You may have heard of cryotherapy, the practice of exposing athletes to extremely low temperatures to improve recovery. If you google it, the outputs are countless from ‘Wales indebted to cryotherapy for Warburton’s return’ to ‘Phoenix Suns freeze players’ or ‘Dallas Mavs disclose their cryotherapy secret’. Let’s cut this to the chase: believe the hype?
First things first, I started sifting the literature a bit biased; scepticism was infused in my opinion on the matter. While my doubts still stand, I must admit some research suggested me this topic deserves some attention and, mostly, more tailored studies. I’ll try not to convey my negative mind set, I’ll try my best.
Why should the exposure to cold temperature improve recovery, meaning force recovery and feeling of pain after an intense workout session?
Cold should constrict muscle blood vessels, reducing the inflammatory state and the formation of oedema which comes from muscle damage, naturally occurring after intense training with a high volume of eccentric contractions. This damage consists in the usual aching pain sensation you feel up to a few days after that heavy training day when you pushed far too hard. With the mechanism described cold should limit the inflammatory state which brings further damage, reducing muscle breakdown and pain. The same principle when you put ice on a twisted ankle.
Besides, some authors suggest that cold could also stimulate a soothing endorphin release, improving anti-oxidant protection, decrease pro-inflammatory cytokines while increasing anti-ones (See this previous post).
Even more interesting, cold exposure could increase sympathetic firing and raise noradrenalin levels, which in turn could affect creatine kinase (CK) metabolism. CK is a marker of muscle damage and its cold-prompted decrease might suggest a lowered muscle breakdown.
So my doubts?
Rises from the fact that those inflammatory processes are also those which drive muscle repair and growth, so even in the case cold exposure could reduce muscle inflammation, would we want it? (Check this post on anti-oxidants)
I focused the inquest on those studies using the most fashionable Whole body cryotherapy system (WBC), the one Steve Nash and Miroslav Klose like so much. You enter in a chamber in minimal clothing, where you familiarize with a -60 °C for some 30 second, then into a -110 for 3 minutes. Sure it’ll be refreshing.
- Costello et al study: cold exposure 24h after an eccentric training protocol, no change in strength recovery or pain when compared to passive (doing nothing) recovery. Also, proprioception was not altered, suggesting that WBC does not compromise kinaesthetic sense which could lead to higher injury chance.
On the contrary, two other studies found WBC beneficial for faster recovery. The most interesting data is a difference in the selection of subjects and protocol. While on the Costello’s paper they used ordinary guys, on the WBC-positive ones well-trained if not pro players were picked and WBC was repeated in multiple sessions.
- Hausswirth: WBC at 1, 24 and 48 hours post training, strength recovery already evident only one hour after the effort when using WBC and better than passive recovery at 24 and 48h.
- Banfi compared the inflammatory state of Italian Rugby national players in a hectic training period on two consecutive Monday mornings before and after 5 WBC sessions on alternate days. Not only pro-inflammatory cytokines were reduced and anti-inflammatory enhanced, but the muscle breakdown marker CK was decreased.
Could it be that a systematic WBC protocol could reduce the inflammatory state and improve strength and soreness recovery on highly trained subjects?
Indeed aptness to muscle trauma can be ‘trained’ (the repeated bout effect), as you notice when you start the first workouts after a long summer break. The first workout makes you cry for days, while the same workout a few weeks later could pass unnoticed and give no pain at all. Higher trained athletes could establish an interaction between the repeated bout effect and cryotherapy, making it effective in quickening recovery.
Final word, athletes are renown superstitious. The psychological effect of a recovery habit that resembles sci-fi chambers and the word of mouth spread by top guns may do the work.
There’s definitely a need of new studies simulating more ‘real-world’ conditions and taking account of various athletes status and repeated WBC exposures.
Costello 2011 Effects of whole body cryotherapy (-110) on proprioception and indices of muscle damage
Hausswirth 2011 Effects of whole body cryotherapy…
Sellwood 2007 Ice water immersion and DOMS
Banfi 2009 Effects of whole body cryotherapy on serum mediators of inflammation