Can passive heat- or cold-treatment mitigate depression? A review of physiological adaptations and clinical evidence

Physical and mental health are tightly coupled. With a rising prevalence of the major mood disorders, recent years have seen a growing interest in the potential therapeutic value of lifestyle practises such as exercise and passive heat- or cold-treatment (e.g. sauna and ice baths). While the beneficial effects of exercise on mental health are now well documented, the potential benefits of heat- and cold therapy are less studied. Similarly to exercise, passive heat- and cold exposure may induce physiological responses which counteract the pathophysiological underpinnings of mood disorders such as depression and anxiety. Thus, passive heat- or cold treatment could complement exercise, or be a viable alternative for individuals hindered from doing exercise due to injuries or disability. Here, we first review physiological adaptations to passive heat- or cold treatment in the context of hypothesis for the biological pathogenesis of depression. Next, we review clinical interventions investigating effects of passive heat- or cold treatment on depressive disorder. Finally, we end with a discussion of future directions.