First, let’s look at why athletes take ice baths. The idea behind jumping into a tub of freezing water is that it will reduce swelling and inflammation, flush lactic acid from tired tissues, and redirect blood flow from the legs to the heart. All of that is thought to reduce strain on your ticker after a tough workout and speed up recovery, but the research is far from conclusive. Some studies have deemed ice baths ineffective at preventing delayed-onset muscle soreness, the pain that shows up a day or two after a hard training session. Others have shown that post-exercise ice baths can reduce strength and anaerobic performance directly after immersion.
Contrast water therapy, on the other hand, “doesn’t shut the body down” the way ice baths do, says Jamie Stanley, a researcher at the University of Queensland’s School of Human Movement Studies in Australia. This might make contrast water therapy a better choice if you need to train or compete again later in the same day; it’s been shown, just like ice baths, to decrease lactic acid concentration and reduce post-workout pain.
“If you’re training two times a day, contrast therapy is best after the first session while cold therapy is best at the end of the day,” Stanley says. How do you do contrast water therapy? In most studies, subjects alternated between hot water (99 to 109 degrees Fahrenheit) and cold water (54-59 degrees Fahrenheit) for about 15 minutes, spending three to four times longer in the hot water than in the cold water, and starting and ending the hydrotherapy session in cold water. For example, athletes would sit in cold water for a minute, then hot water for four minutes, alternating three times through for a total of 16 minutes, ending with a minute in cold water.
Contrast therapy may also be useful in “awakening the senses, making you more aware of what’s going on around you,” Stanley says, again making it a better choice when you need to recover quickly to get ready for another game or workout and aren’t ready to shut it down for the day.
But research into hydrotherapy has really just begun, leaving a lot of questions yet to be answered. Researchers are currently looking into whether or not it’s possible to use ice baths too often, potentially altering the body’s inflammatory response to exercise altogether. If that proves to be true, contrast water therapy may be a safer alternative recovery strategy.
For now, Stanley recommends periodizing the use of hydrotherapy as you would your training, saving ice baths and contrast water therapy for high volume blocks of training or intense workout sessions, or for the week leading up to a key race for which you want to feel completely recovered.
“Training once a day shouldn’t be a massive stress to recover from naturally for the typical age grouper,” Stanley says. In other words, those painful ice baths aren’t always needed.
THE BOTTOM LINE: Contrast water therapy, like ice baths, may speed recovery by helping to flush lactic acid from sore muscles, but both recovery methods should be used in moderation. If you’ve just finished a strenuous training session and are done for the day, an ice bath may be best for you. But if you plan to workout or compete again later in the same day, you might want to look into trying contrast water therapy.