Wednesday, May 22, 2013

Blessed Are The Cold Rivers: Willpower For Chill Power

I had a great cold water swim today in a river. The river was high because of a wild, violent thunderstorm last night in Vermont, so I was actually able to swim against the current and stay in one place (my own "endless pool"). It was not just dive in and out. The temperature was 54 degrees Fahrenheit, 12 degrees Celsius, as measured by my trusty pool thermometer. 

I keep track because I'm an OCD measurer about such things. I'm a health hacker. It's a motivating factor–knowing the coldest water I've dived into, or the longest time spent in the water during certain times of year. 

It's also interesting to note the physical effects, which also of course comes from the scientific literature. A hint: they're really good.

Cold-water immersion (CWI) is a pretty hot topic in the fitness and therapeutic fields. For the sake of this discussion, CWI is swimming or diving into waters between 50-68 degrees F., or 10-20 C. And where the definition differs for certain effects, I will note that. Swimming in cool rivers, oceans, and pools has many beneficial effects:
  • It's anti-inflammatory; most aches and pains decline instantaneously, and the effect lasts for hours. If your knees are pounded and you don't want to dive in at the moment, just stand up to your knees in the water; you'll notice the benefit right away. CWI is great for spurring recovery from any hard exercise or soft-tissue injuries/problems–and it would be justified based only on this benefit.
  • It's a form of "hormesis" or good stress. I have a good chapter on this in Fitness For Geeks. There's evidence that CWI triggers an adaptation and hardens the body against infection by viruses and other physical maladies, as well as improves the body's antioxidant mechanisms.  Two studies found that regular winter swimmers had higher resting levels of certain biochemicals that are considered major antioxidants in the body. Recall that oxidative stress is at the center of the aging process as well as a number of major diseases such as cancer. Another study found that regular winter dips reduced fasting insulin levels substantially (high fasting insulin levels can be indicative of insulin resistance and inflammation in the body). Certainly, many cultures (the Scandinavians) and people swear by and demonstrate this notion that cold-water swimming has made them healthier in the longterm. The study pointed out that there is evidence that people doing regular cold-water immersions "have higher levels of antioxidants and that the cold shock response is attenuated with repeated immersions."
  • CWI stimulates brown adipose tissue (BAT), or brown fat (fat cells that contain more mitochondria and blood vessels, giving them a brownish hue compared with white fat) and cultivates the generation of BAT on the body. BAT is fat that is metabolically active (it generates heat and burns calories), while white adipose tissue (WAT), which a lot of us are carrying around too much of, is stored energy. If you're more metabolically active, it means you're overall healthier, from the standpoint of having a slightly higher resting metabolic rate, and moving glucose from the bloodstream and into muscles, thus keeping fasting blood glucose low, for example. From this study: "BAT is thermogenic, a property conferred by the presence of a unique protein, uncoupling protein 1 (UCP1). Located in the inner mitochondrial membrane, UCP1 uncouples mitochondrial respiration, releasing energy as heat. This unique property protects animals from hypothermia."
  • It's an appetite suppressant, and it lowers the resting heart rate (that may only be a temporary effect however lasting a few hours or more). The immediate effect of diving into cold water is to increase heart rate and blood pressure, which is an aspect of the Mammalian Diving Reflex. The latter mechanism is triggered when your face hits cold water. On the other hand, you are swimming, which is cardio, which lowers resting heart rate as a longterm training effect.
  • People tell me that they run for basic stress management; it's an "easy fix," as in the runner's high. CWI has the same effect on me, it induces relaxation and euphoria, and you're getting healthier to boot.
Chill Power

Cold thermogenesis
literally refers to the production of heat in the body in response to cold exposure (re: automatic muscle contractions or shivering)–but is sometimes referred to broadly as using cold for therapeutic purposes.  I plan to stick with it, for life. It's still hard for me, however, particularly when the air isn't hot enough to need the swim for relief (and I've swam when the air is 50 degrees F. this year), to muster the willpower to take a dive. Here are a few tips for overcoming those opening moments of hesistancy:

Have cold-swim buddies, to help solve the willpower and motivation issues concerning "taking the plunge." Keep a cold-swim diary. As you amass records of your swims, if you fail to get into the water, you'll disappoint yourself. Remember? You're a health hacker! You need data!

Have a nearby target to swim to. I have another place by the Mad River where there's a nice swim through gentle currents to a sunny rock, which gives me a "target." Then I get to lie on the warm rock and "chill" in the sunlight, followed by a dive back in and another cold swim sprint.

Such a contentful scene, with the sun shining on the river rapids and the warm rock.

Remember to obviously take part in CWI safely; diving into extremely cold waters (like 0 to <10 centigrade) can be dangerous for some participants. Although the effects lessen or attenuate the more you become adapted to CWI, cold shock typically involves an increase in heart rate, blood pressure, and oxygen consumption.

Various Science References:

"What is the biochemical and physiological rationale for using cold-water immersion in sports recovery?"

"Brown Adipose Tissue in Adult Humans: A Metabolic Renaissance.";

"Winter-swimming as a building-up body resistance factor inducing adaptive changes in the oxidant/antioxidant status.";

"Cold water immersion and recovery from strenuous exercise: a meta-analysis";

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