As you age, you can expect to suffer from sarcopenia (loss of muscle size and strength). A study of 378 older adults showed that the smaller the muscles in their arms, legs and trunk, the smaller and weaker the upper and lower chambers of their heart (J Am Geriatr Soc, Dec 2019;67:2568-2573). Having a smaller and weaker heart muscle puts a person closer to heart failure and premature death. Low skeletal muscle size predicts death in people who have chronic heart failure (Cardiology, March 25, 2019). Heart failure means that the heart became too weak to pump adequate amounts of oxygen to the brain. Heart failure is listed as a cause of death in 15 percent of the death certificates in the U.S., but the actual percentage is much higher because most of the people listed as dying from “natural causes” actually died from heart failure.
How Common is Sarcopenia?
Between 25 and 50 percent of North Americans over the age of 65 suffer from sarcopenia that is significant enough to limit their daily activities (J Am Geriatr Soc, 2004;52:80–85). We know that a regular exercise program is the best way to slow down this loss of strength and coordination, but even if you exercise regularly, you will still lose muscle as you age (Aging Male, September-December 2005). After age 40, most people lose more than eight percent of their muscle size per decade and by age 70, the rate of muscle loss nearly doubles to 15 percent per decade, markedly increasing risk for disability and disease (Am J Epidemiol, 1998;147(8):755–763; Nutr Rev, May 2003;61(5 Pt 1):157-67). The people who lose the most skeletal muscle are most at risk for falls and broken bones, and are usually the ones who die earliest.
Muscles are made up of hundreds of thousands of individual fibers, just as a rope is made up of many strands. Each muscle fiber is innervated by a single motor nerve. With aging you lose motor nerves, and with each loss of a nerve, you also lose the corresponding muscle fiber that it innervates. Thus, for example, the vastus medialis muscle in the front of your thigh contains about 800,000 muscle fibers when you are 20, but by age 60, it probably has only about 250,000 fibers. However, after a muscle fiber loses its primary nerve, other nerves covering other fibers can move over to stimulate that fiber in addition to stimulating their own primary muscle fibers. A regular exercise program can help to slow the loss of muscle fibers and improve mobility (Physiol Rev, Jan 1, 2019;99(1):427-511). Lifelong competitive athletes over 50 who train four to five times per week did not lose as many of the nerves that innervate muscles and therefore retained more muscle size and strength with aging than their non-athlete peers (The Physician and Sportsmedicine, October 2011;39(3):172-8). Lifelong competitive runners over 60 had almost the same number of muscle fibers as 25-year-olds.
Inflammation Linked to Heart Failure and Sarcopenia
Inflammation means that you have an overactive immune system that attacks you with the same white blood cells and cytokine chemicals that are supposed to kill invading germs (Int J Mol Sci, 2010; 11(4): 1509–1526). Heart attacks, heart failure, and sarcopenia are all associated with inflammation. Older people who suffer from severe sarcopenia are far more likely to have high levels of the markers of inflammation, measured with blood tests such as CRP, SED rate and adiponectin (Aging Clinical and Experimental Research, August 2017;29(4):745-752). Other conditions associated with inflammation include:
• being diabetic (Med J Aust, 2016;205(7):329-333)
• having low vitamin D levels (Molecular Aspects of Medicine, Dec 2008;29(6):407-4140)
• not exercising
• having any chronic disease
• having excess body fat (J Gerontology A Biol Sci Med Sci, 2011;66:888-895; Curr Gerontol Geriatr Res, 2012;2012:216185)
Recommendations for Treatment
Since inflammation is a major component of heart failure, heart attacks and sarcopenia, prevention and treatment should include an anti-inflammatory diet (Clin Nutr, April 18, 2019) and exercise, which will both decrease inflammation by dampening down your immune system. Resistance exercise can increase muscle size and strength in older people. If you are not already doing strength-training exercise, first check with your doctor to make sure you do not have any condition that may be harmed by exercise. Then join a gym and ask for instructions on how to use the weight-training machines. Since lifting lighter weights is less likely to cause injuries, I recommend lifting lighter weights (about 50 percent of your maximum) with more repetitions. You gain almost the same muscle growth by lifting a lighter weight many times as you do by lifting a heavier weight fewer times (Science Daily, July 12, 2016). End the workout immediately if you feel severe pain or if you have pain that does not go away as soon as you stop lifting the weight. See Weight Lifting for Middle-Age and Beyond
Other anti-inflammatory lifestyle habits include:
• maintaining a healthful weight
• avoiding smoke and alcohol
• keeping blood levels of hydroxy vitamin D above 20 ng/ml