgence. Once associated primarily with Nordic traditions, sauna-going—often paired with cold plunges or winter swimming—is drawing a new generation of enthusiasts from the United States to Norway, a country where sauna bathing is deeply woven into daily life. The trend has moved beyond niche wellness circles and into the mainstream, with floating saunas, urban sauna clusters, and communal bathing spaces appearing in cities around the world.
Norway offers a vivid illustration of this cultural moment. In Oslo Harbor, beside the Opera House and the Munch Museum, sits Sukkerbiten, a pier lined with small saunas in an array of styles operated by the Oslo Sauna Association. The site has become a gathering place where locals and visitors alike cycle between intense heat and cold water, part of a ritual that devotees describe as both physically invigorating and mentally restorative.
The global spotlight on sauna culture was evident at the International Sauna Congress 2026 in Oslo, held in late September. Among the attendees was Tony Stepanow, a sauna enthusiast from Finland, photographed during the event. Such gatherings reflect how sauna practice has evolved from a private tradition into a subject of international interest—and, increasingly, a target of scientific inquiry.
Researchers are now asking a deceptively simple question: can deliberately heating the body treat conditions like depression? The premise is not as far-fetched as it might sound. Heat exposure triggers a cascade of physiological responses—increased blood flow, elevated heart rate, sweating, and the release of stress-related hormones—that mimic some effects of moderate exercise. Since exercise has documented benefits for mood and mental health, scientists suspect that heat may activate some of the same pathways.
But the mechanisms linking heat to mental well-being remain poorly mapped. Unlike the cardiovascular system, where decades of research have clarified how heat stress affects blood vessels and the heart, the brain's response to sauna bathing is far less understood. Hilland's literature review highlighted this disparity, finding few controlled studies rigorous enough to draw firm conclusions about heat as a treatment for depression or other psychiatric conditions.
Despite the gaps, the potential is significant enough that clinical trials are beginning to take shape. Researchers are moving cautiously, aware that promising anecdotes and cultural tradition are not substitutes for evidence. The emerging field sits at the intersection of neuroscience, physiology, and public health—disciplines that rarely converge around something as simple as sitting in a hot room.
The stakes are substantial. Depression affects hundreds of millions of people worldwide, and existing treatments—therapy, medication, and lifestyle interventions—do not work for everyone. If something as accessible as regular sauna bathing could offer even modest relief, the public health implications would be considerable. Heat therapy is generally low-cost, non-pharmaceutical, and can be incorporated into existing routines, particularly in cultures where sauna use is already common.
Skeptics, however, caution against overinterpretation. The placebo effect, the social aspects of communal bathing, and the relaxation that comes with any warm, quiet environment could all contribute to reported mood improvements. Separating those factors from the physiological effects of heat itself requires carefully designed trials with control groups and standardized protocols—studies that are only now getting underway.
Hilland's work reflects a broader shift in how scientists approach traditional practices. Rather than dismissing folk wisdom outright, researchers are subjecting long-held beliefs to empirical scrutiny. In some cases, the evidence vindicates tradition; in others, it refines it. For heat therapy and mental health, the verdict is still pending, but the fact that serious inquiry is happening at all marks a change.
The growing popularity of saunas may itself drive the research forward. As more people adopt heat exposure as a wellness practice, demand increases for evidence about what it actually does—and what it does not do. That demand, combined with advances in neuroscience and wearable health monitoring, could accelerate studies that were previously impractical or underfunded.
For now, the picture remains one of cautious optimism. The belief that heat can benefit the mind has deep roots across human societies, and modern science is only beginning to test whether those roots are grounded in biology or in culture. Hilland and her colleagues are among the first to systematically ask the question, and their early findings suggest the answer may be worth pursuing.
What emerges from the next few years of research could shape how clinicians think about non-pharmacological approaches to mental health—and whether a session in a floating sauna, followed by a plunge into cold water, might one day be prescribed alongside more conventional treatments. Until then, the science of heat and mental health remains a field defined as much by its open questions as by its early answers.
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