Hot vs. Cold Exposure: Which Is Better for Muscle Recovery?

When it comes to building muscle, maximizing your recovery is a crucial step. And some of the best ways to do that have also been around for centuries: saunas and cold plunges. But is there one temperature extreme that helps muscles more efficiently than the other? The answer is nuanced, according to the experts we consulted.Before even considering an ice bath or sauna, though, make sure you have the basics sorted in your warm-ups and cool-downs, which are also very importing for preventing injury and improving muscle growth. Once you have those down, here's how vs. cold exposure shakes out.Benefits of cold therapy for muscle recoveryThere's a lot to be said for a bag of frozen peas. In the same way it can help a rolled ankle, cold therapy—or cryotherapy to use the fancier term—is a handy way to alleviate extreme pain and microtears caused by working out.“Cold therapy plays a critical role in reducing inflammation and swelling in muscles and joints,” says Sergii Putsov, Olympic weightlifter and Head of Sports Science at Torokhtiy Weightlifting. “Its numbing effect can provide instant relief from muscle soreness and pain. Since it constricts blood vessels, cold therapy helps flush out waste products such as lactic acid from muscles.”Read MoreInside the Sauna OlympicsAt the Aufguss World Masters, spa enthusiasts twirl towels in saunas to distribute heat, scent, and showmanship. A New York City bathhouse founder leads us through the sport’s biggest week–and explains why it’s coming to an American spa near you.Jumping in an ice bath is particularly good after a cardio session. “It's beneficial immediately after workouts to reduce inflammation and muscle soreness,” says George Thomas from Tennis HQ, “[and] is particularly effective post-cardio to reduce muscle soreness and inflammation.”While Steven Dick, director at The Fitness Group, adds that “cold therapy is particularly beneficial for preventing further tissue damage,” it's also been shown to help in various aspects of your health, including an uplift in mood. Getting the most out of cold therapy can be as simple as jumping in the bath or using ice packs: Putsov suggests submerging your body in water at 10-15 degrees Celsius (50-59 Fahrenheit). Be aware that cold water can give you a shock, so take a more gradual approach if you have an underlying heart issue or respiratory condition such as asthma— and don't sit in the ice for longer than 10 minutes.All that said, it should be noted that recent research shows that consistently plunging after a lifting session can limit muscle gain—crucial to keep in mind if you're trying to get swole.Benefits of heat therapy for muscle recovery“Hot therapy relaxes muscles and improves flexibility,” says Pustov. “It also increases blood flow since it heats and dilates blood vessels. Enhanced blood flow delivers more oxygen and nutrients to your body muscles, accelerating recovery. Furthermore, heat therapy can help reduce muscle stiffness and tension, making it easy to recover from strenuous workouts.”Gregor Parella, fitness consultant at Ringside24, also sees heat as the perfect way to recover from strength training. “Heat therapy helps in quickly recovering from hypertrophic (muscle-building) workouts,” he says. “It reduces delayed-onset muscle soreness and improves glycogen replenishment and protein synthesis.” A half an hour stint in the sauna or a long soak in a hot bath is usually enough to feel the benefits come your next workout.In fact, it might even be worth heating up before warming up. “Heat therapy is most beneficial before workouts to warm up muscles, enhance blood flow, and prevent injuries,” says Thomas. “Heat therapy is especially useful before cardio and strength training sessions to prepare muscles, reduce the risk of strains, and ensure muscles are warm and flexible.”Hot vs cold: which is better for muscle recovery?The answer is a bit of both, usually known as contrast therapy, so it makes sense that both should form part of your recovery routine.“The old Nordic cycle, which is what most people go by, says you should always have a sauna first before going for an ice bath plunge,” says Martin Sharp, coach and founder of Sharp Fit For Life. “The reason for this is that the sauna will increase blood flow and heart rate while relaxing your muscles. It's helpful after a workout to go into this relaxed state which starts the repair cycle.“Then you can go for the cold, whether that's a really cold shower or an ice bath. This will constrict your blood flow by reducing the size of your blood vessels and slows your heart rate down.”Ultimately, your body is a pretty good indicator of what works for you. “If you notice that heat provides better relief after a cardio session or cold helps more after strength training, it is worth adjusting your recovery routine accordingly,” says Parella. “The key is to listen to your body and to choose the method that helps you feel and perform at your best.”Timing is also important. “Hot therapy is only effective if administered immediately after exercise because heat is required to prevent elastic muscle damage,” says Putsov. And getting the balance of hot and cold right will hold you in good stead. As owner of ATT Evolution gym Tyron Woodley, who also happens to be a five-time UFC World Champion, concludes: “After your workout go into hot first, then cold. We call it contrast. This method has kept me in the game for this long.”A version of this story appeared in British GQ.