Cold water immersion has become very trendy, but the science is mixed on whether a chilly dip delivers big benefits. While one study on athletes suggests that an ice bath may improve sleep quality, another shows it had no effect at all. As for mood, there is some older research that cold showers may help ease depressive symptoms, possibly because they trigger the release of endorphins—your body’s feel-good chemicals. Endorphins might also explain why some people say they feel more focused or alert after a cold shower. However, the placebo effect (the belief that a treatment works) may be responsible for any changes in focus or mood.

When it comes to pain, cold exposure has a relatively straightforward effect on the body—it constricts blood flow to the area where ice is applied, which brings down inflammation and numbs pain receptors. “You can almost think of it as a direct anesthetic,” says Dr. Dominic King, a sports medicine physician in the Department of Orthopaedic Surgery at the Cleveland Clinic.

King also notes that while ice baths relieve some symptoms, they don’t treat underlying conditions. For some though, addressing pain may be a crucial component of disease management. Dr. Alaa Abd-Elsayed, an anesthesiologist and pain management specialist at the University of Wisconsin, says that when it comes to chronic pain, alleviating discomfort and providing relief is essential. “If you don’t control the pain and it goes for four years, it becomes central, which means the brain starts being hypersensitized to the area that’s hurting,” he says. Finding a strategy that brings pain to a tolerable level, whether that’s heat, cold or another modality, is key to quality of life for people living with chronic pain, he adds. 

How to safely take an ice bath

Cold water immersion can shock the system, cause muscle spasms, and interfere with circulation, so submerging yourself in it may not be the right choice for everyone. If you’re curious about trying an ice bath at home, check with your doctor first if you have diabetes, heart disease, peripheral neuropathy and other nerve conditions, poor circulation, or an immune disorder called cold agglutinin. 

Start slow, says King. That could mean finishing your shower with a blast of cold water, or gradually lowering the temperature of your bath.

If you want to take the plunge and go straight to a cold bath, don’t go too cold. “We recommend starting at around 68 degrees Fahrenheit, 20 degrees Celsius, which is still really cold,” he says. You may not even need to add ice, simply filling the tub with cold water from the tap might be enough. If you want to try a colder dip, add small amounts of ice over time to work the temperature down to 53 degrees Fahrenheit—but no colder, cautions King. Use a thermometer to keep the temperature in check. 

Start with short baths, five minutes or less, working up to 10 minutes, if that feels good. “Some research shows that you really don’t get much more benefit after the first two or three minutes in an ice bath,” says King. 

You can buy a variety of vessels designed for ice baths that range in price from hundreds to thousands of dollars, but your bathtub also works just as well. If you decide to purchase a dedicated ice bath tub or barrel, make sure you can get out of it before filling it with ice and cold water.