Exposure to cold water is now hot. From influencers touting the mental health benefits of cold showers to professional athletes swearing by ice baths for recovery, it's become quite a health trend. Advocates say it can improve concentration, improve immunity and even reduce inflammation.
But researchers say the evidence, while intriguing, is mixed. Small studies suggest that short-term exposure to cold water, such as a cold shower, can improve alertness and mood, but other studies find minimal or short-term effects. Clearly, this practice triggers a cascade of physiological changes that can feel invigorating and, for some, therapeutic.
“When cold water hits your skin, your body experiences a cold shock response,” says Dr. Jonathan Leary, founder and CEO of Remedy Place, a health-based social club that offers guided cold immersions. “Essentially, this means increased breathing, a brief spike in heart rate and blood pressure, and a surge in stress hormones that make you feel awake.”
This type of cold exposure is associated with improved mood and reduced stress, but research is still ongoing, says Dr. Neha Pathak, an internal medicine and lifestyle medicine physician. “Several small studies show that exposure to cold causes the release of mood-enhancing neurotransmitters such as dopamine and norepinephrine, improving mood and concentration.” However, research in this area is “promising but not conclusive.”
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One analysis Research published in 2025 found that after about 12 hours of cold water immersion, people's stress levels decreased and sleep quality improved. AND Randomized trial 2015 More than 3,000 participants in the Netherlands found that when people finished a warm shower with 30 to 90 seconds of cold water, the number of sick days they took was reduced by almost 30% (though they were not sick any less). While this evidence is interesting, it hardly proves the power of cold showers.
“We still need high-quality studies on dosage—time, frequency, temperature—and long-term outcomes,” Pathak says. “It's reasonable to say that cold exposure may help, but that doesn't mean it absolutely does.”
Pouring cold water activates the sympathetic nervous system. This releases adrenaline and norepinephrine, hormones that temporarily increase heart rate, alertness, and circulation.
Research shows that this type of stress response also mobilizes certain immune cells that help fight infection. In short bursts, this can act as a wake-up call to your immune system.
2014 study found that people trained in cold exposure (such as cold water immersion) and breathing techniques could voluntarily influence their immune response. When given endotoxin (a substance that typically causes inflammation), those who practiced cold training produced less inflammation-controlling protein and experienced milder symptoms compared to a control group of people not trained in these techniques.
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Cold bathing can help perk you up, but it shouldn't be your only stress-relieving practice. “The immune response is thought to be directly related to stress reduction,” says Dr. Sirisha Wadali, a cardiologist at HonorHealth Women's Health Center in Arizona. “This is not a perfect solution, but rather a good incentive for already healthy habits.”
A cold shower is a controlled and rapid stimulation, while an ice bath is a full-body immersion that quickly lowers body temperature.
Cold showers are gentler and easier to control. They are generally safe for most healthy adults, are easy to incorporate into daily routine, and have a lower risk of shock, arrhythmia, and hypothermia.
Ice baths, on the other hand, are performed in very cold water, usually below 50°F (10°C). They cause the same physiological reactions, but more intensely.
Dr. Parth Bhavsar, a family medicine physician at Wellstar North Fulton Hospital in Georgia and a thermoregulation researcher, explains that both methods rely on cooling the skin, which causes blood vessels to constrict and release hormones.
“Ice baths cause a faster drop in body temperature and a higher adrenaline rush,” he says. “It also means a greater risk of irregular heart rhythms, hypothermia and what is called an ‘afterfall’, where your temperature continues to drop even after you leave the house.”
Cold showers are not for everyone. They can be dangerous for people with heart disease, high blood pressure or respiratory problems, Patak said. She advises checking with your doctor before trying them if you have heart disease, circulatory problems, Raynaud's syndrome, or are pregnant.
People with vascular disease—”especially those with circulation problems and uncontrolled high blood pressure,” says Wadali—should also avoid them, “as it can cause improper shunting of the blood.”
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However, for most healthy adults, exposure to cold water can be safe if done gradually. “Repeated exposure to cold trains the body to transition between ‘fight or flight’ and ‘rest and digest’ states,” says Pathak. “This physiological flexibility may also lead to greater emotional or psychological resilience.”
Consistency matters more than intensity. Experts suggest starting at 68-70°F and gradually lowering the temperature over time.
“About 50 to 60°F for one to three minutes is enough to reap cardiovascular benefits,” says Vadali. “Anything below 50 degrees for long periods of time should be avoided.”
Pathak recommends moving into a cold-water practice, ending your regular shower with 30 seconds of cool water and gradually increasing that time to two to five minutes as your body adapts.
“There is no ideal temperature or duration,” she says. “The main thing is to find a safe, uncomfortable, but tolerable zone for you.”
