your body prefers not to use amino acids the building blocks of muscle as an energy source unless it has to because it’s simply not the most efficient way for your body to get the energy it needs. your body will typically use the more efficient means of attaining energy first. weight lifting and aerobic exercise can complement each other well but if you have concerns with not being able to gain muscle mass keep the aerobic exercise at a moderate amount. it might be best to refrain from doing overly excessive endurance aerobic events. try doing high intensity interval training. interval training involves coupling short bursts of high intensity exercise with less intense recovery periods. for example you could run on a treadmill for 1 minute at 8mph and then jog for 30 seconds at 6mph repeating for a total of 10 to 15 minutes. this is just an example to illustrate the point; you can do different intensity levels and different work to rest ratios. consider also doing circuit training which is a workout regimen involving resistance training with very little rest in between exercise sets. this form of exercise is high intensity and helps keep your heart rate elevated so that it can function as aerobic exercise while providing a foundation for muscular strength and endurance. lastly make sure that you are getting enough protein in your diet. the essential amino acids necessary for muscular growth and development can only be obtained through dietary intake. if you’re not getting enough protein you won’t be building muscle regardless of your activity.
does aerobic exercise interfere with muscle gains from weightlifting?