The answer depends on what you hope to get out of your workout.
Where do you head first when you get to the gym: the treadmill or the weight rack? Chances are, you prefer one over the other—and we’re guessing it’s the treadmill.
But there are times you might want to add strength training into your workout. And while deciding which one to start with may seem like no big deal, your choice can actually impact your fitness goals.
First, you need to think about what your end game is: Are you aiming to improve your cardio fitness, looking to build strength, or trying to lose weight? That’s going to determine your workout sequence and how often you should be doing cardio and weight training, especially if you’re going to double up on the same day. Here’s what the experts have to say about how to prioritize.
Is it better to do cardio before or after weights?
If you’re looking to build strength, do cardio after weight training. The reason is pretty simple: Lifting is hard, and you need all the energy (physically and mentally) that you can get to properly lift heavy weights and avoid injury.
“If you prioritize weight lifting over cardio, you can focus more brain power on lifting those weights correctly versus going into a session sweaty and out of breath, unable to perform as well and upping your risk due to fatigue,” explains Eric Bowling, an NASM-certified personal trainer at Ultimate Performance in Los Angeles
The science backs him up: When researchers compared three workout protocols—strength training alone, running followed by strength, and cycling followed by strength—they found that running or cycling pre-strength workout limited the number of weight lifting reps that could perform compared to strength training without hitting a cardio machine beforehand. Another study found that muscle power decreased when lifting weights after running on a treadmill, while heart rate and the rate of perceived exertion, or how hard the workout felt, increased.
Weights should also come first if your main goal is weight loss. Doing cardio after weight training burned more fat during the first 15 minutes of that cardio workout versus starting with cardio and then lifting, according to a study published in Medicine and Science in Sports and Exercise.
[The best runners don’t just run, they hit the gym. The Beginner’s Guide to Strength Training will teach you all the fundamentals to get the most out of your weight session.]
Is it ever okay to start with cardio?
There’s nothing wrong with doing cardio before weight training, especially if you’re just generally trying to stay fit. And working up a sweat is a great way to prep your body for movement, so you may want to start your workout with cardio even if you are prioritizing weight training.
“Doing light cardio such as jogging or biking can prepare the muscles for the physical work of lifting weights and can increase blood flow to the large muscle groups you’ll be using,” explains Sarah Merrill, M.D., a primary care and sports medicine physician at UC San Diego Health Sciences.
And if your main goal is to improve your cardiovascular fitness, you should definitely start with cardio—for the same reason your should prioritize weight training if you’re looking to build strength. “Doing a heavy weight day before doing cardio may fatigue the muscles, causing you to lose proper form while you are doing cardio and increase the risk of injury,” says Merrill.
If you’re training for a race, doing weights before cardio could actually decrease your endurance. When a group of people performed strength training prior to running, they showed great running impairment (or decreases running economy) compared to the group that ran first, according to a study published in the journal Applied Physiology Nutrition and Metabolism.
Can you do cardio and weights on the same day?
Traditional workout guidance suggests people alternate their workouts—cardio one day, followed by weight training the next, or vice versa. But “there’s no reason you can’t do both in the same workout session, or split into two sessions on the same day,” says Mandeep Ghuman, M.D., director of Dignity Health Medical Group’s Sports Medicine Program in Northridge.
Take high-intensity workouts like CrossFit or Barry’s Bootcamp, which combine strength and cardiovascular training in one session to deliver results in a shorter time. Doing that type of workout doesn’t negatively affect you on any physiological level, according to a study published in the Journal of Strength and Conditioning Research—and it may be a much more efficient use of your limited time.
If you are going to do two separate workout sessions in one day, just make sure to leave enough time in between workouts for your body to recover—around eight hours between high-intensity cardio and lifting weights, says Bowling. Your body doesn’t physiologically adapt (i.e. get stronger, faster, develop more endurance) until after a workout, so continually stressing it with exercise will actually hinder your progress.
What’s the best type of cardio to combine with weight training?
Weight training is anaerobic exercise—basically, short bursts of energy that don’t require that you inhale additional oxygen. As a complement, “the best type of cardio to pair with weight training is low-intensity cardio,” says Bowling, which does require additional oxygen to keep your heart rate up over an extended period of time.
Any low-intensity aerobic activity—whether that’s swimming, using the elliptical machine, rowing, walking, running, or cycling—would work. The most important thing is to choose a kind of cardio you actually like to do.
“You’ll be more consistent with your workouts, which will make them more effective, if you’re enjoying the exercise,” says Merrill. “And it’s important to give your body some variety; always doing the same cardio or weight lifting regimen can cause fatigue or overuse syndromes in muscles and joints.”
“The more intense the cardio workout, the more time you’ll need to recover,” says Bowles.
FYI: If you’re training for an endurance sport, like a half marathon, you’re going to need to do higher-intensity cardio workouts. That’s fine, but make sure you have at least eight hours in between workouts to allow your body to recover and prime itself for lifting.
How often should you do cardio and weight training per week?
“The U.S. Department of Health and Human Services recommends adults have at least 150 minutes of moderate intensity cardio or 75 minutes per week of vigorous intensity cardio a week, and strength training at least twice a week,” says Merrill. But how you break that down depends on your goals—and your schedule.
“Ideally, I suggest weight training three times per week, as this frequency has been shown to be an effective strategy when it comes to muscle building and fat loss,” says Bowling. “Cardio can be done every day if it’s low-intensity; the higher the intensity, the less frequently you can perform it.”
In that case, your weekly schedule might look something like this, picking one cardio option:
- Weight training: 2–4 times per week
- Low-intensity cardio: 5–7 times per week
- Moderate intensity cardio: 3–4 times per week
- High intensity cardio: 1–3 times per week
How long those cardio workouts last depends, again, on your goals. If your goal is strength improvements, then you may want to limit your cardio to a 10- to 15-minute session to warm up your muscles,” says Ghuman. “If your goal is overall fitness and health then there is no real limit, except your physical and schedule limitations”—just keep those recommended weekly exercise guidelines in mind so you don’t overdo it.
Here’s a cheat sheet for whether you should do cardio before or after weights based on common fitness goals, according to the American Council on Exercise.
- If your goal is better endurance, do cardio first.
- If your goal is burning fat and losing weight, do strength training first.
- If you want to get stronger, do strength training first.
- On upper-body strength training days, you can do either first.
- On lower-body strength training days, lifts weights first.
- If your goal is just general fitness, do either first, but maybe start with the one you like less.