Live Lean for Health We begin to lose lean muscle after the age of 30 through a process called Sarcopenia. Common minor side-effects are premature aging, pronounced wrinkling, sunken cheeks, loss of strength to do simple things. Our metabolism decreases as we lose muscle and our body fat% increases. Later it can result in metabolic disorders like type 2 diabetes., since muscle tissue helps regulate blood sugar, insulin and other things. Muscle Building Tips: Effective resistance training at least twice a week, combined with a protein and nutrient rich diet, specific for your body composition, will increase muscle mass. Cardio improves our response to insulin, helping with muscle repair. Helps with blood flow to get nutrients to muscle. How to do Both In addition to cardio classes I like high intensity, cardiovascular strength training workouts… so we get the benefits of both.