Dr Kat Arney, The Naked Scientists
It’s time for our regular mythconception, and this week Kat’s been chilling out – literally.
Kat - If you’re an elite athlete at the top of your game – or even just a keen amateur or weekend warrior – you’ll want to know how best to look after your body. One technique, used by sportspeople ranging from Andy Murray to Jessica Ennis-Hill is to pop yourself in an ice bath after exercise, to speed up recovery, reduce inflammation in the muscles and boost repair. At least, that’s the theory, but an increasing number of research studies are showing that it doesn’t actually have that effect.
The latest research, led by Australian and Norwegian scientists, looked at nine young men who were training a few times a week. They either sat in water at a chilly 10 degrees Celsius, or did a low-intensity warm down on an exercise bike. The scientists took small samples from the sporty chaps’ muscles, and discovered that exercise causes the muscles to flood with inflammatory immune cells, and increase the activity levels of genes involved in inflammation. Yet there was no difference between the two ‘cool downs’ in terms of the levels of molecules associated with stress and inflammation. Of course, this was only a small study, and was just men, but it’s not the only one to show that ice baths don’t help recovery.
A 2007 study in the Journal of Sports Sciences found that men who plunged themselves into an ice bath after a gruelling 90 minute sprint session had no differences in the levels of a molecule called creatine kinase – which is a marker of muscle damage – compared with those who skipped the cold soaking, although there were a few other molecular markers of recovery that did reduce with a dunking. A 2014 study of rugby players taking part in a simulated match showed that cold water baths had no effect on their recovery. People have even tested different timings and temperatures – but it doesn’t make a difference. Other studies have even found that ice baths might actually delay the recovery process. For example, one study testing sprinting cyclists found that a ten-minute cold water bath reduced their performance when they were asked to sprint again an hour later, compared with an active warm down.
The other thing to consider here is that although a cool shower after getting all hot and sweaty on the track or pitch might be lovely, freezing ice baths are pretty unpleasant. And given the lack of solid evidence showing that it’s helpful – and some showing that it’s actively not – why do people still go for a dunk in the ice? In fact, the main benefit seems to be psychological – athletes think that such a horrible thing must be doing them good, and there’s enough sciencey-sounding stuff about reducing inflammation to make it seem like a good idea. Plus, ice bath studies suggest that people who take the plunge say they feel less sore than they would have been without the ice bath. So what do we know about the scientifically-proven ways to recover after exercise? One thing that’s often mentioned is massage. However, an analysis compiling many studies of massage, known as a meta-analysis, carried out in 2016 concluded that the benefits of massage – if any - are small, and may only apply for certain types of exercise rather than a panacea for every athlete. But, again, it does feel very nice and probably has a psychological benefit if not a physical one.
Anyway, as far as I’m concerned, the only ice I’m interested in after exercise is the stuff that clinks in my glass of gin and tonic. Cheers!