Some health benefits of cold exposure
- Charmaine Cunningham
- May 28
- 4 min read
‘There is nothing – no medication, no other form of exercise – that can shock you out of your head and back into your body like cold water can.’ - Susana Søberg - Winter Swimming
It is hard to ignore the health benefits of regular cold exposure. In recent years cold plunging has become very popular, as is evident even in our group that started out as three people at 7am with no one else in the water. Now, during summer mornings, the group is often quite large with many doing so for the perceived health benefits.
This blog on cold exposure is by no means supposed to be exhaustive, and I’m only mentioning a few things I find interesting.
To understand the benefits a fundamental concept in evolutionary theory known as hormesis is helpful. Hormesis derives from the ancient Greek root word hormáein meaning ‘to excite’. (This is also the root word for hormone in case you were wondering). Hormesis refers to a relationship with an environmental factor whereby a low exposure to it has beneficial effects, whilst a high-dose or high-exposure will have an inhibitory effect or even cause toxicity.
For example, people die from hypothermia, so too much cold exposure is clearly toxic, whereas small doses have beneficial benefits.
During ‘controlled’ cold-water swimming or cold exposure, the cold activates the nervous system which triggers a temporary stress response. With frequent exposure the stress response results in the body adapting to the stressor (cold), resulting in better functioning, resilience and other positive effects on the body. Most benefits relate to hormones including endorphins (a swimmer’s high is certainly sounds more fun than a runner’s high!) dopamine, cortisol and catecholamines.
Health benefits include, but are not limited to
· Concentration and cognitive function. Several studies suggest that cold exposure may enhance focus and improve mental acuity for several hours after exposure. It is likely due to the nervous system response releasing norepinephrine. Norepinephrine plays a key role in enhancing alertness, focus, and cognitive function as it prepares the body for a ‘fight or flight’ response.
· Improve cardiovascular health. It has been proposed that frequent cold exposure can reduce resting heart rate and lower blood pressure. This is again related to the catecholamine release causing peripheral blood vessels to constrict and redirecting blood flow to the vital organs (heart, lungs, kidneys and brain) which means more oxygen and nutrients are supplied to these areas.
· Mental health and stress benefits. The endorphins boost mood and energy. It is further argued that the ability and willpower to do something that is not pleasant e.g. going into or sometimes even staying in the cold water equips us to be better deal with ‘real’ life stressors outside of the water.
· Improved metabolism. Cold exposure induces shivering and activates brown fat (brown adipose tissue) to burn calories to generate heat, increasing the body’s energy expenditure. Even though white fat (white adipose tissue) is the primary fat in the body, brown fat is more metabolically active. Some studies suggest that brown fat activation may improve insulin sensitivity, which implies that the body is more responsive to insulin and thus more effective in utilizing glucose for energy.
· Improved immune system activity. Studies suggest cold exposure may result in the body producing more white blood cells, which fights disease, and it is further proposed that the vasoconstriction in the lymphatic system helps lymph fluid to move faster, removing waste products from the body faster.
· Biological gender matters. Cold water impacts men and women in differently, and especially in women, factors such as phase of menstrual cycle and menopause may impact on tolerance and even the health benefits.
Protocols
There is an abundance of ‘how to’ resources about cold water exposure and I’m only sharing those I feel I can follow. However, as a full-time researcher (not on this topic though), I’m inclined to follow the work of researchers or scientists with academic credentials, and I’ll refer to Andrew Huberman and Susana Søberg.
What counts as cold exposure, for how long and when? It is suggested to do 11 minutes of cold exposure per week, spread over 2-4 sessions early in the day in 10-15 degrees Celsius water. Earlier in the day allows your body to warm up afterwards, and that it could disturb your sleep if it is done too late in the day.
The Søberg principle is to end your cold exposure without external rewarming. Let your body reheat naturally, allowing the body to restore its balance, rather than immediately taking a warm shower or sauna. This will increase the benefits, especially the metabolic ones.
Not every day. Another principle is to not do it every day of the week - a few times a week will maximise the benefits without putting your body into a state of chronic stress. (This links back to the concept of hormesis)
Do not extend the time in the water. The release of hormones especially dopamine and endorphins could lead you to overestimate tolerance levels.
Do not do breath work in the water, especially not cyclic hyperventilation, as it could be unsafe.
Finally, especially for those wearing swim caps 😊 You only need to submerge your body up to the neck, including your feet and hands. (I’m not quite sure how you would enter the ocean without your feet getting wet, and I assume it is more applicable to the plunge pool people out there!
Cold exposure is an example of hormesis which is a biological process where exposure to mild stressed can induce a beneficial adaptation in the body that may lead to long-term benefits. A lot of research is being done on the topic, I’m looking forward on reading and sharing more about why we do it, or should I say why it feels so good 😊
Some resources
Andrew Huberman – has spoken about cold exposure on his podcast a few times, and I’m adding a link to some https://www.hubermanlab.com/topics/cold-plunges-and-deliberate-cooling
Susana Søberg https://soeberginstitute.com/pages/about
Differences in men versus women https://soeberginstitute.com/blogs/journal/men-vs-women-in-cold-water-immersion-what-science-reveals
Women specific – on menstrual cycle, menopause and cold water
Hormesis
Susana Søberg wrote a book on the topic called Winter Swimming -https://exclusivebooks.co.za/products/9781529417463
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