I first noticed the sauna-and-cold-plunge combo becoming popular about a year ago, when an invitation to try a Manhattan bathhouse hit my work inbox. Then another arrived, and another, and another, and another. Suddenly, everyone I knew (not to mention the athletes I interviewed) was marinating in their own sweat and then submerging themselves in icy water as a form of self-care, paying a premium to toggle between overheating and freezing.
This custom—exposing your body to alternating temperature extremes for supposed health benefits like faster workout recovery, increased mental clarity, and a higher metabolic rate—is formally known as contrast therapy. While contrast therapy has long been popular in Scandinavia, it’s only recently infiltrated mainstream US culture, especially in big cities like New York and Los Angeles. Riding the wave of the larger wellness movement, sauna chains like Othership and Lore Bathing Club have opened locations in the Big Apple. Even national gyms—like LA Fitness, EoS Fitness, and Crunch Fitness—are starting to install sauna facilities, Tyler McDonald, NASM-CPT, CNC, a certified personal trainer specializing in tennis and a senior brand marketing manager for the National Academy of Sports Medicine, tells SELF.
When I visited Othership, I found the experience invigorating, as promised, but I also wondered about the science of it all. Was there any research to support the myriad health claims floating around? To find out, I spoke with a few experts in the fitness space. Read on to learn whether contrast therapy is legit, and how to practice it for best results.
How does contrast therapy work?
In the fitness world, contrast therapy is a workout recovery modality designed to help pro athletes and everyday exercisers bounce back faster after a tough bout, according to McDonald. Generally, a routine consists of “10 to 15 minutes in the heat of the sauna, and then two to three minutes in the cold of the ice bath,” he says. “This does two things: The cold really reduces the inflammation, and then the heat increases the circulation and tissue elasticity of your muscles.”
Blood vessels expand and contract to allow more or less blood to flow through to vital organs like the heart. By triggering that expansion and contraction, contrast therapy essentially functions as “a vascular pump,” McDonald says. (In this sense, it has a similar effect to another popular recovery technique—compression therapy. In fact, the two are effectively different sides of the same coin, according to McDonald.)
How contrast therapy can improve athletic performance
Let’s start with the heat. High temps trigger vasodilation—the technical term for blood vessel expansion. “Your blood vessels are opening up, so you’re pumping more blood, which is allowing for a lot more blood to circulate throughout the entire body,” McDonald says. That, in turn, delivers oxygen “that helps repair the muscles you just damaged in the workout and builds those new tissues as you’re gaining strength or working out at a harder level.”