Cold plunging is exploding in popularity, which means the myths are exploding too. Social media is full of extreme claims, miracle testimonials, and oversimplified advice that makes it hard to know what is real and what is hype.
As the founder of FjØRD Cold Plunge, I hear these misconceptions every week. Some of them discourage people from starting a practice that could genuinely change their health. Others set unrealistic expectations that lead to disappointment. Both are problems.
Below, we break down the most common cold plunge myths, pair each one with what the peer-reviewed research actually says, and help you build a practice based on facts rather than internet folklore.
Myth 1: “Cold Plunges Melt Fat While You Sleep”
The myth: Cold plunging activates brown fat, supercharges your metabolism, and burns significant body fat without changing your diet or exercise habits.
The fact: Cold exposure does activate brown adipose tissue (BAT) and can slightly increase energy expenditure, but the effect on body weight is modest at best. Nutrition and physical activity still do roughly 95 percent of the work.
A 2021 study published in Cell Reports Medicine found that habitual winter swimmers showed enhanced cold-induced thermogenesis compared to controls, suggesting that regular cold exposure can train the body to burn more energy in response to cold (Søberg et al., 2021). However, the caloric impact of this increased thermogenesis is relatively small in the context of total daily energy expenditure.
A narrative review in PMC examining the effects of intermittent cold exposure on adipose tissue confirmed that while cold exposure can promote the browning of white fat and improve metabolic markers like glucose tolerance and insulin sensitivity, it does not consistently reduce body weight or fat mass in humans (PMC, 2024). In mouse studies, food intake increased to fully compensate for the additional energy burned during cold exposure (Ravussin et al., 2014).
The bottom line: Cold plunging can support better metabolic health, improve insulin sensitivity, and complement a solid nutrition and training plan. But it is not a fat-loss shortcut. If you are interested in the full science behind cold exposure and metabolism, we covered it in detail on the FjØRD blog: The Impact of Cold Plunging on Testosterone, Fat Burning, and Blood Pressure.
Myth 2: “If You Are Not at 39°F, It Does Not Count”
The myth: You need to plunge at the coldest possible temperature (often cited as 39°F or lower) or you are wasting your time.
The fact: Many people get significant benefits in the 48°F to 55°F range. The stimulus matters, but so does repeatability. A temperature that scares you out of the tub every other day is worse than a slightly warmer temperature that you actually use consistently.
Research on the neurochemical response to cold water immersion shows that meaningful increases in dopamine and norepinephrine occur at temperatures well above the extreme end. Šrámek et al. (2000) observed a 250% increase in dopamine and a 530% increase in norepinephrine at 14°C (57°F), and longer-term studies have shown that regular cold immersion at moderate temperatures still produces significant norepinephrine adaptation over 12 weeks (Šrámek et al., 2000).
The first comprehensive PLOS ONE meta-analysis on cold water immersion and health (2025) included studies with temperatures ranging from 7°C to 15°C (approximately 45°F to 59°F) and found positive effects on mood, stress, and wellbeing across that range (Cain et al., 2025).
The bottom line: Start at a temperature that challenges you but does not paralyze you. Many experienced plungers settle into a daily practice between 45°F and 55°F. If you want to go colder over time, the FjØRD Lux chills down to 36°F, so you have room to progress. But the most effective temperature is the one that keeps you coming back. We break down how to find your ideal range in our guide to designing your own cold plunge protocol.
Myth 3: “Cold Plunges Are Dangerous for Everyone With a Heart Condition”
The myth: If you have any cardiovascular concern whatsoever, cold plunging is off limits.
The fact: Cold water immersion is a serious physiological stimulus and should be approached with caution, especially by those with cardiovascular conditions. But a blanket ban is an oversimplification. With proper medical guidance, many people with cardiac concerns can use controlled cold exposure safely.
The cold shock response triggers an acute increase in heart rate and blood pressure, which can pose a genuine risk for individuals with unmanaged hypertension or arrhythmias. This is real and should not be dismissed (PMC, Knechtle et al., 2025). However, the same review notes that cold water therapy has been used safely in numerous clinical populations when exposure is gradual, controlled, and supervised.
Research on sauna bathing (often paired with cold plunging in contrast therapy protocols) has actually shown cardiovascular protective effects. The landmark Finnish study by Laukkanen et al. (2015) found that frequent sauna use, which involves significant cardiovascular stress through heat exposure, was associated with reduced risk of fatal cardiovascular events over a 20-year follow-up (Laukkanen et al., 2015). While this does not directly prove that cold plunging is safe for heart patients, it illustrates that controlled thermal stress, when applied appropriately, can have a protective rather than harmful effect on cardiovascular health.
