Given our focus on optimizing health and longevity, we look critically at what we can do to #biohack our bodies to improve health.
Something that comes up a lot, especially with our athletes, is cryotherapy. How does it work? Does it work? How and when do you do it? And for how long?
Can you even try it at home by taking a cold shower?
First the basics:
The cold triggers the production of the anti-inflammatory neurotransmitter, norepinephrine, a critical chemical in the body that helps to regulate attention and focus. It also reduces short term pain from injuries.
Norepinephrine also induces an overall anti-depressive and energetic effect by activating the sympathetic nervous system
So what's the science?
When skin is exposed to the low temperatures in a cryo chamber, the surface of the skin quickly reaches below freezing levels, which activates cold sensors. As a result, to protect the body and prevent hypothermia, the brain sends signals to maintain heat by constricting (or making smaller) blood vessels that supply muscles and other tissues. This leaves more blood flow going to the core, improving blood flow to your vital organs. It also reduces heat loss because smaller blood vessels release less heat. This vasoconstriction of the blood vessels leads to an immediate increase in blood pressure.
Another interesting change during cold exposure is with the blood composition – while under cold stress, the heart pumps blood that has more white blood cells, which fights infection and lower levels of several key pro-inflammatory chemicals.
How this affects the brain:
Cold exposure has been shown to improve depression, anxiety, and other mood disorders. The most important physiological effect cryo has on the brain is to increase norepinephrine, a process triggered by the cold receptors on the skin after extreme cold exposure. As mentioned earlier, norepinephrine helps to regulate mood, attention, focus, and even alleviate pain.
How this affects metabolism:
When exposed to extreme cold, we shiver. The purpose of shivering is aimed at maintaining core body temperatures. It creates heat to keep our cells functioning properly, but it’s not an efficient process.
So, after multiple exposures to cold temps, our cells shift to a more favorable thermogenesis and make more mitochondria, which create more energy and therefore heat. Norepinephrine helps make this shift happen.
This increase in mitochondria turns white fat tissue (which has very little mitochondria) into brown fat tissue (which burns energy to produce heat). Brown fat tissue is important for regulating body weight in healthy individuals and is also associated with metabolic rate. Increasing brown fat tissue limits weight gain and also helps to regulate blood glucose levels, which makes it a target organ for obesity control.
How this affects inflammation:
Our athletes especially enjoy the pain-reducing and anti-inflammatory effects of cold therapy. After all, when combatting sports injuries, sports medicine has long used ice baths and packs to fight inflammation and improve sore muscles. Inflammation gets a bad rap but it's actually a protective response to infection or injury which causes swelling, heat, redness and pain to either get rid of foreign invaders or regenerate injured tissue. So, it's a good thing, BUT when prolonged, it causes a lot of problems, like delayed-onset muscle soreness and diseases like diabetes, joint pain, rheumatoid arthritis. So, everything we can do to lower prolonged inflammation will improve both health span and life span/longevity.
Specifically, cryo can help increase levels of IL-10 - an anti-inflammatory compound, but lower levels of the pro-inflammatory compounds: IL-2, IL-8 and TNFα (tumor necrosis factor alpha).
How long to do it for?
A study looking at elite athletes concluded that 2 minutes at -211 F was optimal. However, no exact temperature that's optimal for every person, so 2-3 min at either -166 F/-211 F is fine. That being said, you'll also see benefit from cold showers too.
When to do it?
Studies have shown that before a workout, cryo can help increase flexibility, blood flow, and range of motion. It’s not recommended right after a workout, since the inflammation that ensues can help promote muscle regeneration, and you don’t want to halt this process. Doing cryo 24-72 hours later is the recommended time frame to reduce prolonged inflammation.
What do I do?
At the end of my showers, I turn the water to cold, starting at 30 sec, and working my way up to 3 minutes. It's easy, saves me the time and energy needed to run to a place with a cryotank.
Who is this contraindicated for?
Whole body cryo is contraindicated if you are pregnant, have severe hypertension, any history of a heart attack, arrhythmias, pacemakers, blood clots or vascular disease (poor circulation in a limb). Additionally, if you have any condition that would worsen from cold exposure, you should also avoid this biohack – these conditions include Raynaud’s, cryoglobulinemia, multiple myeloma, or cold urticaria.