Factors Determining How Long To Rest Between Sets In A Workout

If you’re wondering how long you should rest between sets, don’t listen to people who give you standard set times; it’s more complicated than that. How long you rest for between sets is determined by many factors, including how heavy you’re lifting and what muscles you’re working/exercises you’re doing. And even after that, there’s another question which rarely gets asked about rest periods – should they be varied like everything else?

Factor 1: How heavy are you lifting?

If you’re training for strength you’re lifting heavy as possible with low reps, and lifting heavy taxes the CNS quickly – the CNS fails before the muscle fibers are fatigued. The CNS also recuperates more slowly than the muscles (around 5x slower), so if you do your next set too soon you will fall well short of optimal CNS training. For heavy sets (which will be low rep) you may need to rest for approximately 20x longer than the actual set took to complete. So if a set took 15 seconds to complete, 15 seconds x 20 = 300 seconds or 5 minutes.

If you’re training for muscle size then your task is to break down as much muscle protein as possible, and you will be doing so by using moderate weights for higher reps, allowing you to break down far more muscle protein (exhausting the muscles) before the CNS fails. If you take too long in between sets, your muscles will recover too much and you will end up working the same muscle fibers again and won’t reach new fibers. You need to give your CNS adequate time to recuperate or you will fail prematurely and won’t hit the type 2a and type 2b fast twitch muscle fibers (which give the most size) – let alone recruit any extra muscle fibers. For moderate weight (moderate to you) you will be able to use substantially shorter rest than you would when training with the heaviest weights you can handle. How short your rest should be also depends on whether you intend on using the same weight again or going lower, obviously the lower the weight you use for your next set the shorter the rest break you can get away with.  It’s also important to mention that if you have a very short break and use lesser weights and continue into the territory of the pump and possibly lactic acid, you’re training the energy system, so will experience sarcoplasm growth, not just myofibril – though both contribute to muscle size.

Factor 2: Which muscles are you training?

If you’re training large muscles you need more time to recover in between sets, if you’re training small muscles they need less time to recover. All things being equal, an individual with larger muscles will tend to need more rest to recover than someone with smaller muscles.

Which exercises you use will also play a role in determining how long you need to rest in between sets. If you’re using compound exercises, you’re involving multiple muscle groups into a lift. Obviously it’ll take the CNS and muscles longer to recovery from the bench press (actively involving the pectorals, triceps and deltoids to name just a few muscles) than it would to recuperate from triceps extensions alone.

Should there be variation?

This question has already been answered partially – to achieve maximum size, strength and fitness, you need sarcoplasm as well as myofibril growth and different rest periods will enable you to train for both.

Furthermore, rest periods really are like anything else, if you continue to give your body what it has become accustomed to things will become stale. Vary your rest periods not just to help you better target different areas of muscle growth but because complacency has no place in any form of training if you want to constantly improve.