Cold Exposure, Inflammation, and Immune Function
We’ve all experienced the flu, twisted an ankle, and gotten a bruise before. Across all of these experiences, and more, humans share the common feeling of an inflammation response from our body.
The purpose of an inflammatory response is to mitigate the initial cause of injury, clear out dead cells and damaged tissue, and to initiate tissue repair. However, when the process doesn’t go as planned—think fever—it gets interesting.
Case in point, inflammation has been identified as the key driver of the aging process. In fact, it’s often associated with most age-related diseases.
Inflammation is, so to speak, a double edged sword in a lot of ways. Cold immersion therapies, like whole body cryotherapy, have been shown to have a direct influence on inflammation.
Norepinephrine Reduces Inflammation
Remember when we talked about norepinephrine in depth?
No? You may like a quick look at our blog "Your Brain Loves The Cold" to get caught up.
Initially, we wrote about norepinephrine’s role as a neurotransmitter. However, norepinephrine has many other roles outside of that.
It’s possible that some pain reducing effects of whole-body cryotherapy may be related to an increase in norepinephrine levels, since inflammation itself causes pain. In fact, spinal injections of compounds that induce norepinephrine release have been shown to reduce pain in both human and animal studies.
When you put your body through cold stress, norepinephrine increases. One of its purposes is in reducing inflammation by inhibiting the pathway for TNF-alpha, a potent inflammatory molecule.
Excess TNF-alpha is associated with almost every human disease, ranging from type-2 diabetes to inflammatory bowel disease and cancer. Norepinephrine reduces TNF-alpha, but it also decreases levels of other chemicals like MIP-1α, which is produced by immune cells and potentially plays a role in rheumatoid arthritis.
Arthritis and Cold Immersion Therapy
When you reduce inflammation, for the most part, it’s usually a good thing. This is especially relevant to arthritis. In a randomized, controlled trial, patients with arthritis underwent whole-body cryotherapy and saw a significant reduction in pain.
Their therapy was structured to include:
· Temperatures of -166 degrees F
· A time of 2 to 3 minutes
· A frequency of 3 treatments a week
· A run time of 1 full week
Cold immersion therapy goes well beyond just arthritis though. It has been shown to have an effect on your general immune function.
Cold Immersion and Your Immune System
Like inflammation, the immune system also plays a role in the aging process. Generally, aging is associated with a reduction in immune cells and non-functional immune cells. What’s interesting is that super-centenarians usually have a healthy, biological stock of immune cells.
Cold immersion therapies seem to increase certain types of immune cells. For example, long term, cold-water immersion (3 times a week for 6 weeks) in healthy males was shown to increase lymphocyte numbers.
This runs parallel to the fact that habitual winter swimmers have higher numbers of white blood cells. Additionally, recent research demonstrates that cold exposure in a climatic chamber at 41 degrees F increased white blood cell numbers. Specifically, it increased cytotoxic T lymphocytes: specialized types of immune cells that kill cancer cells.
Further, males exposed to a cold room for 30 minutes, and decreased their core body temperature to 0.45 degrees C (find F), saw an increase in natural killer T cell numbers and activity. These natural T killer cells are yet another type of immune cell that kill viruses and tumor cells.
