Whole-body Cryotherapy and the Central Governor Theory

In response to US sprinter Justin Gatlin's unusual case of frost-bite in the build-up to the 2011 World Championships (see here), Gretchen Reynolds posted this entry on the increasingly-popular recovery technique known as Whole-body Cryotherapy (WBC).

The method works by essentially exposing the athlete to temperatures of -166 degrees F (-110 C), which is incidentally, colder than the surface of the moon. The exposure lasts only about 2-3 minutes and the recipient wears a mask, hat, gloves, and socks (Gaitlin's frost-bite occurred because his socks were wet from a workout).

While increasingly common, Reynolds points out in her post that the science behind cold therapy for recovery purposes is far from conclusive. In the few studies so far conducted on the subject, whole-body cryotherapy failed to lessen muscle damage compared to ordinary rest. One study did find fewer markers of inflammation in the blood of athletes who used WBC, but that does not mean a more rapid repair of the damaged muscles.

Despite the research, WBC and other less-technical cousins are growing in popularity, seemingly on the perception of recovery that cold-therapy seems to elicit. I've personally soaked my legs in cold water the day before races for almost four years, and found that doing so consistently gives the perception of greater "pop in the step," if you will. Having never examined the technique scientifically, it's hard to say if the added "pop" constitutes a true improvement in muscle recovery, or is merely perceived.

This raises an interesting question. If cold-therapies do not actually speed up the recovery process, why do so many people perceive that they do? Perhaps the cold has an effect on the brain, similar but opposite to the build-up of heat in the body during intense exercise. In the latter case, the sub-conscious brain appears to act to keep the intensely-exercising body from raising its temperature to a life-threatening level. This is one component of what Dr. Tim Noakes calls the "Central Governor Theory," which states in general terms that the intensity, duration, and type of exercise in which the body engages is governed by sub-conscious elements of the brain, so as to maintain a safe homeostasis.

Perhaps then, cold therapies act on the central governor in such a way that the body "feels" fresher than ordinary under similar conditions of muscle damage without cold-therapy. I've found that pouring cold water over my head during races in hot conditions temporarily lessens the perception of  effort, even though the pace remains the same. The effect is usually quite short, but it is noticeable. Similarly, it is well-documented that endurance events conducted in cooler temperatures yield faster times, maxing out somewhere in the neighborhood of 52-57 degrees F (one reason perhaps why this years' Boston Marathon yielded such fast times).

So we have a reasonably well-supported notion that heat is a major limiting factor in endurance sports. Perhaps it is possible that more localized sources of heat exist within damaged muscles, and that it is the cooling of these pockets of heat which produce the perception of recovery--without the actual muscle recovery-- that is often reported with WBC and other cooling techniques. Something to consider.