COLD AND HEAT EXPOSURE
What’s all the fuss?
Exposing our bodies to extreme temperatures has never been more popular with the increase of recovery centres, ice beaths and saunas. Let’s dig into the benefits of both cold and heat exposure.
Cold Exposure
Immunity - When we are exposed to the cold (cold showers/ice baths), our bodies release adrenaline from our kidneys. When we have an adrenaline spike throughout the body, this prompts an increase in natural killer cell activity. Natural killer cells are a crucial part of our immune system which when stimulated, helps us fight infection and eliminate toxins from the body.
Stress management - When we release adrenaline from the brain, we can train ourselves to control our thoughts and feelings. Remaining calm from cold exposure limits adrenaline release. Cold exposure is great for helping raise your stress threshold and can help you better tolerate a higher degree of daily stress.
Focus and alertness - There is now evidence to suggest that dopamine levels can remain elevated for up to 7 hours after cold exposure! Dopamine is important for focus, motivation and alertness. Cold exposure at the beginning of the day can be a great way to tackle a busy workday and to reduce sluggishness, fatigue and brain fog.
Heat Exposure
Improved endurance - Our core body temperature increases when we exercise, which is beneficial to improve our cardiovascular fitness. To achieve this rise in our core body temperature without exercising we can expose our body to heat through devices such as saunas. Sauna use increases our heart rate, blood flow and oxygenation through the body, this adaptation can help improve our cardiovascular activity.
Building muscle - When we exercise, the proteins in our muscles break down, After this break down, our bodies repair, recover and grow muscle. Your muscles, even if you don’t currently exercise, are always performing a balancing act between producing muscle and breaking down existing muscle. Heat exposure has been shown to reduce the amount of muscle breaking down, resulting in an overall net increase in muscle growth. It does this through increased production of heat shock proteins (also shown to improve longevity), growth hormones and improved insulin sensitivity.
Sleep - Our core body temperature fluctuates by 1-3 degrees throughout the day in line with our circadian rhythm (sleep-wake cycle). 3 hours before we wake up, our core body temperature starts to rise and 3 hours before our regular bedtime, our core body temperature starts to dip (also known as our temperature minimum and maximum). Heat exposure in the form of a sauna, shower or bath can be great before bed as our body’s response is to cool down.
References
Sauna use as a lifestyle practice to extend healthspan - ScienceDirect
Exposure Guide | SH//FT (shiftadapt.com)
Using Deliberate Cold Exposure for Health and Performance - Huberman Lab
Srámek, P., Simecková, M., Janský, L., Savlíková, J., & Vybíral, S. (2000). Human physiological responses to immersion into water of different temperatures. European journal of applied physiology, 81(5), 436–442. https://doi.org/10.1007/s004210050065