Exposure to cold water is hot right now. From influencers touting the mental health benefits of cold showers to professional athletes swearing by ice baths for recovery, it’s become a serious wellness trend. Proponents claim it can sharpen focus, improve immunity, and even reduce inflammation.
But researchers say the evidence, while intriguing, is mixed. Small studies suggest that brief exposure to cold water, such as in a cold shower, can improve alertness and mood, but other research finds minimal or short-term effects. What is clear is that this practice triggers a cascade of physiological changes that can feel invigorating and, for some, therapeutic.
“When cold water touches your skin, your body is responding to a cold shock,” says Dr. Jonathan Leary, founder and CEO of Remedy Place, a wellness social club that offers guided cold plunges. “This basically means rapid breathing, a brief increase in heart rate and blood pressure, and a surge of stress hormones that make you feel wide awake.”
This type of cold exposure has been linked to improved mood and reduced stress, but the research is still emerging, says Dr. Neha Pathak, an internal medicine and lifestyle medicine physician. “Several small studies suggest that exposure to cold triggers the release of mood-enhancing neurotransmitters like dopamine and norepinephrine, thereby improving mood and concentration.” However, research in this area is “promising and not definitive.”
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An analysis of studies, published in 2025, found that after about 12 hours of immersion in cold water, people’s stress levels decreased and their sleep quality improved. And a 2015 randomized trial of more than 3,000 participants in the Netherlands found that when people ended their hot showers with 30 to 90 seconds of cold water, the number of sick days they took decreased by almost 30% (even though they didn’t get sick less often). While interesting, this evidence hardly proves the power of cold showers.
“We still need high-quality trials of dosing (duration, frequency, temperature) and long-term outcomes,” says Pathak. “It’s reasonable to say that exposure to cold can help, but that’s not absolutely the case.”
Being doused with cold water sets your sympathetic nervous system into gear. This releases adrenaline and norepinephrine, hormones that temporarily increase heart rate, alertness and blood flow.
Research shows that this type of stress response also mobilizes certain immune cells that help fight infections. In short periods, this can act as a wake-up call to your immune system.
A 2014 study found that people who underwent cold exposure training – such as cold water immersions – and breathing techniques could intentionally influence their immune response. When given endotoxin (a substance that typically triggers inflammation), those who practiced cold training produced fewer inflammation-controlling proteins and had milder symptoms compared to a control group of people not trained in these techniques.
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A cold swim can help invigorate you, but it shouldn’t be your only stress-relieving practice. “Immune response appears to be a direct correlation with stress reduction,” says Dr. Sirisha Vadali, a cardiologist at HonorHealth Women’s Heart Health in Arizona. “It’s not a perfect solution but rather a nice boost to already healthy habits.”
A cold shower is a quick, controlled stimulation, while an ice bath is a full-body immersion that quickly lowers core temperature.
Cold showers are gentler and easier to control. They are generally safe for most healthy adults, easy to incorporate into daily routines, and have a lower risk of shock, arrhythmias, and hypothermia.
Ice baths, on the other hand, are done in very cold water, generally less than 50°F (10°C). They trigger the same physiological responses but more intensely.
Dr. Parth Bhavsar, a family physician at Wellstar North Fulton Hospital in Georgia and a researcher in thermoregulation, explains that both techniques rely on cooling the skin to trigger blood vessels to constrict and release hormones.
“Ice baths cause a faster drop in body temperature and a higher release of adrenaline,” he says. “It also means a higher risk of heart rhythm disturbances, hypothermia and what is called post-drop, where your temperature continues to drop even after you get out.”
Cold showers aren’t for everyone. They can be risky for anyone with cardiovascular problems, high blood pressure or respiratory problems, Pathak says. She advises talking to your doctor before trying them if you have heart disease, circulatory problems, Raynaud’s syndrome, or are pregnant.
People with vascular diseases — “especially anyone with circulatory problems and uncontrolled high blood pressure,” Vadali says — should also avoid them, “as this could cause blood to be shunted inappropriately.”
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However, for most healthy adults, exposure to cold water can be safe if done gradually. “Repeated exposure to cold causes the body to transition between states of ‘fight or flight’ and ‘rest and digest,'” says Pathak. “This physiological flexibility may also translate into greater emotional or psychological resilience.”
Consistency matters more than intensity. Start around 68-70°F and gradually lower the temperature over time, experts suggest.
“A temperature of around 50 to 60°F for about one to three minutes is enough to reap the cardiovascular benefits,” says Vadali. “Anything below 50° for prolonged periods should be avoided.”
Pathak recommends getting into a cold water practice by ending your usual shower with 30 seconds of cool water and gradually extending this time to two to five minutes as your body adapts.
“There is no perfect temperature or duration,” she says. “The key is to find a safe area that is uncomfortable but tolerable for you.”
