Perhaps you have spent the winter building muscle at the gym, and now that the weather has started to warm up you are interested in taking up jogging. You might have heard some rumors that engaging in cardio might cause you to lose muscle mass. The science behind this idea is a little tricky and complicated, but as long as you fuel your body with enough calories, going for a jog will not make you lose muscle mass. The loss of muscle typically happens when your calorie intake does not exceed how many you burn in a day. Weight loss happens when you burn more than you intake- but that weight loss often comes in the form of fat as well as muscle. If you are someone that doesn’t want to lose muscle definition while improving your cardiovascular health, you just need to ensure that you enough throughout the day.