Cold dives are all the rage right now. The #coldplunge hashtag on TikTok has over 1.1 billion views and features thousands of videos of people shivering and gasping through a bath of freezing water.
The toe numbing practice is endorsed by celebrities, athletes, influencers, and everyone in between.
Many say cold plunge benefits include relieving muscle soreness, aiding recovery after workouts, reducing inflammation and boosting immunity. Some report that cold dives also have mental health benefits, such as improved clarity and reduced depression or anxiety.
But what does science say about the benefits of cold dives? We spoke to cold dive experts about what people should know before they get started.
What is a cold plunge?
A cold dip involves fully immersing the body in cold water, whether it is a bathtub, reservoir, swimming pool, or natural body of water, such as a lake. or the ocean. It is also called cold water immersion or cold water swimming. Ice baths are a type of cold dive, usually on the lower end of the temperature spectrum.
Although cold dives have grown in popularity recently, the practice has been around for about as long as people have been near water, Mike Tipton, professor of human and applied physiology at the University of Portsmouth, tells TODAY .com.
“Going back to Hippocrates and even Thomas Jefferson, Darwin and Florence Nightingale all practiced cold water immersion,” says Tipton, who leads research into cold water swimming at the University of Portsmouth’s Extreme Environments Laboratory. .
How to cold dive
A cold dip involves immersing yourself in cold water – either quickly in and out, or for several minutes. During a cold dip, the water is usually between 50 and 70 degrees Fahrenheit or about 10 to 20 degrees Celsius, Dr. Kristi Colbenson, sports physician and emergency physician at the Mayo Clinic, told TODAY.com.
The duration of a cold dive can vary depending on water temperature and comfort level. The colder the water, the shorter the submersion should be, experts note. In general, cold dives typically last between five and 10 minutes, adds Colbenson.
The water should not be colder than about 53 degrees Fahrenheit or 12 degrees Celsius, in which case the risk of skin and tissue damage or other adverse effects increases. The ideal temperature for swimming in cold water is a little warmer, around 65 to 75 degrees.
How long to cold plunge
Literally, a quick dip in and out counts as a cold dip, but how long does it take for a cold dip to work? It takes three to five minutes for the cold to penetrate beyond the skin, Colbenson says, at which point it begins to have a neuromuscular effect.
She adds that cold dives typically last between five and 10 minutes, and Tipton warns that diving for more than 10 minutes can increase the risk of being physically injured from the cold.
People have long touted the benefits of cold water, but they’ve also warned of the risks, Tipton says, and throughout history it’s been seen as both a panacea and a danger. for health. So what do we now know about how cold water immersion affects the body?
Benefits of Cold Plunge
From a physiological perspective, the greatest benefit of cold water immersion appears to be improved recovery, pain perception, and delayed muscle soreness, Colbenson says.
A systematic review published in the journal Sports Medicine in February 2022 suggested that cold water immersion was an effective recovery tool after high-intensity exercise, especially HIIT exercisesTODAY.com previously reported.
Cold dives can also reduce inflammation in the body. For what?
When the body enters cold water, it causes blood vessels, especially in the extremities, to constrict to keep heat in the core of the body near the heart, experts say.
“It slows down and inhibits blood flow to the legs and arms and pushes (blood) further to the central aspect of the body,” says Colbenson. “By doing this, you decrease this natural inflammatory response that occurs after exercise.”
However, the reduction in inflammation after cold water immersion is likely temporary, experts note.
“When you look at the literature, it helps with recovery and inflammation, especially if you’re an athlete competing or training,” adds Colbenson.
A cold dive can also induce a heightened state of stress and send us into “fight or flight” mode, notes Colbenson, and the body will release a surge of norepinephrine and cortisol, the stress hormone.
Also known as the cold shock response, the initial gasping, hyperventilating and increased heart rate after jumping into freezing water can be dangerous – but it can also be the basis for some of the benefits. physical, says Tipton.
