Can getting hot and cold improve your muscle recovery after tough training sessions? We asked the experts to explain everything about cryotherapy and saunas.
After a tough workout, how do you support your body’s recovery? Perhaps you follow up with a protein shake to rebuild muscles or end the day with some relaxing yoga to stretch out tightness. These techniques are classics for a reason: they work. But more and more people are turning to alternative therapies to support their body.
According to exclusive research from ClassPass, post-workout practices are on the rise – and we’re all looking at temperature control to feel better. The fitness and wellness booking site reported that cryotherapy and sauna are in the top three most popular bookings, beaten only by the more traditional sports massage.
Kinsey Livingston, VP of partnerships at ClassPass, says: “Both activities promote healthy blood flow and aid in post-workout recovery, but there is one massive difference: cryotherapy blasts you with cold air between -120℃ and -150℃, whereas the sauna is for those who prefer the heat, climbing up to 88℃.”
But is getting hot and cold good for you? We dug into the research.
Cryotherapy for muscle recovery
Cryotherapy is a type of cold therapy which, on ClassPass, is most commonly booked after boxing workouts. While ice baths and cold showers have been famous recovery tactics for years, whole body cryotherapy is a slightly newer and more high-tech version. For most cryotherapy clinics, it involves stepping into a tank at extremely cold temperatures to help the muscles recover.
“Cryo is a technique that’s used to expose the body to extremely cold temperatures. There are milder forms of cryotherapy, like ice baths or using ice packs, but the tanks can expose people to temperatures of around -150℃,” explains Kerry Dixon, personal trainer and athlete, who frequently uses cold therapy in her recovery.
“The extreme freeze helps to remove abnormal muscle tissue that can lead to injury by reducing blood flow to the area. When your body warms up, fresh blood rushes back to the area which helps with faster healing,” she adds.
But some studies suggest the benefits of cryotherapy go beyond just the blood flow. In a 2014 review from the Journal of Sports Medicine, cryotherapy was shown to increase the body’s parasympathetic effect – meaning the nervous system moved into the rest and recovery state. The paper also found that it can decrease markers of injury: in rugby players who used cryotherapy tanks for five consecutive days, there was a 40% decrease in creatine kinase activity, a key marker of strenuous exercise.
In a 2017 paper from Frontiers in Psychology, researchers reported that after using tanks, people had less muscular tiredness and pain than those who used other recovery techniques. While they weren’t sure if that’s a psychological or physiological response, it does suggest that the body can heal faster with cold temperatures.
“You shouldn’t stay in a cryo tank for more than around three minutes, and you should do it between one to five days a week,” suggests Kerry. If you can’t get to a tank, osteopath Anisha Joshi says that she “uses hydrotherapy to complement my treatments”. She recommends icing a specific area for 10 minutes, three times a day, to vasoconstrict the blood vessels and then allow the muscles to be flooded with oxygenated blood.
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Sauna for muscle recovery
Saunas may be something you associate with your grandparents at their local health centre but they’re now also a favourite of those who spin, according to the ClassPass research. Saunas have huge health benefits, ranging from cardiovascular improvements to lower blood pressure and supporting athletes recover from training.
“Temperatures can vary between 65-90℃, so it’s very hot,” says Kerry. “This is really about stimulating that healthy blood flow and improving circulation. The nutrient-rich blood will be rushing to all of the body’s key areas to help with recovery.”
A 2015 study from Finland found that both traditional saunas and newer infrared saunas help the neuromuscular system to recover after strength and endurance training. And in a 2018 paper from the Sports Medicine journal, researchers found that heating muscles, including in a sauna, can even lead to an increase in muscle mass by “promoting muscle cell differentiation and altering the expression of various genes, kinases and transcription factors involved in muscle remodeling”.
And it’s not just useful post-workout: in another 2015 study, this time published in the Asian Journal of Sports Medicine, researchers found that using a sauna before exercise led to a smaller decline in muscular strength throughout the workout. Essentially, the body was less easily fatigued and participants could do more during their session.
“It is possible that sauna hyperthermia appears to improve left ventricular function… [and] helps to bring fresh blood, oxygen, nutrition and hormone to the muscle which is crucial for its efficient function,” the researchers wrote.
“If you have space, you should try to take advantage of the increased blood flow by stretching during your sauna session,” suggests Kerry. “As the body is in such a relaxed, oxygenated state that your flexibility will be greater and you can hold your postures much better.” Emma Obayuvana, fitness trainer from the Strong Women Collective, enjoys a gentle, passive stretch during a sauna.
“I like doing really gentle stretches such as neck circles or shoulder rolls to relax the muscles after my workout. For me, using a sauna is also about the mental relaxation too. When your body is under an extreme temperature, it’s a time to focus on your breath and quieten your mind after a stressful workout,” she says.
Kerry advises using a sauna two or three times a week, for no more than half an hour at a time due to the dehydrating impact. “Always try to take water in there if you can,” she adds.
So is the increased interest in heat treatments justified? It appears so. “None of this means you won’t feel sore the next day, or can go super hard in your training. But it should mean that recovery is sped up and your body is more relaxed,” says Emma.
For more recovery techniques, try our Strong Women Training Club mobility workouts.
Chloe Gray is the senior writer for stylist.co.uk's fitness brand Strong Women. When she's not writing or lifting weights, she's most likely found practicing handstands, sipping a gin and tonic or eating peanut butter straight out of the jar (not all at the same time).