Top strength and conditioning experts set the record straight about a strength-training rule of thumb.
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For years, we've heard the strength-training rule of thumb that the more weight you lift, the longer you need to rest between sets. But is this really a hard-and-fast truth? And do longer rests between sets serve your particular health and fitness goals? (After all, some research finds *active recovery* beats out the passive kind.)

Here, what you need to know about rest intervals, based on the results *you're* looking for.

If want to tone, lose weight, or increase endurance...

Rest for: 20 to 60 seconds between sets

If your goal is to get in better shape by improving your muscle fitness or boosting your muscular endurance, keeping rest periods to a minimum is actually the better way to go, says Ryan Rogers, a certified strength and conditioning specialist at Fitness Quest 10 in San Diego, CA. (PS: Here's how often you should be doing heavy strength training workouts in the first place.) "For the majority of people who are looking to stay in shape and lose a little weight, I recommend minimizing rest by simply keeping moving during workouts."

To give muscles a little bit of a breather while keeping your heart rate up, Rogers typically has his clients complete circuit workouts in which the only rest is during the transition from one movement to the next—typically less than 30 seconds. "This approach helps burn more calories than resting fully between sets while still enabling the muscles to recover a bit so they can push a little more weight," he says. (Related: Why Some People Have an Easier Time Toning Their Muscles)

If you want to build strength...

Rest for: 2 to 5 minutes between sets

This enables muscles to replenish the energy they need for contraction and allow the nervous system to recover, says Pete McCall, C.S.C.S., an ACE-certified trainer based in San Diego, CA. "When lifting heavy weights such that you're performing 10 reps or less, proper rest and recovery is essential for the activation of muscle fibers, which ultimately leads to the hormone response that's responsible for muscle growth. Essentially, heavy lifting creates mechanical damage, and the hormones help repair the damaged tissue and initiate growth."

If you want bigger muscles…

Rest for: 1 minute between sets

If your main goal is hypertrophy—that is, an increase in the cross-sectional size of the muscles—this is the ideal rest period. "Pausing much longer than 60 seconds would compromise the metabolic stress aspect of training and decrease the potential for muscle growth, but resting for less than 60 seconds doesn't allow enough recuperation for the muscle to perform well in the next set," says Sabrena Jo, director of science and research content for ACE. (Related: What's the Difference Between Muscular Endurance and Muscular Strength?)

If you want to master form...

Rest for: 3 minutes between sets

Why three minutes? According to research published in the Journal of Strength and Conditioning Research, you'll recover more quickly than you would by resting only two minutes between sets. Plus, you'll have more time and energy to focus more completely on mastering the movement you're working on.

If you’re new to strength training…

Rest for: longer than you think you need to

Fairly new to strength training? "You'll benefit from more rest between sets so you don't push yourself to the point of nausea," says Rogers, "whereas someone who is in very good shape can rest less without much of a problem." (Also: Don't miss this strength training workout that's perfect for beginners.)

For beginners, taking more time to recover (without letting heart rate and body temperature fully return to resting levels) offers some additional benefits too, notes Fabio Comana, a lecturer at San Diego State University's School of Exercise and Nutritional Sciences. "For more inexperienced exercisers, longer recoveries can promote self-efficacy," he says. In other words, if an extra minute or two of rest between sets allows you to knock out that last effort, you'll have more confidence to stick with the workout long-term-which, of course, is the best way to see results, no matter what your goal. (Related: Common Weight Lifting Questions for Beginners Who Are Ready to Lift Heavy)