It’s difficult to scroll through social media without seeing an influencer or celebrity rave about cold plunges — aka soaking in ice-cold water.
Although cold plunges may be the wellness trend of the moment, there is still something to be said for the other water therapy: the hot tub. In fact, new research spotlights the benefits of taking a steamy soak and shows how it compares to the brisker alternative.
What does the study say?
The study, which is being presented at the Integrative Physiology of Exercise conference, has young adult male athletes perform 50 minutes of high-intensity interval running prior to soaking in a cold-water tub (at 59 degrees Fahrenheit), soaking in hot water (at 104 degrees Fahrenheit), or just sitting without being in any water.
Researchers measured changes in proteins and enzymes that can indicate muscle damage and the participants’ ability to jump high. Volunteers were asked to rate how sore their muscles felt.
Researchers discovered that participants had lower squat positions and jump heights with cold plunges than when they utilized the hot tubs. The two soaking methods showed no significant differences in myoglobin and creatine kinase levels.
As a result, researchers concluded the hot tub was better than cold plunging for exercise performance. However, they also found that a cold plunge is more effective at easing inflammation, fatigue, and swelling from exercise. Overall, one wasn’t better than the other — they were only different.
So, when should you do a cold plunge, and when is a hot soak better?
What exactly is a cold plunge, and what are its benefits?
A cold plunge is a type of cold therapy during which you totally or partially immerse yourself in water that’s colder than 60 degrees Fahrenheit for a short period, said Dr. Joseph J. Ciotola, an orthopedic surgeon at Baltimore’s Mercy Medical Center. Ciotola and Wim Hof — extreme athlete and cold plunge expert — studied.
“It has been suggested that cold plunges can help with increasing mood, [providing] pain relief from workouts, lowering inflammation or activating the parasympathetic nervous system and minimizing stress responses,” said associate professor in the Department of Kinesiology and Health at Rutgers Robert Wood Johnson Medical School, Steven K. Malin. “Some have even suggested improvements in health by way of better insulin sensitivity and blood pressure.” However, Malin stresses, “this evidence is highly mixed.”
There may be some positives of cold plunging, “but very little research has confirmed the advantages,” said primary care sports medicine specialist at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles and team physical for Angel City Football Club and LA Galaxy, Dr. Tracy Zaslow. Zaslow says it isn’t clear why cold plunging may help people. “Maybe it’s changes in adrenaline or cortisol — or even dopamine.”
One analysis of preexisting studies published last year discovered that cold water therapy helps with soreness following exercise. Another study found that cold plunges may also help lower the body’s inflammation. However, Zaslow says additional research must be done.
What are the risks?
Cold plunging is an intense activity, and there are some risks that should be considered. Malin says there are worries that individuals with cardiac conditions could experience possible vascular or heart issues in response.
“But even if they do not have preexisting issues, the cold immersion under 60 degrees may raise breathing rate, heart rate, and blood pressure — and promote drowning,” says Malin. “This is in part due to blood rushing away from arms and legs to the core of the body to keep the heart able to pump blood.” Hypothermia — abnormally low blood temperature — is also a concern.
“If done carefully, there are very little to no risks,” says Ciotola. “The biggest risk is staying in too long. Two minutes is all you need to get the benefit.”
What is hot water immersion, and what are the benefits?
Hot water immersion, also called hot water therapy, involves partially or fully immersing yourself in hot water (for example, by sitting in a hot tub). “It’s used more for muscle relaxation and spasms,” says Ciotola.
Research has discovered hot water therapy may help you perform better athletically. A 2020 study had athletes sit up to their necks in 102-degree water for 30 minutes immediately following a training session three times weekly. At the end of three weeks, researchers discovered the participants had a 3.2% improvement in their bodies’ efficiency in using oxygen and up to an improvement threefold in the amount of oxygen their bodies needed to do a workout.
Research has also linked hot water therapy to improved muscle relaxation, lower levels of stress, and even a lower risk of developing cardiovascular disease.
What are the risks?
There are a few things to consider with hot water immersion. “Hot water, like cold water, can be uncomfortable and promote burns,” says Malin. Temperature in many studies tends to be near 104 degrees Fahrenheit, but going well above that should be used with caution to minimize risks.”
Malin says you can also develop dizziness, dehydration, headaches, and lightheadedness from overdoing hot water immersion.
When should you choose one over the other?
It’s crucial to point out that you don’t have to do hot water immersion or cold plunges if they don’t appeal to you (or if you don’t have access to either option). Malin emphasizes that additional data is necessary to assess both therapies.
When it comes to overall fitness, Malin notes that exercise itself is still the best way to go. “This should be the focal point,” he states. Given the mixed evidence in the literature, ‘supplementing’ with hot or cold tub exposure could have subtle potential benefits,” says Malin. Ciotola additionally stresses that both of these practices have “different functions.”
If you have access to a hot tub and cold plunge, Malin recommends trying both and seeing how you feel. “It might be that both are ultimately needed to target some of the different benefits,” says Ciotola. Or they just might make you feel great. Either way, science doesn’t definitively say one is better than the other.
