Browse evidence-based analysis of health-related claims and assertions
What matters most for burning calories during weightlifting is whether you’re using big muscles like legs or small ones like chest—not how long you rest or how fast you lift.
Causal
You breathe the hardest not when you’re lifting, but right after you finish a set and are resting—your body is catching up on oxygen debt built up during the effort.
Descriptive
How long you rest between sets doesn’t usually change how long your body keeps burning calories after a workout—unless you do chest flys with long breaks, then it stops sooner.
Your body burns more calories after leg presses than after chest flys—even if you rest the same amount—because your legs use way more muscles and need more oxygen to recover.
Right after leg presses with only 1-minute breaks, your body gasps for air more intensely in the first minute than if you took 3-minute breaks—but this doesn’t happen with chest flys.
Whether you rest 1 minute or 3 minutes between sets, you burn about the same total calories—rest time doesn’t change your overall energy burn in these workouts.
After lifting heavy with your legs, your body keeps burning extra calories for about 40 minutes—but after doing chest flys with long breaks, it only lasts 20 minutes.
Doing leg presses burns way more calories than doing chest flys—even if you do the same number of reps—because your legs use more muscles and keep burning energy longer after you finish.
When doing leg presses, taking only 1 minute of rest between sets makes you breathe harder overall than taking 3 minutes, but this doesn’t happen when doing chest flys—your body handles short breaks better when using smaller muscles.
When you’re just starting out, how much total work you do matters more than how long you rest between sets—your muscles grow and get stronger either way.
Correlational
This study only looked at beginners doing one leg at a time, so we can’t say for sure if the same results would happen to experienced lifters or people training both legs together.
You don’t need long breaks between sets to get strong—just do the same total amount of work, even with short rests, and you’ll get just as strong.
The study used high-tech scans (MRI) to measure muscle growth in specific parts of the thigh, making the results more accurate than just guessing from body measurements.
If you take only 20 seconds between sets, you have to do way more sets to match the same total weight lifted as someone taking 2-minute breaks, making your workout longer and more intense.
The study didn’t find a difference between short and long rests, and even if there was a tiny difference, it’s too small to matter in real life.
Quantitative
By training only one leg at a time, the study made sure that things like overall tiredness or hormones didn’t mess up the comparison between short and long rest periods.
The strength gains from this study are about what you’d expect from regular weight training—whether you rest a little or a lot—so rest time doesn’t seem to change how much stronger you get.
Lifting weights that you can only do 10 times, pushing to failure, for 10 weeks makes your thigh muscles bigger and stronger—even if you rest only 20 seconds between sets.
By training both legs of the same person—one with short breaks, one with long breaks—the study made sure differences weren’t due to people being naturally different, making the results more reliable.
If you push yourself to the limit every set, whether you rest 20 seconds or 2 minutes, you’ll end up doing about the same total amount of work.
When people train just one leg with heavy weights, their thigh muscles get bigger and stronger—and this method works well for studying how different rest times affect muscle growth.
If you take only 20 seconds between sets, you can still lift the same total weight as someone taking 2 minutes—you just have to do more sets to make up for the shorter breaks.
If you lift heavy weights with either short or long breaks between sets—while doing the same total work—you’ll get about the same stronger in your leg muscles after 10 weeks.
Whether you take short or long breaks between leg exercises, as long as you do the same total number of reps, your inner and outer thigh muscles grow about the same.