How long should you rest between sets to build muscle?

Rest at least a minute between sets, about 2–3 minutes on big compound lifts and 1½–2 on single-joint ones. Less than a minute costs you reps, and the lost reps cost you growth. Much more than 3 minutes adds time to your session but no muscle anyone has been able to measure. Within that range, rest longer when the lift is heavy, when you train close to failure and as the sets add up.

Why the rest matters: it saves reps

For decades, short rests (30–90 s) were the hypertrophy advice, on the idea that the hormone spike they cause builds muscle (IUSCA position stand, 2021). That idea didn’t hold up. Rest helps because it lets you do more reps in the next set.

The clearest test trained 28 people’s legs on the leg extension for 10 weeks, each leg on one of four plans. A leg that rested 3 minutes grew about twice as much as one that rested 1 minute (13 % against 7 %). But a 1-minute leg that added sets to match the 3-minute leg’s total work grew just as much, and a 3-minute leg held to the 1-minute leg’s work grew just as little (Longo et al. 2022).

How much rest is enough

The best meta-analysis so far pooled 9 trials. Resting more than 60 seconds gave a small edge in muscle growth, and it found no clear gain beyond about 90 seconds (Singer et al. 2024). In trained men, 3 minutes beat 1 minute over 8 weeks, in thigh growth and in strength (Schoenfeld et al. 2016). And in trained men who did 3 months with 2-minute rests and 3 months with 5-minute rests, the thighs grew the same (Ahtiainen et al. 2005).

Single-session studies show how many reps you lose. On the bench press, with 1 minute, reps fall from the second set. With 2 minutes, the first two sets hold. With 3, three sets hold (Ratamess et al. 2007). In squats and leg extensions with a 10-rep-max load, 2 and 3 minutes gave almost the same reps, and 1 minute gave a few fewer (Rosa et al. 2023).

Past that point, more rest buys little. Lifters who rested as long as they liked did more reps than those on a fixed 75 seconds, but gained the same upper-body strength over 8 weeks, and the fixed rest was 37 % more time-efficient (Simão et al. 2022).

What changes the right rest

• Big lifts need more rest. Squats, presses and rows tire more muscle and the whole body, so rest at least 2 minutes. Curls, raises and extensions recover faster, in 60–90 seconds (IUSCA position stand, 2021).
• Heavy sets need more. With a 3-rep max, the bench press needed 3–5 minutes to keep its reps, while a machine fly needed only 2 (Senna et al. 2016).
• Sets to failure need more. They drain far more of the muscle’s quick energy than the same reps spread over shorter sets (Gorostiaga et al. 2012).
• Later sets need a little more, because fatigue builds.
• Women recover faster between sets than men at the same effort, and did as many reps with 1 minute as men did with 3 (Ratamess et al. 2012).

Waiting for your heart rate to drop doesn’t help much. It tells you how your heart and lungs are doing, and little about whether the muscle has recovered.

How Workout Wizard does it

After you log a set, the app starts a rest timer it calls Smart Rests. It starts from the kind of lift: 3 minutes for leg compound lifts, 2½ for upper-body compound lifts, 2 for isolation lifts of a large muscle, 1½ for a small one. Then it adjusts for the load, the week’s target reps in reserve, which set you just did, a set that lost many reps, and your sex if you gave it. The result stays within the rests the studies tested for that kind of lift (2–5 minutes for compound lifts, 1½–3 for a large muscle’s isolation, 1¼–2 for a small one’s), in steps of 15 seconds, so your rest for a given exercise stays the same from week to week. The timer says why it chose that rest, for example “Upper-body compound lift · 1 RIR”.

You can add or take 15 seconds, skip it, or set your own rest for any exercise. It counts down on the Lock Screen and on your Apple Watch, which taps your wrist when it’s time.

Some of the adjustments are the app’s own estimates where studies give the direction but not the size, and the app says so in its science notes.

How long to rest, in short

Rest 2–3 minutes on compound lifts and 1½–2 on isolation lifts. Never go under a minute, and rarely over 5. Rest longer for heavy sets, sets near failure and later sets.

References

• Ahtiainen JP et al. 2005. Short vs. long rest period between the sets in hypertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men. J Strength Cond Res 19(3):572–582. doi:10.1519/15604.1.
• Gorostiaga EM et al. 2012. Energy metabolism during repeated sets of leg press exercise leading to failure or not. PLoS One 7(7):e40621. doi:10.1371/journal.pone.0040621.
• Longo AR et al. 2022. Volume load rather than resting interval influences muscle hypertrophy during high-intensity resistance training. J Strength Cond Res 36(6):1554–1559. doi:10.1519/JSC.0000000000003668.
• Ratamess NA et al. 2007. The effect of rest interval length on metabolic responses to the bench press exercise. Eur J Appl Physiol 100(1):1–17. doi:10.1007/s00421-007-0394-y.
• Ratamess NA et al. 2012. The effects of rest interval length on acute bench press performance: the influence of gender and muscle strength. J Strength Cond Res 26(7):1817–1826. doi:10.1519/JSC.0b013e31825bb492.
• Rosa A et al. 2023. Repetition performance, rating of perceived discomfort, and blood lactate responses to different rest interval lengths in single-joint and multijoint lower-body exercise. J Strength Cond Res 37(7):1350–1357. doi:10.1519/JSC.0000000000004508.
• Schoenfeld BJ et al. 2016. Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. J Strength Cond Res 30(7):1805–1812. doi:10.1519/JSC.0000000000001272.
• Schoenfeld BJ, Fisher JP, Grgic J et al. 2021. Resistance training recommendations to maximize muscle hypertrophy in an athletic population: position stand of the IUSCA. Int J Strength Cond 1(1). doi:10.47206/ijsc.v1i1.81.
• Senna GW et al. 2016. Effect of different interset rest intervals on performance of single and multijoint exercises with near-maximal loads. J Strength Cond Res 30(3):710–716. doi:10.1519/JSC.0000000000001142.
• Simão R et al. 2022. Acute and long-term comparison of fixed vs. self-selected rest interval between sets on upper-body strength. J Strength Cond Res 36(2):540–544. doi:10.1519/JSC.0000000000003606.
• Singer A et al. 2024. Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy. Front Sports Act Living 6:1429789. doi:10.3389/fspor.2024.1429789.