I recently came back from a trip where I did a mini Spartan-style obstacle course. It was definitely a challenge physically and left me with a decent amount of aches and pains. After, I hopped into a 33°F cold plunge tub for two minutes, and when I got out I felt amazing. Don’t get me wrong, I was shivering and numb, but I pretty quickly felt that my pain may be gone. I jumped in a hot tub for about ten minutes, and when I got out, indeed, my pain was gone.
So, what happened physiologically that impacted my sore muscles and hip pain so quickly?
Well, I had taken four BrocElites and six CurcElites. But in terms of the cold water exposure, there are quite a few things going on, especially since I did Wim Hof breathing before I jumped into the cold water. I’m simply going to highlight the increase in norepinephrine and the improvement in inflammatory markers.
Norepinephrine is a hormone and a neurotransmitter that is known in Europe as noradrenaline. It functions to mobilize the brain and the body into action and is responsible for the “fight-or-flight” response we have during moments of perceived danger.
In the brain, norepinephrine increases alertness, and focuses one’s attention. In the rest of the body, norepinephrine increases heart rate, activates thermogenesis (the production of heat), constricts blood vessels, and increases immune function.
A recent study using a nitrogen gas to cool the body showed that a 20 second cold exposure can increase norepinephrine 200-300%. The cold plunge is among the few ways to increase norepinephrine therapeutically. Cold exposure from water or nitrogen gas is known as cryotherapy.
The cold plunge can also help exercise induced inflammation.
One study out of Milan, Italy looked at athletes who did both resistance and aerobic training followed by a two-minute cryotherapy for five days and how it improved their inflammatory markers. The results showed an increase in IL-10, an anti-inflammatory marker, and a decrease in IL-2 and IL-8 pro-inflammatory markers. Markers of muscle damage, such as lactate dehydrogenase, also decreased. Another study showed a drop in pro-inflammatory cytokine TNF-alpha with cold therapy.