Do Cold Plunges Reduce Inflammation? Two New Reviews Say They Ease Sore Muscles Instead

The first hour goes the wrong way

The idea online is simple. Sit in icy water every day, and the cold "flushes out" inflammation, helps you fend off colds and speeds recovery.

A 2025 meta-analysis put that to a test. A meta-analysis pools the results of many studies. This one gathered 11 studies of healthy adults, 3,177 people in all, who used ice baths, plunges or cold showers in water of 15 °C or colder.3

Right after the cold water, inflammation markers were higher, not lower. They were still higher 1 hour later. The authors called it "an acute inflammatory response."3 Stress did drop, but only when measured 12 hours later, not right after or a day later.3

A short rise after a stressor is one thing. The claim people make is about something else: the low, steady inflammation that lingers for months and shows up on a blood test. So we looked for that.

Where cold water earns its reputation

Start with what cold water does well. Fifty-two studies went into a 2022 meta-analysis of people who soaked in cold water after hard exercise. After high-intensity workouts, they had less muscle soreness and felt more recovered the next day.4 Their strength did not come back any faster.4

Right after a cold plunge, inflammation markers went up, not down.From a 2025 meta-analysis in PLoS One

A 2026 network meta-analysis of 51 trials, with 1,243 people, found the same pattern. Cold water eased soreness at 1 hour and at 24 hours, but not right after the workout.5

The newest umbrella reviews, which look across many meta-analyses at once, agree on the headline. One reviewed 15 meta-analyses covering 161 studies and found less soreness for up to 96 hours.2 Another, published this year, reviewed 14 and called soreness the "most consistent" benefit.1

But that second review spotted a problem. The same studies kept showing up in review after review: 99 of 165 study groups appeared in at least two. So the agreement does not mean the finding was repeated by separate teams.1 It rated 12 of the 14 reviews "critically low" in quality, and said how much the soreness relief matters in real life is still unclear.1

What happens to CRP and IL-6

CRP (C-reactive protein) and IL-6 (interleukin-6) are two blood markers that researchers use to track inflammation.5 If cold plunges cooled inflammation, these are the numbers you would expect to fall.

Mostly, they did not. A 2023 meta-analysis of 20 studies found no sign that cold water changed CRP or IL-6 in the 48 hours after exercise.6 The 15-review umbrella found no clear effect on either one for up to 72 hours.2

There is one exception. The 2026 network analysis found that cold water lowered IL-6 right after exercise and at 24 hours.5 The 14-review umbrella called the blood findings inconsistent, and concluded that the evidence "does not support a uniform benefit" for inflammation.1

What about plunging often, for weeks? In a 2026 trial, 16 healthy men did interval running 3 times a week. Nine of them sat in water at 11.2 °C for 15 minutes after every session. After 5 weeks, inflammation markers in their muscles had not changed.7

For the slow, lasting kind of inflammation, the trials are thin. The 2025 review said its evidence came from few randomized trials with small samples, and called for better trials of long-term effects.3

Does it help you fight off colds?

Here the picture is murkier. The 2025 review found no change in immune function right after cold water or 1 hour later.3 In its wider reading of the studies, one result stood out: 29% less sickness absence among people who took cold showers.3

One small trial tested daily cold showers directly. Sixty healthy adults took cold or hot showers every day for 90 days. The cold group's blood showed higher levels of antibodies and of two immune signals, IL-2 and IL-4. TNF-alpha, an inflammation marker, did not differ between the groups.9 The trial measured blood levels, not how often people got sick, and the authors called for larger studies.9

The catch for muscle growth

If you lift weights to get stronger, timing matters. In a landmark trial, 21 active men did strength training twice a week for 12 weeks. After each session, they spent 10 minutes either in cold water or doing an easy cool-down.8

The cool-down group gained more strength and muscle. Their type II muscle fibers grew 17% in size. In the cold water group, they did not grow.8 The 15-review umbrella reached the same verdict: cold water after exercise held back strength and muscle gains, and may do so when used again and again.2 It advised using cold water for specific moments, not after every session.2

Endurance training looked less affected. In the 5-week interval trial, cold water did not change fitness gains or running performance.7

The first minute is the risky part

Cold water triggers a reflex called the cold shock response. You gasp and breathe fast, your heart can fall out of rhythm, and the risk of drowning goes up.10 Going fully under cold water can trigger irregular heartbeats even in healthy volunteers. Researchers think it may explain some sudden deaths in people who are vulnerable.11

The good news is that the body adapts. After about 4 dips, the reflex starts to fade. In pooled studies, the jump in heart rate on entry fell by about 14 beats a minute.10 A review of cold water swimming warned that people new to cold water face a risk of death, and that first shock is part of it. Benefits seemed to show up in healthy, experienced people who build up slowly.12

The bottom line

Put the studies side by side and a clear shape appears. Soreness fades a bit faster. CRP and IL-6 mostly stay put. In the first hour, inflammation markers climb. And after lifting, the cold can cost you muscle. A cold plunge is a recovery tool for tired legs, not a way to cool the slow inflammation a blood test measures. If you love the cold, keep it. Just ask it to do the job it can do.