Cold - what is it good for? Lots, we are discovering. Immune response, inflammation, fat burning, anti-oxidation,
Norepinephrine (vigilance, focus, attention and mood)↑
Cytokines (inflammatory markers) ↓
Good stress = “hormetic”; a short-term stressor that has benefits
Prophylactically protective for TBI
Cold shock proteins such as RBM3 rebuild neurons
Norepinephrine, induced by cold, reduces inflammation by decreasing tumor necrosis factor alpha (TNF-alpha), implicated in almost every human disease from Type 2 diabetes to inflammatory bowel disease and cancer.
Cold appears to increase lymphocyte numbers. This is in line with the fact that habitual winter swimmers have higher number of white blood cells compared to non-habitual winter swimmers.
Boosts metabolism (300% for 1 hr at 68 degrees)
Nonshivering thermogenesis (brown fat activation)- responsible for the “fat burning” effect of cold exposure once the body has adapted to cold exposure.
Amount of brown fat is inversely correlated to percent body fat.
The greater the release of norepinephrine that we can induce from cold, the more brown fat produced.
Cold activates very potent genetic antioxidant systems which are exponentially more powerful than supplemental antioxidants (glutathione reductase, and superoxide dismutase).
Cold is a tool, so use it wisely. Muscle growth is an inflammatory process. So, if you are trying to build muscle mass, wait on the ice bath for at least an hour of after working out.
Even more esoteric: Cold exposure activates a gene called PGC1α, which makes more mitochondria in the muscle. Mitochondria are your cell’s engines; they produce energy and heat. More mitochondria per muscle cell directly translates to aerobic capacity, and a single 15 minute exposure to cold water (50°F) following high intensity running, increases PGC1α in muscle tissue.
So, re cold:
Brown fat raises insulin sensitivity, a critical health marker
The body will adapt to function; Give the body a reason to become good at something
BP drops; HR drops; circulation improves
After ice bath, sit in meditation; This is where you can choose to generate heat from brown fat vs shivering; Shivering is also a response to cold, but less controlled, less efficient
Trust that the body gives you what you need, then divert it to what you want
Safety: Afterdrop - Get out if shivering, erratic breathing; before you feel cold; Focus after exposure.
Increases norepinephrine up to 5-fold in the brain. Temperature and duration needed to do this is 40°F (4.4°C) for 20 seconds
Norepinephrine has an effect on mood, increases vigilance, focus, and attention (especially over a prolonged period).
Cold exposure increases cold shock proteins, including one in brain that repairs damaged synapses and in muscle prevents atrophy.
Cold-induced norepinephrine lowers inflammation and pain by decreasing levels of inflammatory mediators.
Chronic cold shock may increase immune cell numbers including a type of immune cell that kills cancer cells.
Cold exposure increases metabolic rate, number of mitochondria, and burning of fat.