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When it comes to setting fitness goals, chances are you’re going to need to do cardio or strength training to achieve them—and most likely, you'll have to do both. After all, this combo can make you stronger, improve your bone density, and help you lose fat while gaining muscle. But when it comes to the order in which you do ’em, which is better: cardio before or after weights? Deciding which one to start with may seem like NBD, but that choice can actually impact your fitness goals.
First, you need to think about what your end game is: Are you aiming to make your heart and lungs healthier or get stronger? Perhaps you’re more interested in weight loss or weight management. Your priorities are going to determine your workout sequence and how often you should be doing cardio or lifting weights.
Here’s a cheat sheet 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.
But if you really want to understand why it’s better to do cardio before or after weights, depending on your fitness goals, read on for all the deets.
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 move loads with proper form and technique 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, CPT, a 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 treadmill or exercise bike beforehand, per a study published in The Journal of Strength and Conditioning Research (JSCR).
What’s more: 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, according to another JSCR study.
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.
And if you’re focused on a specific heart health goal like reducing heart fat, weights win again. Compared to aerobic exercise, resistance training was found more likely to reduce a type of heart fat that has been linked to cardiovascular disease, according to a 2019 JAMA Cardiology study.
But there’s nothing wrong with doing cardio before weight training, especially if you're just generally trying to stay fit.
Revving your heart rate 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, MD, a primary care and sports medicine physician at UC San Diego Health Sciences.
You should aim to add 10 minutes of low-impact cardio such as this to your warm-up, according to the National Academy of Sports Medicine (NASM).
And if your main goal is to improve your cardiovascular fitness, you should def start with cardio.
The same logic that says you should prioritize weight training if you’re looking to build strength applies here, too. “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 Dr. 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, MD, director of Dignity Health Medical Group’s Sports Medicine Program in Northridge.
Take high-intensity workouts like an at-home CrossFit or Barry’s Bootcamp session, 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 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 high-intensity effort that isn't fueled by oxygen. As a complement, “the best type of cardio to pair with weight training is low-intensity cardio,” says Bowling, which is fueled by oxygen consumption.
Any low-intensity aerobic activity—whether that’s swimming, using the elliptical machine, rowing, walking, jogging, 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 Dr. 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.”
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 Dr. 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 Dr. 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 overtrain.