Everybody has their own routine when they go to the gym. Some like to warm up by hitting their heart rate hard, breaking a sweat before making a move for the free weights. Others prefer to tackle strength first, leaving an intense cardio burner for last.
And while we’re all about you finding the gym rhythm that works best for you, it’s worth knowing that whatever activity you choose to do first can potentially impact your performance in that second activity.
According to an article published in the American College of Sports Medicine’s Health and Fitness Journal, which reviewed more than 20 relevant studies, you should structure your workouts according to your priorities. If you want to improve your heart health, conditioning, or endurance, start your workout with cardio. If you want to make strength gains, start with the weights.
Related: The Best Rep Range If You’re Strength-Training For Weight Loss
Whatever you do first will make you more tired than you would’ve been for what you do second—especially your legs, which are often used heavily in both cardio and strength exercise, according Nicholas Ratamess, Ph.D., C.S.C.S.*D, one of the authors and associate professor or Health and Exercise Science at The College of New Jersey.
If you want to hit cardio before a big lift, monitor your intensity. “If your cardio is low-intensity and short in duration, it may not have as many negative effects on your strength workout, for example,” he explains.
But if you’re attacking an intense cardio workout like HIIT (high-intensity interval training) right before lifting weights, expect your performance to be diminished, according to another one of Ratamess’ studies, published in The Journal of Strength and Conditioning Research.
The study had young, fit men perform intense running exercises, wait 10 minutes, and then perform a strength workout. The result: The participants who ran prior to lifting performed nine to 18 percent fewer reps than those who didn’t. Not surprisingly, the most dramatic difference was seen in leg exercises. The men also had higher heart rates, reduced power output, and higher overall ratings of fatigue.
Related: The Best Cardio Workout For Weight Loss
The good news: If your goal is to lose weight, both cardio and lifting will help you get there. “Both aerobic and resistance training increase your calorie burn,” says Ratamess. Aerobic exercise helps you burn more during exercise, while strength training will help you burn more after exercise.
Here’s how it works. Your muscles need to burn fuel to function, and part of that fuel comes in the form of oxygen. When you perform aerobic exercise, your muscles use oxygen at a rate that you can replenish with a little heavy breathing—that’s why you start to huff and puff when you jog or hit a quick round of burpees. But heavy lifting exercises (known as ‘anaerobic’) deplete your oxygen stores enough that you body has to work to replenish them long after you’re done exercising—burning extra calories the whole time.
The bottom line: Unless you’re training specifically for extreme cardiovascular performance or ultra-heavy weightlifting, how you order your workouts won’t have much impact on the benefits of breaking a sweat. However, you can still give sequential preference to one or the other if you’re training for specific goals (like wanting to become more muscular) or to improve certain weaknesses (like knee or ankle joint stability), according to Ratamess.
For most people, training both strength and cardio simultaneously can be a good long-term approach to fitness. Hence why what Ratamess calls “hybrid programs,” like CrossFit, Orangetheory, and Barry’s Bootcamp, have become so popular. In these types of fitness classes, you’ll bounce back and forth between cardio efforts like running or rowing and strength exercises like pushups or squats. The workouts require both cardiovascular capacity and strength, and create more of a hybrid athlete instead of a specialist, he says.