Rest is an important part of any workout routine. For instance, when you strength train, you break your muscles down. Rest allows your muscles to repair themselves. And that’s how you get stronger. You don’t have to spend your rest day lying on the couch. A rest day is more of a non-training day than an activity-free day. So you can move around and maybe even include some light exercise. A good rule of thumb is to try to have a rest day every 3 to 5 days.