Those Ice Baths May Not Be 'a Great Idea'

If you've ever been tempted to buy an ice bath or take part in a "polar plunge," you may want to check out this study first—at least if you're into weight training. A dip into frigid waters "looks like it's not a great idea" if your main focus is your muscles, Maastricht University's Milan Betz, lead author of a new study on the matter, tells the Washington Post.

• For the admittedly small study recently published in the Medicine & Science in Sports & Exercise journal, researchers had 12 healthy young men take part in a rigorous session of leg presses and leg extension exercises before being made to use a bike-like device in which one of their legs was submerged in a container of 80-degree water, while the other was placed in a container of freezing 30-degree water.

• After staying in that position for 20 minutes, the subjects then consumed a recovery shake with protein molecules that could be traced in the subjects' blood flow. What the scientists found is that blood flow in the colder leg fell a notable amount after the workout, and that the muscles in that leg didn't absorb the shake's proteins as well as those in the other, warmer leg—which, over time, "would likely mean blunted gains in strength and muscle mass from the lifting," per the Post.
• Another researcher not involved in the study, University of Sherbrooke health sciences professor Denis Blondin, says that perhaps the timing of the ice bath—as well as how deep the person is submerged, the water's temperature, and how long the person soaks for—could be tweaked to prevent the muscle shrinkage.
• This study didn't look at how cold plunges affect recovery from other sports, nor did it include older subjects or women, though Betz anticipates that studies that did would produce similar results. Earlier this year, Women's Health looked more closely at the female angle, and while studies on that are still scarce, one cold-exposure therapist notes that "physiological differences between genders may influence individual responses to cold exposure."
• In the meantime, Betz says that, despite the discouraging news on muscle recovery, the psychological outcomes of such chilly dips—for example, feeling mentally strong and resilient—may also mean "there's no reason to change your mind" if you enjoy them.