Cold exposure as a potential mental health remedy has gained significant popularity in recent years, partly due to widespread endorsements on social media platforms, in wellness communities, and on high-profile podcasts.
Cold exposure is increasingly promoted on social media as a potential way to reduce symptoms of depression, anxiety, and other mental health challenges through its effects on physiologic arousal systems, including the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis.
Yet existing evidence supporting cold exposure as a mental health intervention has largely been derived from observational studies and case reports, which are constrained by methodological limitations, including small sample sizes, lack of appropriate controls, reliance on self-reported data, and inadequate adjustment for potential confounders.
With the growing popularity of cold exposure for mental wellbeing, it has become important for clinicians and researchers to gain sufficient knowledge about the existing evidence base for this practice.
This review article aimed to critically assess the reported mental health benefits of cold exposure and to describe the potential physiological mechanisms underlying these effects.
Mental health effects of cold exposure
Only three trials have been conducted to investigate the effect of passive cold exposure on acute mood changes in healthy individuals. These trials have reported associations between brief bouts of cold-water immersion and improved mood, increased vigor, decreased tension, increased positive affect, and reduced negative affect. The studies involved only 16–42 participants, used varied exposure protocols, and lacked active control conditions.
Three randomized controlled trials have also been conducted to examine cold-based interventions in clinical populations with depression or related affective disorders. In two trials, whole-body cryotherapy (exposure to extreme cold air) was associated with reductions in depressive symptoms when added to ongoing treatment, but the studies had important limitations and some benefits were not sustained.
The third trial compared cold showers with Wim Hof breathing, a form of rapid breathing popularized by cold-exposure advocate Wim Hof, against warm showers with slow breathing in 78 women with depressive symptoms. After three weeks, depression and anxiety symptoms fell by about 20–30% in both groups, with no significant differences between them. The study also combined cold showers with breathing exercises, so the effects of cold exposure could not be isolated.
Mechanisms driving mental health effects of cold exposure
Cold exposure triggers a complex physiological response, often referred to as the “cold shock” response. This response is characterized by rapid activation of the SNS and HPA axis to prepare the body for immediate physical demands.
The cold shock response is initiated by the activation of thermoreceptors in the skin that detect rapid temperature changes. These receptors send signals to central thermoregulatory nuclei in the hypothalamus, which in turn activates the SNS and triggers the release of the catecholamines epinephrine and norepinephrine. The hypothalamus simultaneously activates the HPA axis to increase cortisol secretion.
These hormonal changes trigger a series of adaptive responses, including peripheral vasoregulation, with vasoconstriction followed by superficial vasodilation, increased heart and respiratory rates, and heightened alertness, which collectively help preserve core body temperature and induce survival behaviors.
