Cold Exposure and Winter Immune Readiness

Does cold plunging keep you from getting sick?

We hear this question more once October arrives, and it's a fair one to ask. Colds start making the rounds, kids bring home whatever is going around school, and anything that might tilt the odds your way sounds worth a try.

The short answer is that there's some intriguing research, and nothing yet showing that cold water keeps you from catching a cold or the flu. The longer answer is more useful, because the studies that exist measured some surprising things. Here's what they found and how we'd use it.

Where doctors land right now

In Cleveland Clinic's guide to cold plunges, sports medicine physician Dominic King, DO, includes immune support in the list of possible benefits and describes that evidence as preliminary. He points to sore muscles, mood, and alertness as the areas with more support.

Forbes Health's cold plunge explainer reaches a similar place. Craig Van Dien, MD, a physical medicine and rehabilitation specialist, tells Forbes the evidence for better immune function is low quality, and that muscle soreness has the stronger case.

So two sources that are open to cold plunging both stay careful on immunity. That's a good frame for reading the studies below.

Three studies worth knowing about

The Dutch cold shower trial

In 2016, researchers in the Netherlands asked about 3,000 working adults to finish their usual hot shower with 30, 60, or 90 seconds of cold water every day for a month. A comparison group showered normally. The cold shower groups called in sick about 29% less often over the following months.

Here's the interesting part. The number of days people reported feeling ill didn't change. They got sick about as often, and more of them felt well enough to keep going to work. How long the cold lasted didn't seem to matter much, either. Thirty seconds did about as well as 90.

The endotoxin experiment

A 2014 study in the journal PNAS trained 12 healthy men for about 10 days in a practice that combined breathing exercises, meditation, and cold exposure. Researchers then injected them with a bacterial toxin that reliably causes short-lived, flu-like symptoms. Compared with 12 untrained men, the trained group reported fewer symptoms, released more adrenaline, and showed a smaller inflammatory response.

It's a striking result. It also involved a lot of breathing work alongside the cold, a very small group, and a lab-made immune challenge that's quite different from catching a virus on a plane. What it shows is that the nervous system can influence how the immune system responds. Whether a daily plunge does the same for you hasn't been tested.

People who swim in icy water all winter

Several studies of regular winter swimmers have found differences in some immune markers compared with people who don't swim. These tend to be small, observational studies, and winter swimmers often differ in other ways too, including fitness, sleep, and general health habits. It's hard to credit the cold alone.

What we'd take from it

Cold exposure has real, measurable effects on the body. It sets off a surge of norepinephrine and adrenaline, changes circulation, and in some studies shifts how the immune system reacts to a challenge. None of that has been shown to mean fewer colds for the average person.

The Dutch result is the one we find most practical. Fewer sick days with about the same amount of illness suggests the benefit people notice may be in how they feel and function when they're run down. That's worth something on its own. It's also a long way from protection.

For most people, getting through winter well still comes down to familiar things: enough sleep, regular movement, handwashing, managing stress, and the vaccines your doctor recommends. Cold plunging fits alongside those habits and can make some of them easier. Think of it as one more item on that list.

Plunging through the cold months

If you plan to keep plunging as the weather turns, a few adjustments help. Our guide to ice baths in winter covers the seasonal side in more detail.

Keep sessions short. Cleveland Clinic suggests newer plungers start between 50 and 59°F for one to two minutes, stay under five minutes in total, and avoid water below 40°F. Winter doesn't change those numbers. What changes is the air you step out into.

Plan your exit before you get in. If your plunge is outside, have a robe, towel, and dry layers within reach. Warm up gradually with light movement, like a brisk walk or some easy stretching, instead of jumping straight into a hot shower.

Pair it with heat if you have both. Many people find a sauna session makes winter plunging far more comfortable, and the contrast has its own appeal. Our sauna and cold plunge combo guide walks through how to sequence the two.

Skip it when you're sick. If you're already fighting something off, the stress of cold shock is more than your body needs. Rest, and come back with a shorter, slightly warmer session once you feel like yourself again.

Before you start

Cold water raises your heart rate and blood pressure quickly and can cause a reflexive gasp when you first get in. Cleveland Clinic advises people with heart disease, high blood pressure, diabetes, poor circulation, peripheral neuropathy, or cold agglutinin disease, and anyone who is pregnant, to talk with a doctor first. Enter slowly, keep your breathing steady, and get out if you feel numb, dizzy, or can't settle your breath. Experts quoted by Forbes also recommend never plunging alone.

Where this leaves us

If you enjoy cold plunging, winter is a fine time to keep it up, and there's early evidence it may help you feel better on days when you're a little run down. It isn't a shield against cold and flu season, and the researchers studying it don't claim it is. Keep the sessions short and the exits warm, and let it be one part of a winter routine that also covers sleep, movement, and the basics.

Sources

• Cleveland Clinic, "Are 'Cold Plunge' Ice Baths Good for You?" (May 8, 2026)
• Forbes Health, "Cold Plunges: Health Benefits, Risks And More" (November 25, 2025)
• Plunge, "4 Amazing Benefits of Ice Baths in the Winter"
• Plunge, "7 Powerful Benefits of Sauna and Cold Plunge Routines"
• Buijze et al., "The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial," PLOS ONE, 2016
• Kox et al., "Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans," PNAS, 2014