“The belief is that if you constantly expose yourself to stress in a meaningful and structured way, your body will actually respond by improving its ability to respond to everyday stress,” Colbenson says.
However, evidence that immersion in cold water improves the body’s immune function is lacking, experts note.
“From an immunological standpoint, or your ability to fight infection, I caution against that. … There hasn’t been a good study that says there’s a decrease in the propensity to get an infection if you use cold water immersion,” adds Colbenson. .
The lack of solid scientific evidence seems to be a recurring theme. “While we know a lot about the science of harms, we know a lot less about the science of benefits,” says Tipton, adding that more studies such as randomized controlled trials (the gold standard of research) are necessary. “We have hypotheses but not yet definitive experimentation,” he adds.
Can cold dives improve mental health?
When it comes to the mental health benefits of cold plunges, these are even less studied or understood, experts note. However, there are many anecdotal accounts of the stimulating effects of cold water immersion and a few possible theories.
In the short term, cold dives can increase dopamine and endorphin levels, says Colbenson, which can contribute to feelings of euphoria and increased mental clarity or focus right after.
“This is how our body responds to stimuli that threaten us – we are ready to be clear in our ability to respond,” adds Colbenson. However, mental clarity after a cold dive appears to be short-lived, she adds, and there is no literature showing this is maintained over time.
The anti-inflammatory effects of cold water may also play a role. “There may well be, according to some models, an inflammatory component to depression and we know that repeated cold immersions decrease (inflammation),” adds Tipton.
Similarly, the hypothesis that repeated exposures to cold water can make the body better able to cope with other stressors may apply to mental health barriers, says Tipton, who co-author of a case study on a 24-year-old woman whose depression was treated by swimming in cold water.
The patient felt an immediate improvement in his mood after each immersion, the authors note, and experienced a gradual and sustained reduction in symptoms over time. A year after beginning to swim in cold water, the patient would have been depression- and medication-free, Tipton says. “There is something going on,” he adds, but what exactly it is remains unclear.
There are several other factors that can impact a person’s mental state after cold water immersion or swimming, experts note. “They get exercise, they feel like they’ve overcome a challenge, and they have a sense of accomplishment,” Tipton says, adding that cold dives can also be a social activity.
“Even if it’s a placebo effect, it’s still an effect,” he adds. “There are a lot of potential things that could happen and we need more experiments to isolate the active ingredient, to see what makes a difference,”
Cold Diving Hazards
There’s a right way and plenty of wrong ways to do a cold dip, experts note, and some people should avoid it altogether.
“We’ve spent probably 40 years looking at the dangers associated with cold water — from drowning to sudden cardiac death,” says Tipton.
Raising the hormone norepinephrine from cold water increases heart rate, blood pressure and breathing rate, Colbenson says. For young, healthy people, it can be tolerable, she adds, but for people with a history of heart disease or heart problems (such as arrhythmias), it can be life-threatening.
People with a history of heart disease, vascular disease, or conditions such as high blood pressure should probably avoid cold dives, Colbenson says — regardless, everyone should check with their doctor before trying the cold water immersion to be safe, experts note.
People should also avoid diving into cold water alone or swimming alone, Tipton warns. “We want to make sure people are doing it safely, and that means doing it in a controlled environment with other people or supervised,” says Tipton.
Some people may be tempted to crank it up a notch or lower the temperature, but experts warn against overindulging. “Colder isn’t necessarily better, and this cold shock response is potentially dangerous if you’re in an uncontrolled environment,” says Tipton.
“We know the response maximizes between 10 and 15 degrees Celsius, so you don’t need diving longer (or beyond about 10 minutes) isn’t always beneficial either, he adds. “You are more likely to become physically incapacitated by the cold.”
Practicing cold water immersion in a sensible, risk-minimizing way maximizes the chances of it being beneficial, Tipton says.
This article was originally published on TODAY.com