Cold-water swimming might sound unpleasant, but research suggests regular dips in cold water can improve health and longevity.
Bare early March trees rake a pale blue sky, patches of snow surround the bay, and the chilly Salish Sea undulates gently in front of us. Usually I would be exclaiming at the beauty, but today it just looks way too cold, because we’re about to go for a swim. The health benefits of cold plunges have been reported since ancient times, and cold-water swim clubs have existed around the world for decades—but can we really just get in that?
Yep, says my friend: “You just go in.” We shed our layers of winter clothes and stride forward in bathing suits. The shock of the water hits like a lightning bolt. I hear gasping and shrieking; it’s me.
But then the near-pain turns into tingling exhilaration, and I want to stay in forever. Our swim lasts for three minutes, but the feeling of calm and well-being lingers for days. It’s like I hit an internal reset button.
It’s a feeling that habitual cold-water swimmers know well. Regular cold-water swimmers will often tell you that they rarely get sick—and if they’ve had chronic pain or depression, their symptoms have reduced significantly.
The anecdotal evidence is compelling, and in recent decades, research has been building in its favor. After cold-water immersion, dopamine production more than doubles, while cortisol (stress hormone) levels decline. Studies have documented self-reported relief from rheumatism, fibromyalgia, and asthma, along with significantly better memory, mood, calm, and energy compared to controls who didn’t swim.
Temporary immersion in cold water has been shown to increase both red- and white-blood-cell count and even reduce the frequency of respiratory infections in COPD sufferers. Medical research is also starting to examine cold water’s effects on depression, starting with a much-discussed British Medical Journal case study in which a woman with major depressive disorder and anxiety was able to control her symptoms with a weekly cold-water swim.
Why does it work? No one knows for sure, but scientists and alternative practitioners alike have speculated that humans evolved to function well under certain physiological stressors, like uncomfortable heat and cold—and that a “lack of thermal exercise” may be one of the underlying mechanisms of modern-day brain and body fragility.
At the end of the day, it’s not whether something works for everybody: it’s whether it works for you. Me, I’m going back in.
Here are a few tips to stay safe and get the most out of your cold-water swim.
1. Start small. Three to five minutes is enough for a first swim.
2. Go with a buddy. It’s always safer with two.
3. Wear shoes. Cold-water swimmers don’t wear wetsuits, but they often wear water shoes.
4. Go slow. Find a shallow-to-deep gradient where you can control your rate of immersion, and don’t ever dive in. The body’s normal cold shock response elevates the heart rate and can cause involuntary deep inhalation.
The 30-second version: a cold shower. Many cold-water swimmers love the outdoor and exercise components of cold-water wild swimming, but a recent randomized, controlled study of more than 3,000 people concluded that even a cold 30-second shower every day reduces sick-day absences by a whopping 30%.
If you have a heart condition, make sure to talk to your doctor before getting in. (Even if you don't have a heart condition, a chat with your doctor is always a good idea before starting new physical activities.)
Keep reading: If Michael Phelps battles depression, so can you.