The bottom line: If you have a heart condition, blood pressure concerns, or any medical history that gives you pause, talk to your doctor before starting a cold plunge practice. Do not take medical advice from social media. But do not assume cold exposure is categorically off limits either. Many people with cardiac concerns use cold water immersion safely with proper guidance, gradual acclimation, and equipment that offers precise temperature control like the FjØRD cold plunge systems.
Myth 4: “If I Miss a Day, I Lost All My Momentum”
The myth: Cold plunging only works if you do it every single day without exception. Miss a day and your progress resets.
The fact: This is a lifetime practice, not a 30-day challenge. Missing a day, or even a week, is not failure. Coming back is the skill.
The research on cold water immersion consistently shows that benefits accumulate with repeated exposure over time, but there is no evidence that occasional breaks erase prior adaptation. In fact, the concept of hormesis, where moderate, intermittent stress improves the body’s capacity to handle future stress, inherently involves periods of recovery between exposures (Kopplin & Rosenthal, 2022).
The 2025 PLOS ONE meta-analysis reviewed studies with cold water immersion protocols ranging from single sessions to multi-week regimens, and beneficial effects on mood and wellbeing were observed across varied frequencies (Cain et al., 2025). What mattered was sustained engagement over time, not perfection on any given day.
The bottom line: The goal is consistency, not perfection. Two to four plunges per week is a strong starting point for most people. If you miss a few days, the water is still cold and your body still knows what to do. This is one reason a dedicated cold plunge system matters so much. When the water is always cold, always clean, and always ready, coming back after a break takes zero setup and zero willpower. You just step in.
A Few More Myths Worth Addressing Quickly
“You need to stay in for 10+ minutes to get benefits.” Not true. Research shows meaningful neurochemical and mood responses from immersions as short as one to three minutes at appropriately cold temperatures. Longer is not always better, especially when you are building a new habit (Šrámek et al., 2000).
“Ice baths and cold plunges are the same thing.” They are not. An ice bath is a one-off setup with ice and a tub. A cold plunge is a dedicated system with a chiller, filtration, and precise temperature control built for daily use. We covered this in full in our guide to cold plunge vs ice bath vs contrast therapy.
“Cold plunging replaces exercise.” It does not. Cold exposure is a powerful complement to training, not a substitute for it. A systematic review of cold water immersion for athletic recovery confirms that CWI supports recovery between sessions, but the training itself is what drives adaptation and performance.
What Cold Plunging Actually Does (and Why That Is Enough)
Cold plunging does not make you a superhero. It does not melt fat while you sleep, cure diseases, or exempt you from doing the other hard work of a healthy life. But here is what it does do, backed by growing scientific evidence: it elevates dopamine and norepinephrine for hours after a session. It can reduce inflammation and support immune function. It trains your nervous system to stay calm under pressure. It builds a daily practice of choosing discomfort on purpose, which changes how you show up for everything else.
As a builder, I love the hardware. As a human, I love what happens when people use that hardware to challenge their beliefs about what they are capable of. Cold does not give you something new. It shows you there was more in you the whole time.
If you are ready to start a practice built on facts, not myths, explore the full FjØRD Cold Plunge lineup. Every tub is American-made, precision-engineered, and designed to be the backbone of a daily ritual that actually sticks.
References
Søberg, S., et al. (2021). Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine, 2(10), 100408. PubMed
PMC (2024). The effects of intermittent cold exposure on adipose tissue. Full Article
Ravussin, Y., et al. (2014). Effect of intermittent cold exposure on brown fat activation, obesity, and energy homeostasis in mice. PLOS ONE. PMC
Šrámek, P., et al. (2000). Human physiological responses to immersion into water of different temperatures. European Journal of Applied Physiology, 81(5), 436–442. PubMed
Cain, T., et al. (2025). Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis. PLOS ONE. Full Article
Kopplin, C. S., & Rosenthal, L. (2022). The positive effects of combined breathing techniques and cold exposure on perceived stress. Current Psychology, 42, 27058–27070. PubMed
Laukkanen, T., et al. (2015). Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine, 175(4), 542–548. PubMed
Knechtle, B., et al. (2025). The untapped potential of cold water therapy as part of a lifestyle intervention for promoting healthy aging. PMC. Full Article
Cold Water Immersion for Mental Health and Stress Resilience