Cold room and ice bath – that’s why the sports stars want to freeze

In an episode of the comedy series “Ted Lasso”, one of the main characters, an English football star, sticks his head out of a dustbin full of melted ice cubes when he is depressed after a match.

Immersion in ice water has become a recognizable method among football teams and other athletes, which should promote recovery.

In recent years, the much more advanced technology with so-called cryo-chambers has begun to spread.

Formula 1 driver Lewis Hamilton shows for example on Instagram how he stands and jumps and freezes in just his underwear together with his fitness trainer in a room with a temperature of 98.7 degrees minus.

According to Hamilton’s fitness trainer Angela Cullen can lead the treatment to a number of things, from preventing dementia to weight loss.

But it is difficult to research the effects of the cryo-chambers, where liquid nitrogen is often injected to cool the air. The same applies to ice baths, which also go under the term cryotherapy.

Tommy Lundberg, who researches physiology at Karolinska Institutet, points to several reasons for this. On the one hand, it is not possible to “blind” studies by hiding from the subjects the type of treatment they receive, which means that there may be an expectation effect in those who participate. It is also difficult to measure whether a sports performance has improved or not.

– If you take a football team, it is very difficult to say whether they have actually performed better on the football field, so you have to go on indirect factors.

There are also objective indicators which one can measure. If you look at the entirety of the studies that exist where blood markers for muscle injuries and exercise pain have been measured, there is probably a small positive effect there, says Tommy Lundberg.

– Then it is much more unclear and ambiguous in the research whether it affects the recovery of muscle function and strength. There are some such indications, but it is not very clear that this would be the case.

There is most evidence for the subjective experience of cooling down – you feel fitter and fresher.

There are also studies that point to the unwanted effects of cold treatment.

What you are looking for with cryo-chambers or ice baths is to promote recovery. But it can be the case that at the same time you worsen the effect of the training you have performed.

– It has been seen in several studies, quite convincing, I think, that if you apply this all the time, it can inhibit the training adaptation instead. If you constantly try to dampen the normal response after training, maybe you can get a little better recovery, but you might kill a little of the training adaptation, says Tommy Lundberg.

To get more information on how, when and for what purpose you can use both cold baths and hot baths, researchers at Örebro University are currently conducting a study where the players in Örebro SK’s men’s elite football team are test persons.

The state of knowledge is particularly scarce when it comes to football and cold baths, says Peter Edholm, researcher in sports physiology who is leading the study.

When you do hard training and stress the muscles and the body, three things happen that can be relevant to understand what effect cooling can have. One is that damage or changes occur in the muscle cells. The second is that some of the fluid that is in the muscles is pushed out and ends up in the tissue between muscles and blood vessels. The third is that you empty the depots of energy.

– All these things contribute to the fact that you may get a little inflammation in the muscles and become a little swollen and sore. It contributes to impaired muscle function, says Peter Edholm.

If you then bathe in cold water or ice water means the lowered temperature causes the blood vessels to constrict.

– If the blood vessels constrict, you can imagine that the inflammation is reduced, we know that cold reduces inflammation. It is conceivable that the swelling will decrease. And constricted blood vessels may help push the fluid back to the right place. All this makes you feel more alert and it could potentially be what contributes to restoring muscle function faster, says Peter Edholm.

But, then you come to the next question. For the point of exercise is that you want the body to react to it, in this way you achieve an improvement.

– If you manage to restore some of these factors faster, the signals to the body that “I’m under stress, build me up” may be dampened. And then maybe you dampen the training response over time, says Peter Edholm.

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It could mean that cooling can be good to use during a tournament or intense training period when you want to recover and get back fit as quickly as possible – but that it should not be used during a period of build-up training. But it does not have to be that simple either, says Peter Edholm.

There are research results that indicate that some training effects deteriorate but not others. And it can be beneficial to be more alert even during a training period, to be able to train harder and more often.

Peter Edholm hopes to get more information on which sports it can be beneficial to take a cold bath, and when and how during the competition and training season. But despite the fact that many questions are unanswered, cooling is used in many places in elite sports.

As for the ice bath, it is general recommendation to stay in it one minute per degree, it is common with ten minutes in ten degree water. But it is not clear what is optimal.

In cryo-chambers with temperatures between 100 and 200 degrees below zero, you are only there for a few minutes. Water dissipates heat much better, which means that it is better tolerated to be in cold air than in cold water.

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There is even less research on cryo-chambers than on ice baths, but the mechanisms are basically the same. One study showed a better effect on ice baths than cryo-chambers, but what works best is not known. It is clear that cryo chambers are expensive, while cold baths are cheap.

– The question is whether a cold water bath is not enough, or whether it is even a little more efficient, says Peter Edlund.

There is also new technology, so-called PCM, phase change material, material that can be worn on the body to lower the temperature for a long time.

Although there is weak evidence for cooling to work, it may be rational to use anyway, as long as the risk of negative effects is small.

– In professional clubs, the reasoning is often that if the players think it works, it is good even if it is sugar pills. Therefore, I think it is used quite a lot even if sports scientists who are employed in the organizations know about the research situation, says Tommy Lundberg.

And so he says he might use it if he worked in a club.

– There is an expectation effect, you do something with the athletes, they may themselves say that they feel better, and even a small effect can be important in elite sports.

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Cryochamers are marketed also for ordinary exercisers, but if you train between two and five days a week and at the same time have a job and maybe children to take care of, then that is something else you should think about, says Peter Edholm.

Eating right, getting enough sleep and resting both mentally and physically immediately after exercise is significantly more important than spending half an hour on more advanced things like massage or cryotherapy, he says.

– And if you turn it around – often elite athletes have already maximized sleep, they eat well, and they have nothing else to do during the day. For them, there is room for things like this. It is a completely different thing than what the exerciser is exposed to.

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