Plunging into a frigid bath, aka an ice bath, is a popular recovery technique that some athletes and regular exercisers swear by. Often, people do it to help reduce the effects of DOMS (delayed onset muscle soreness). Others say ice baths help boost their energy levels and encourage weight loss. While these claims may be valid, it’s important to note that the science behind some of these benefits is lukewarm at best.

In general, dipping into icy waters causes the blood vessels in your submerged body to narrow (known as vasoconstriction). This forces your blood to move toward major organs like your heart, brain and lungs to bring oxygen and nutrients to those areas. It also helps reduce inflammation caused by an intense workout and speeds up the body’s natural healing processes.

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But if you’re going to try a cold water dip, make sure it’s safe by starting out with the lowest temperature you can handle and slowly working up. If you’re uncomfortable or start shivering excessively, get out immediately. Chhabra notes that prolonged exposure to extreme temperatures can cause hypothermia, skin and nerve sensitivity, or cardiac issues.

Another reason why ice baths can be beneficial is that they increase the activity of brown fat cells. Brown fat is one of two types of fat cells in your body and burns calories at a higher rate than the more common white fat cells. This process can also lead to more muscle growth and improved metabolic health, including a lower risk of insulin resistance.