If you are concerned about how many calories you burn during strength training, chances are that you are actively trying to lose weight (or might want to ensure you are eating enough to support strength training without losing additional weight). Although strength training is challenging and requires a lot of hard work (especially when lifting heavy weights), it doesn't typically burn as many calories as cardiovascular (aerobic) exercises like running or cycling.
There is no simple formula for calculating calories burned during strength training because every strength-training workout is so different. You lift different weights with different muscle groups throughout a single workout, whereas during running, you use the same muscles in the same way for several continuous minutes. Some strength exercises, such as a barbell snatch, use more (and larger) muscles, while other exercises, like a biceps curl, may isolate a very small muscle. Obviously, the amount of energy (calories) used to execute these two different movements is very different. All we know is that a more challenging routine that uses full-body movements and large muscles (like the glutes and legs) will burn more calories than a strength-training workout that isolates small muscles.
While a heart rate monitor (HRM) can be used to calculate calories burned during aerobic workouts, the relationship between heart rate and calorie expenditure is not the same during a strength training workout, so whatever your heart rate monitor may tell you is likely inflated because it thinks you're doing cardio (not strength training). That's a short explanation for why a HRM isn't a good predictor of calories burned during strength training. For more depth on why using a HRM for weight training isn't such a good idea, click here.
So do we really know how many calories a person burns while pumping iron? According to this exercise list from Harvard Medical School, a general 30-minute strength training session burns an average of 90 calories (180 calories per hour) for a 125-pound person, 112 calories (224 calories per hour) for a 155-pound person and 133 calories (266 calories per hour) for a 185-pound person.
However, a January 2014 study from Arizona State University (reported by RunnersWorld.com) found that strength-based exercises like lunges, crunches and pull-ups might actually burn more calories than previously thought:
So how does this apply to you? How can you measure your strength-training calories burned? The truth is that there is no good way to do it. Even a rigorous strength-training routine, when you factor in rest periods, and time to set up and move between exercises, probably won't add up as much as regular cardio. But even if it might, there's simply no accurate way to tell. So if you want these numbers in order to calculate calories burned for weight loss, be conservative. It's better to underestimate how much you burn when lifting weights than to try to estimate on the high side. SparkPeople's free Fitness Tracker does offer estimated calorie burn levels for a variety of strength training exercises, and these estimates err on the conservative side based on intensity, exercise type, whether the workout was continuous or involved rest, and how complex the movements are.
Despite what is likely a low to moderate calorie burn, strength training shouldn't be neglected—especially during weight loss. When losing weight, you will lose some muscle mass along with body fat. If you don't perform resistance training regularly, up to 30% of the weight you lose can come from muscle tissue, which doesn't do your health, fitness or metabolism any favors in the long run. Strength and muscle mass are essential for overall health and daily functioning. Need more reasons to pick up a pair of weights and start lifting? Learn more about the benefits of a regular strength program.
Want one more reason to pick up the weights? Strength training boosts your metabolism, helping you burn more calories long after a workout is over. According to one study published in the journal Medicine and Science in Sports and Exercise, an intense 45-minute exercise session (cardio or strength training) boosted participant's post-exercise calorie burn for 14 hours after the workout was over. This isn't something you can estimate or measure for tracking purposes, but it is a nice bonus for your efforts!
Keep in mind that all information about calories burned (whether from SparkPeople's database or another site) is based on estimates. When setting expectations for weight loss, remember that progress doesn't always happen in the consistent manner you might expect. Focus on the bigger picture and all of the health benefits that regular strength training provides!
How do you track your strength-training workouts? Do you try to estimate calories burned?
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