Hailey Bieber says cold plunging helped anxiety, experts weigh in

While there may be minor benefits to cold water therapy, research on the advantages is sparse.

“Nobody knows exactly why it even helps you,” Dr. Tracy Zaslow, a primary care sports medicine physician at the Cedars-Sinai Kerlan-Jobe Institute said in a blog post. “Maybe it’s changes in adrenaline or cortisol — or even dopamine. There are a lot of hypotheses, as opposed to data.”

Possible health benefits of cold water therapy include exercise recovery, pain reduction, improving circulation, boosting mood and building resilience, according to a medically-reviewed article in Everyday Health.

But of all the possibilities, the one backed with the most evidence is soothing sore muscles.

“There have been a couple of studies showing that there may be some decreased soreness after people were immersed in cold water for about 10 minutes versus those who did not do any cold therapy,” Dr. Zaslow said. “When you’re in cold water, your blood vessels constrict so there’s less blood flow to the area, then there’s less swelling and inflammation leading to less pain.”

As for helping with mood and anxiety as Bieber claims, this has yet to be scientifically proven.

A study published in February 2000 in the European Journal of Applied Physiology suggested that immersion into cold water can increase dopamine concentration by 250%, but Dr. Zaslow feels more research needs to be conducted in order to prove the correlation.

“The study that showed it might be helpful for mental health looked at people who took a course in swimming in cold seawater,” Dr. Zaslow says. “But exercise can improve your mood and wellbeing. To me, it’s a soft case that it was the cold water providing the aid.”

Additionally, the American Heart Association has warned against the risks of a cold plunge, suggesting that “you are not a polar bear.”

Sudden plunging into cold temperature waters can cause what’s known as the “cold shock response” — a sudden, rapid increase in breathing, heart rate and blood pressure, which can cause a person to drown if they involuntarily gasp while submerged. Since the shock adds additional pressure to the heart and causes it to work harder, this practice is especially dangerous for those with a history of cardiac issues.

Lee Hill, an exercise scientist and a postdoctoral fellow at the Research Institute of the McGill University Health Centre in Quebec, Canada, told the AHA that the risk of hypothermia continues once getting out of the cold water, so it’s vital to immediately get out of the cold, wet clothes and change into warm ones.

The National Center for Cold Water Safety cautions that immersion in cold water under 60 degrees Fahrenheit can kill a person in less than a minute.

Other than a cold shock response and hypothermia, risks of exposure to cold temperatures can include frostbite, heart arrhythmias and even heart attacks, according to the AHA.

Zaslow suggests that, like all fitness and health trends, one should consult their doctor before taking part.

“It’s not a completely benign activity,” Dr. Zaslow said. “Talk to your doctor to make sure that no harm comes from a fun activity that is intended to help your health.”