Is it true that … cold water plunges boost immunity?

Feeling energised after a cold dip may just be your body’s shock response –and increased immune cell activity doesn’t always mean fewer infections

‘It’s a long-held belief that taking to the waters is good for your health,” says Mike Tipton, a professor of human and applied physiology at the University of Portsmouth. From Roman frigidariums to Thomas Jefferson’s foot baths, cold immersion has long been seen as curative. But does modern science support the idea that it boosts immunity?

The answer: it’s complicated. While cold water immersion does activate the body, that’s not the same as strengthening the immune system. “When you immerse yourself in cold water, your body undergoes the cold shock response,” says Tipton. “You get rapid breathing, a spike in heart rate and a surge of stress hormones such as adrenaline and cortisol.” This may explain why people feel more alert or energised after a cold dip. But does it mean you’re less likely to get sick?