by: Dr. Gabe Mirkin, M.D.
As you age, expect your muscles to become smaller and weaker. Because of this, you lose strength and mobility. You walk slower, tire earlier, lose coordination and are at increased risk for falling, breaking bones, and injuring yourself. Lack of exercise is the main reason for the progressive weakness of aging (Exerc Sport Sci Rev, July, 2013;41(3):169-173). The most effective way to maintain muscle strength as you age is to exercise against resistance.
Causes of Progressive Weakness With Aging
Progressive strength loss with aging is caused by decreasing ability to make muscle from the protein that you eat (FASEB J, 2005;19:422-4), and to enlarge muscles from the exercise that you do (Skelet Muscle, 2011;1:11).
Taking extra protein does not help older non-athletes grow larger muscles. A group of healthy 70-year old men and women started on a 24-week program of lifting weights three times a week. Half were give protein supplements and half were given placebos. The extra protein had no beneficial effect on muscle size, strength, or anything else (Med Sci Sports & Ex, March, 2013;45(3):542-552).
However, in just 12 weeks, lifting weights caused both groups to grow larger and stronger muscles and markedly improved many factors that are linked to preventing diabetes and other chronic diseases. They had lower blood levels of triglycerides, sugar, insulin, and cholesterol, and lower blood pressure.
These were 70-year old non athletes. There is data to show that younger athletes who take intense workouts can grow larger muscles if they take protein and sugar immediately after they finish hard exercise. The sugar calls out insulin which increases the uptake into muscles of amino acids from dietary protein (Am J Clin Nutr, 2011;93:322-31).
What Does this Mean for You?
If you are older than 60, you will not prevent progressive loss of muscle, bone and strength by eating extra protein or taking protein supplements. It is possible that you are not meeting your requirements for protein, but that is incredibly unlikely in most North Americans who eat too much and therefore get far more protein than they need. You CAN help to prevent this loss of strength by lifting weights. You will also lower high blood sugar, insulin, triglycerides and blood pressure, all of which will reduce your chances for diabetes and heart attacks.