“Gaining muscle through resistance exercise means you can do more. You can work out harder and hike steeper trails,” sports dietitian Marie Spano, M.S., R.D., C.S.C.S., tells SELF. “This will lead to an increase in calories burned. Now, that’s significant.”
If you’re not concerned with how many calories you burn, then it’s still encouraging that strength training can improve your sports performance. (And again, there are countless benefits of exercise that have nothing to do with calories, weight, or metabolism.)
After a strength-training session, your metabolism stays elevated through a process called excess postexercise oxygen consumption (EPOC). But the effect isn’t huge.
EPOC is more commonly known as the afterburn effect. It refers to all of the oxygen (and energy, in the form of calories) that your body takes in and uses after exercise to help repair your muscles and recover.
Research shows that strength training is especially effective at raising EPOC. That’s because, generally speaking, strength-training sessions cause more physiological stress to the body compared to cardiovascular exercise, even higher-intensity cardio intervals. However, it’s worth noting that overall exercise intensity is what makes the biggest impact on EPOC. So squats, deadlifts, and bench presses with heavy weights are going to be much more effective at raising EPOC compared to bicep curls and triceps extensions with light weights.
How much of a difference does EPOC make? Well, in one research study of young women, basal metabolic rate spiked by 4.2 percent 16 hours following a strength-training session that lasted an hour and 40 minutes—the equivalent of burning an extra 60 calories, on average. That’s a long workout, and 60 extra calories isn’t exactly huge. Plus, EPOC is not a permanent boost. Research suggests it may last anywhere from 12 hours to a few days, depending on the workout and who is doing it. The calories you burn through EPOC can add up over time, especially if you’re lifting weights three or four times a week, but all in all, it doesn’t have a very big effect on your metabolism.
In the end, the exact EPOC boost you get from your strength-training workouts depends on the exercises you perform, weights you use, reps and sets you perform, rest you take, and total time you spend sweating it out—not to mention your genetics and current fitness level and muscle mass.
As we age, we lose muscle mass, so strength training is essential for maintaining it—and a healthy metabolism.
Research shows that starting as early as age 30, the body begins to slowly lose muscle mass, with women losing up to 15 percent of their total-body muscle per decade by age 50. Apart from declines in strength, that declining muscle mass comes with a declining metabolism, Emilia Ravski, D.O., a sports medicine specialist with Hoag Orthopedic Institute in California, tells SELF. This decline in metabolic rate is actually one driving factor of the weight that women generally tend to put on after we naturally hit our peak muscle levels in our 20s, research from Tufts University suggests.
However, through a targeted total-body strength-training program, it’s possible to not only prevent muscle loss, but actually increase your muscle mass (and keep your metabolism up) throughout your life.
In other words, while strength training might not increase your metabolism very much, it can help you maintain your metabolism as you age.
The best way to build muscle mass and get the biggest metabolic boost: Perform compound movements and lift heavy.
If you want to train to build muscle mass, focus on integrating at least three strength-training workouts into your weekly exercise routine and prioritizing large, compound movements—which require multiple muscle groups to work at once—over small, isolation exercises.