Rest 90 to 120 seconds between sets to build muscle and strength. This lets your heart rate return to baseline and your muscles fully recover so you can lift the most weight in your next set. Fat loss comes from nutrition, not rest periods.
How long to rest between sets depends on your goal. If your goal is to build muscle and get stronger, then the latest research we have shows us you want to get your heart rate back down to baseline and you want your muscles to fully recover before going into your next set so you can lift the most weight for the most reps. Well, the latest research shows us it takes at least 90 to 120 seconds for those 2 things to happen. So at minimum, that's how long you should be resting between sets. But what if your goal is to lose fat and build muscle? Well, it's actually the same because fat loss is done through your nutrition, not your workout.
