Cold Exposure

On the back of the sauna and heat exposure blog last week, we have to follow it up with cold exposure.

Once again Dr Rhonda Patrick, as well as Dr Andrew Huberman and Susanna Soeberg who wrote the book Winter Swimming: The Nordic Way Towards a Healthier and Happier Life, have been extensively covering this topic for a long while now.

In modern times, cold exposure is used primarily to reduce muscle soreness and promote muscle recovery after physical activity. However, regular cold exposure may also improve glucose and lipid metabolism, decrease inflammation, enhance immune function, and improve cognitive performance.

The beneficial effects of cold exposure may be due to hormesis, a favorable biological response to a mild stressor. Hormesis triggers protective mechanisms that provide protection from future, more harmful stressors.

Exposure to cold temperatures induces a range of acute physiological responses, collectively referred to as the cold shock response. The goal of the cold shock response is to reduce heat loss and increase heat production. With repeated exposure, the body becomes habituated to cold, diminishing the cold shock response.

General health effects associated with cold exposure:

  • Metabolic health

  • Immune function

  • Antioxidant enzyme activation

  • Inflammation

  • Arthritis

  • Exercise-associated inflammation

  • Microbiome

  • Mood and cognition

  • Brain aging

  • Cold exposure exerts variable effects with exercise

Cold exposure safety concerns:

Cold exposure poses some health risks, especially in unsupervised or uncontrolled conditions. The most common risk associated with cold exposure is hypothermia, a condition in which a person's core body temperature drops below 35°.

Symptoms of hypothermia include rapid breathing, shivering, pale skin, confusion, and drowsiness. If hypothermia occurs in a large body of water such as a lake or ocean, it can impair respiration and may lead to drowning.

Other risks of cold exposure include afterdrop and frostbite. Afterdrop refers to a drop in core body temperature after exiting cold water and is common among open-water swimmers. Immediately after exiting cold water, the cooler blood from peripheral tissue returns to the central circulation, inducing a drop in core body temperature and subsequent hypothermia.

Frostbite occurs when the skin freezes. It is common on peripheral tissues such as the fingers, toes, nose, ears, cheeks, and chin. Exposing skin to air temperatures less than -12.2°C can cause frostbite. As a result, a person can develop frostbite in 30 minutes or less when the wind chill is -26°C or lower.

In one of his podcasts Dr Huberman mentions the best way to warm the body is to heat the palms of the hands as well as the bottom of the feet.


A growing body of evidence demonstrates that cold exposure may serve as a hormetic stressor that switches on a host of protective mechanisms that reduce inflammation, activate antioxidant enzymes, improve athletic performance and promote recovery, and boost the immune system to protect against age-related diseases.

Post-exercise cold water immersion may also increase PGC-1 alpha, a protein that promotes mitochondrial biogenesis. Cold exposure activates brown fat, a type of adipose tissue that is associated with a lower prevalence of cardiometabolic diseases and may be a promising therapy for obesity and obesity-related disorders.

Early studies in mice suggest that cold exposure can alter the composition and activity of the gut microbiome to improve energy metabolism and support thermogenesis. While more direct evidence is needed, cold exposure may even serve as a strategy for the treatment of cognitive and mood disorders.

Although cold exposure for the purposes of health is an ancient practice, it remains a promising beneficial lifestyle behavior that should be conducted with caution and supervision.

You can access the full article by Dr Rhonda Patrick by clicking this link:

I myself don't have access to a cold plunge so cold showers is what I do, I do my best to do 5 x 3 minute sessions every week after 20 minutes in the sauna, which is what Susanna Soeberg advised on the the Dr Huberman podcast.