Training to build muscle mass can be really hard work!
And depending on your goals, you may find your training needs to be quite intense.
So the question is, how much rest is recommended?
Let’s talk about rest intervals. The general rule is to rest for about 60 seconds between sets, with 90–120 seconds of rest taken between sets when training large muscle groups.
Your training goals will also determine the length of your rest intervals. If you are training for fitness, allow 60-90 seconds of rest between sets, 2-4 minutes when training for strength gains and 20-30 seconds if your goal is to reduce body fat.
Be careful not to over train, or train too long. Weight training stimulates the natural release of growth hormone and testosterone, which are important for muscle development and fat loss. However, the spike in these beneficial hormonal levels achieved through exercise can rapidly decline if a workout is too long and levels of the stress hormone cortisol will increase sharply.
When this happens cortisol can actually break down muscle, so aim to keep your weight training workout to 30-60 minutes, depending on the intensity. If you combine cardio and weight training avoid exceeding 60-75 minutes.