Pay Attention to Your Rest Periods
Updated: May 28, 2020
Rest periods between sets would be one of the most neglected aspects of training and program design. The whole training affect can be changed depending on how long you rest, so I think it is an important part of training that you should pay more attention to. The length of the rest period affects the recovery between sets and the hormonal responses to a training session.
The basic principle is, lower the reps and the higher the load, the longer the rest. Higher reps and lighter load, you need less rest.
In general, when training for maximal strength (1-5 reps at 85% or more) longer rest periods are warranted to allow time for the central nervous system to recover. Typically, larger muscle mass is being used in strength phases and the exercises tend to require more coordination such as when performing cleans or snatches. Two to four minutes is the general recommendation but there are many factors that can influence this as well. The strength of the athlete being one. For example, I have heard of world class powerlifters and strongman competitors resting a minimum of 8 minutes between sets, and some recommend even more. For most of us 2-4 minutes will be fine. This should allow enough time to prevent fatigue and allow you to perform repeated efforts at a high intensity. You should get stronger each set (up to a point) when training for maximal strength. If you aren’t experiencing this in your sessions, maybe your rest period is too short. On the other hand, if you are waiting too long, you may not see the benefits either as the post-tetanic facilitation effect might be lost, basically your nervous system may calm down too much before performing the next set.
For hypertrophy and body composition, the rest periods are shorter. You are looking to create more metabolic demands with this type of training, compared to strength training where a large emphasis is on the nervous system. Shorter rest periods, when using multi-joint movements, will also create more lactic acid, which has been said to increase growth hormone. This will lead to more fat loss over time. Kraemer and his colleagues determined that the highest growth hormone, beta-endorphin, and cortisol concentrations were observed when 10RM multiple sets (3 sets) of exercises were performed separated by a short (1-minute) rest. Testosterone was responsive to both higher intensities (5RM with 3 min rest) and also lower intensities with a shorter rest (10RM with 1 min rest).
There are many factors at play but the takeaway is to pay attention to your rest periods and match them to your goal.
When training for pure speed or power, then full recovery should be allowed between sets. This type of training is about quality, not quantity. Often, these sessions turn into speed endurance type workouts simply because there isn't enough rest given between sets.
Another problem area I see is with hypertrophy and body comp training. If you rest too long, results will be minimized. As the workout starts to get hard, people want to extend their rest periods more and more. It is important to stick to them to get the training response you are after. Resting too long in this case will change the adaptations that will take place.
Strength training isn’t impacted as much because you have more leeway and most people rest too long as it is.