UNLESS YOU HAVE the free time to hit the gym more than once a day, if you’re including weight training and cardio in your programming, you’re combining them in one massive block. So, which should you do first: cardio or weights?

It’s almost surprising we’ve progressed to a place where guys are asking this question. Gym wisdom long held that cardio can hurt your gains, and building muscle would inhibit cardiovascular performance. More recent research has shown us that cardiovascular exercise can help with muscle gains, and muscle gains can help with cardiovascular performance. A study published in the Journal of Gerontology found that long-term aerobic exercise is associated with greater muscle strength throughout a lifespan. Now, you’ll find the highest level endurance runners, swimmers, and bikers in the weight room a few times a week—lifting weights can even help such athletes improve VO2 max, according to University of Oklahoma researchers. You’ll also find the strongest powerlifters and bodybuilders hitting the cardio floor (if only to walk on the treadmill).

Plus, both cardio and weight training promote different aspects of health—both needed for overall well-being. A 2022 British Journal of Sports Medicine study found that those with regimens that included both cardio and weight training had a lower risk of mortality than those who only did cardio. The focus has shifted away from which style of training you should be doing, to how to incorporate the two together effectively based on your goals.

Here, experts explain whether you should do cardio or weight training first in your workout, depending on your goals.

How to Decide Between Cardio Before or After Weights

If you were to poll personal trainers about the questions they receive most often, there’s one that would occur on almost every list: What should I do first during a workout: lifting or cardio?

It’s a loaded question, and the full answer depends on a number of factors, including your fitness level, exercise experience, athletic goals, and how much time you can devote each day to working out. It’s also somewhat of a false dilemma, as there are a number of ways to perform strength training and cardio simultaneously, such as high-intensity interval training (HIIT) and circuit training. But if you have general fitness goals, you want to approach cardio and strength training separately in the same workout, and you’re looking for a general rule, here it is: Lift first, then do cardio second. If you’re looking to split your training into a two-a-day workout split, follow these tips to optimize your efforts.

Why Weights Should Come Before Cardio

The reason is that strength training typically involves external loading (e.g., with a barbell, dumbbells, kettlebells, resistance bands, etc.), and thus has a more acute injury risk. Pre-fatiguing your muscles with cardio prior to lifting weights will only elevate that risk—not to mention torpedo weightlifting performance. In short, you won’t be able to lift as much or perform as many reps as you would if you started with your strength training.

If you plan on lifting heavy, you need your muscles to be fresh in order to do so with good form and to load them sufficiently to optimize their growth stimulus. You simply can’t do that if you “pre-fatigue” your muscles with cardio.

What If I Want to Improve Cardiovascular Endurance?

Of course, there’s also the counter argument: If you lift weights before doing cardio, won’t that inhibit your aerobic performance? The answer is yes. Research suggests that you’ll likely notice a reduction in power, speed, and stamina, providing yet more incentive to perform strength training and cardio on different days.

But what lifting weights prior to performing aerobic exercise won’t do is significantly increase your risk of injury—and that’s a key difference to keep in mind when designing your workouts and programing your training plan. Try to tailor your aerobic training and your weight training on different days to optimize both. But, if you do have to do your weight training and cardio on the same day, stick with weights first.

Exceptions to the Weights Before Cardio Rule

As with all things in life, some rules are meant to be broken, and the “lift first, do cardio second” decree is no different. Here are a couple of instances when you should flip the script.

Warming Up

Working out without warming up is like driving a car in winter without letting it idle first—you’re going to strain your engine or (at the very least) compromise its performance.

Warming up with a bit of light cardio prior to any workout—whether it be strength or cardio based—will help prime your muscles for action. You’ll increase blood flow throughout your body, excite your nervous system, and increase your mental focus, which will all get you primed for a great sweat session.

HIIT and Circuit Training

There are also times when it’s appropriate to combine strength training and cardio in the same workout. HIIT and circuit training are two of them. Protocols that get you moving like EMOM and AMRAP are two more. The basic idea is this: By prioritizing work efforts and minimizing rest periods, you keep your heart rate elevated and metabolism cranking while challenging your muscles and stimulating hypertrophy.

In short, you get the best of both worlds—the calorie-burning and endurance-boosting benefits of cardiovascular conditioning and the muscle-building and power-developing rewards of strength training.

But here’s the thing: You shouldn’t do these high intensity cardio workouts every day. In fact, you should only perform it two to three times per week (at most), because if you do it more often, your body won’t have time to recover sufficiently between sessions. So what should you do on the other days? You guessed it—strength training and/or lower intensity cardio.

Trevor Thieme is a Los Angeles-based writer and strength coach, and a former fitness editor at Men’s Health. When not helping others get in shape, he splits his time between surfing, skiing, hiking, mountain biking, and trying to keep up with his seven year-old daughter.

Cori Ritchey, NASM-CPT is an Associate Health & Fitness Editor at Men’s Health and a certified personal trainer and group fitness instructor. You can find more of her work in HealthCentral, Livestrong, Self, and others.