Cardio burns more calories than weight training, so you should do more cardio to lose weight, right? It’s true that unless you’re doing low-intensity cardio, you burn more calories doing during a cardio workout than you do lifting. How much of a difference is there? A person weighing 160 pounds burns around 250 calories in 30 minutes while jogging. If the same person lifted weights for that period of time, they would only burn around 115 calories. Cardio sounds like a no-brainer for losing weight but it’s more complicated than that.
Weight training, depending on how intensely you do it, burns more calories after the workout is over due to the after-burn effect, the extra energy your body has to expend to recover from a strenuous workout. Although the number of extra calories you burn post-workout is modest, you also build muscle which, over time, can subtly boost your resting metabolic rate. Weight training is like an investment in a faster metabolism. To get a substantial after-burn, you have to lift relatively heavy and work hard enough to work up a sweat. In contrast, jogging at a moderate pace doesn’t give a substantial after-burn and also does little to build metabolically active muscle tissue.
If you think from a longer-term perspective, weight training may ultimately benefit your body composition more. You’re getting stronger, improving your muscle to fat ratio, and building more metabolically active muscle.
This raises a second question. If you’re trying to lose weight, is it better to use heavier weights and lower reps or lighter weights and higher reps? Some people who are trying to lose weight reach for the lighter weights, do high reps and move quickly from exercise to exercise to keep their heart rate up. By limiting rest and keeping the heart rate high, they burn more calories. This approach also offers modest cardiovascular conditioning benefits. Yet, this isn’t ideal for building strength since you’re using light weights. Research suggests that you DO burn more calories when you do higher reps, at least during the workout itself. A study carried out by researchers at the College of New Jersey found that subjects boosted their calorie burn by 10% when they lifted using a resistance that allowed them to do 10 reps rather than 5.
At the other end of the spectrum, you could use heavy weights, 80% of your one-rep max, where you can do fewer reps. Using this approach, you burn fewer calories during the workout, but you get more of an after-burn effect due to the added stress you place on your muscles when you lift heavy weights. You also have to take into account the training volume. If you lift heavy and exhaust your muscles quickly and can only lift for 20 minutes, the overall calorie burn might still be lower than if you can do a 40- minute session using lighter weights, even when you take into the account the greater after-burn with the former. But an advantage here is you’re also building strength due to the heavier weights you’re using.
What’s the Best Approach?
All in all, it’s an issue of training volume versus training intensity. Using lighter and high weights, you can do a higher volume of training and burn more calories during the workout but lifting at a high intensity creates more of an after-burn and builds more metabolically active muscle tissue for long-term metabolic benefits. It also depends on your goals. If you’re trying to build strength as well as lose weight, using heavy weights and low reps make more sense.
Why not take advantage of both? Periodize your workouts so you’re doing blocks of high-rep, low-intensity training and somewhere you emphasize high-intensity, low-rep training.
Other Ways to Boost the Calorie Burn When You Weight Train
Now, let’s look at some other ways to burn more calories when you train with weights. You can subtly increase the calorie burn by how you structure your workout and the type of exercises you do.
Do a high ratio of compound to isolation exercises. Compound exercises that work more than one muscle group at a time burn more calories. In contrast, isolation exercises that work only one muscle group at a time burn fewer. Makes sense, doesn’t it? The more muscles you work simultaneously, the more energy those muscles require to contract. You also burn more calories working large muscle groups like the back and glutes than you do smaller muscles in the upper body. Therefore, the big calorie burners are exercises like deadlifts, squats, and pull-ups. You can boost the number of calories you burn during a weight-training session by including a high ratio of compound exercises to isolation exercises.
Also, add reciprocal supersets to your routine. A study published in The Journal of Strength and Conditioning Research found that reciprocal supersets increase the calories burned during a weight training workout. Reciprocal supersets are where you do two exercises back to back that work opposing muscle groups without resting between sets. In the study, reciprocal supersets relative to traditional weight training burned more calories during the workout and led to greater calorie burn after the workout. In fact, the afterburn was 33% higher in the hour after the workout.
Shorten the rest period between sets. You can spend a lot of time standing around between weight training sets. When you’re lifting to build strength, you need the extra rest to allow your muscles to recuperate enough to max out on the next set. That’s how you build strength – lift heavy. But if you’re trying to burn calories and fat, you don’t need the long rest periods. Shortening the rest periods between sets places more metabolic stress on your body and that helps boost fat loss. However, you also have to consider the fatigue factor. Lifting with short rest periods is fatiguing to the central nervous system.
The Bottom Line
Weight training is a long-term investment in creating muscle and subtly boosting your metabolism. So, don’t invest all of your time doing cardio based on the idea that it burns more calories. Also, don’t just do light weights and do high reps based on the idea that more reps and higher volume mean greater fat loss. Lifting at a high intensity, even if you do fewer reps, fires up your metabolism more after the workout is over. Why not strike a balance? Lifting heavy all the time can be exhausting to your nervous system and lifting light is more time consuming and is less effective for building strength. It’s a good argument for periodizing your workouts to include both!
Med Sci Sports Exerc. 2011 Aug;43(8):1575-81. doi: 10.1249/MSS.0b013e31821ece12.
The Journal of Strength and Conditioning Research, 24 (4), 1043–51.
IdeaFit.com. “Reciprocal Superset Training Burns More Calories”
The Journal of Strength & Conditioning Research, 26(7), 1817-1826.
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