We asked a doctor and experienced cold bathers what happens to the body in the first seconds of icy water and who might find this trend risky.
Cold showers, icy lakes, ice tubs in the backyard. On social media, you often see people willingly getting into cold water, pushing their limits, and after a few minutes, talking about the euphoria it brings. Terms like ice bathing or cold plunge have gradually moved from the world of cold-water enthusiasts to everyday people and have become part of modern wellness.
However, numerous claims about ice water sound too good to be risk-free. So, I looked at this topic not only through the eyes of people who've been doing it for years but also from a doctor's perspective—I wanted to know what really happens in the body when you enter cold water, where the benefits end, and where the risks begin.
It's Not for Everyone
According to Dr. Boris Bajer from Poliklinika Váš Lekár, the first contact with ice water is a huge shock for the body. “In the first seconds, due to adrenaline and later cortisol, the heart rate increases, blood vessels in the limbs constrict, and blood pressure rises,” he says. In other words—the body goes into alarm mode. That's why a cold plunge (immersing the body in very cold water) isn't suitable for everyone.
“The sudden temperature shock is risky because the cardiovascular system is subjected to extreme stress in seconds, which not every organism can safely handle,” notes Boris.
The risk concerns people with high blood pressure, arrhythmias, or ischemic heart disease. “Cold-water swimming is an extreme sport. You should consult your doctor before starting, ideally even a cardiologist,” recommends the doctor.
The Biggest Mistake?
According to Bajer, the difference between safe and risky cold-water exposure lies in one thing—gradual adaptation.“From a health perspective, gradual exposure is significantly safer than a sudden plunge into ice water,” emphasizes Boris.
Martin Thám, who has been teaching people how to work with cold for years, has the same experience. “The biggest challenge isn't the cold for most people, but managing the nervous system stress and keeping calm breathing. If you can’t do that, panic sets in, and you want to escape the water,” says Martin.
How to Safely Take a Plunge
According to the doctor and experienced cold-water swimmers, entering cold water safely follows clear rules:
- enter the water slowly, not by jumping
- go in for a few seconds and come out
- breathe through the nose and exhale slowly through the mouth
- avoid hyperventilating (fast breathing can be harmful)
- never do it alone
- warm up gradually after exiting, not with a hot shower
“I recommend beginners start with 30 to 60 seconds, submerged up to the shoulders. Advanced practitioners should not exceed 2 to 5 minutes. Longer doesn’t bring more benefits but higher risks of hypothermia,” says Boris. The ideal water temperature, according to the doctor, is between 0 and 15°C.
The Biggest Benefit? Surprisingly, It’s Not Physical
Bajer says something that might surprise many people: “Cold-water swimming isn't quite a cure-all. Its biggest confirmed effect is in mood improvement and building a stronger spirit. Immersing yourself in one-degree water for five minutes convinces the brain that we are stronger than we think.” This moment, according to Boris, explains why people return to cold water. Not for immunity, not for the heart, but for the feeling of achieving something unimaginable for most people.
Martin agrees: “The biggest benefit was stronger determination and overcoming obstacles. I started living more for myself and less out of fear.”
“I needed to cool down mostly ‘mentally’. During my divorce and the tense situation at home, cold-water swimming kept me afloat. I looked forward to clearing my head and cooling down.” says the spirited Katarína, who started swimming during a challenging divorce period.
What Keeps People Drawn to Cold Water
Michal describes his beginnings unassumingly. First, short cold showers at the end of bathing, a minute or two. Then came his first entry into a frozen lake—and according to him, he was instantly “hooked.” Today, it's his sixth season, and he goes to cold water two to three times a week, even if it means a half-hour drive. “In the first seconds, it’s mainly about the breath. The adrenaline is unbelievable,” he describes the moment that keeps bringing him back.
Other respondents share similar experiences. They even agree that since they started regularly swimming in cold water, illnesses have troubled them much less than before.
Risks People Don’t Realize
Bajer warns about the signs: “Dizziness, lightheadedness, arrhythmias, chest pain—then you need to get out of the water immediately.” He also points out something many are unaware of: “Cold plunging is counterproductive immediately after strength training. It suppresses muscle inflammation necessary for their growth.”
Women, Cycles, and Listening to Your Body
According to Bajer, cold water doesn’t harm hormonal balance directly, but influences it via stress hormones. “It’s not just about the menstrual cycle, but also sleep, stress, and fatigue.”
Katarína shares from her experience: “When I have my period and don’t feel like it, I don’t force it and just skip the plunge. When I feel good, I can last up to seven minutes. I listen to my body.” And that is the common thread of safe cold-water immersion.
