Muscles Weaken with Aging Even If You Exercise

You can expect to lose strength and muscle mass as you age. This increases your risk for developing disabilities and lifestyle diseases.GeroScience, 2020;42:1547–1578), such as:

• heart attacks (Eur Geriatric Medicine, 2016;7(3):220–3)
• diabetes (Med J Aust, 2016;205(7):329–33)
• osteoporosis and fractures (Arch Endocrinol Metab, 2015;59(1):59–65; J Gerontol A Biol Sci Med Sci, 2018;73(9):1199–204)
• depression and memory loss (GeroScience, 2020;42:1547–1578)
• loss of physical independence (J Nutr Health Aging, 2020;24(3):339–45; 2019;23(2):128–37)

At around 25 years old, progressive loss of muscle begins. It is caused by the loss of muscle fibers, and in a lesser degree by a decrease in type 2 strength fast-twitch fibers.J of the Neur Sci, April 1, 1988;84(2-3):275-294).

Why you lose muscle with aging

Every muscle in your body is composed of thousands upon thousands of muscle fibers. A rope is made up a number of strands. Each muscle fiber is innervated only by one nerve. As we age, nerves become less important. When a nerve attaches to a muscle fibre, it is also lost. While a 20-year old may have 800,000 muscle fibres in the vastuslateralis muscle in his front leg, it would likely have just 250,000 fibers by the age of 60. For a 60-year-old to have the same strength as a 20-year-old, the average muscle fiber needs to be three times as strong as the 20-year-old’s muscle fibers. While you cannot stop the loss in muscle fibers due to aging, you can increase each muscle fiber and slow down its decline by using strength-training machines, or lifting weights.Experimental Gerontology, 13 August 2013.

How to Strengthen Muscles

For muscles to grow and strengthen, you must exercise them against resistance. This will cause the muscle fibers to be damaged. You will know that you have done this because you will feel a burning in the stressed muscle during the later lifts and on the next day, your muscles will feel sore. For as many days as your muscles heal, you can lift lighter weights and engage in other sports. This is when you feel the soreness disappear. Once your muscles feel energized again, lift weights a few at a time or lighten weights for a while. Three times per week, you can build strength by doing 10 to 15 strength training exercises or machines (for different muscle groups). You should stop immediately if there is any pain, tearing, burning or discomfort.

Inactivity accelerates the loss of strength

Two weeks of immobilization of muscles in young people can cause them to lose their strength at a rate of 40 to 50 years. Your muscles begin to weaken as soon as you stop moving. The larger your muscles are, the more you will lose. Stronger, younger people tend to lose strength more quickly than weaker, older people.J of Rehab Med, June, 26, 2015).

Even if your resistance exercise routine is already established, you should be aware that prolonged lifting weights can cause muscle loss and strength. People who lift weights but then stop lifting weights lose muscle mass much quicker than those who have never lifted weights. Two pounds can be lost if you are bedridden for a week.Nutr RevApril 2013;71(4), 195-208. Even if your muscles aren’t immobilized, it is possible to lose around 11 percent of your muscle mass in ten days with no exercise.Scand J Med Sci Sports, 2011 Apr;21(2):215-234).

Weightlifters can experience a 20% decrease in muscle size when they take a week off from lifting. However, this is not due to loss of muscle fibers. The primary reason is the loss of glycogen (sugar) and water stored in the muscles.Scand J Med Sci Sports, 1999 Aug;9(4):209-13; Eur J Clin Nutr, 1999 Feb;53(2):126-33.) A weightlifter can return to lifting as soon as the sugar and/or water levels are back at their original levels.PhysiolApril 2013;113(4), 975-85. A full recovery of muscle strength will take longer than six weeks for those who are completely immobilized after being injured or ill.J Rehabil Med, 2015 Jun;47(6):552-60).

My Recommendations

A progressive resistance program should be part of every person’s regular exercise routine. It can prevent disability and even death. If you’ve never lifted weights before you should check with your doctor to make sure you don’t have any health issues. Also, in the beginning, get instructions for progressive resistance training.

Republished from DrMirkin.com

Gabe Mirkin is a long-time radio host and sports medicine doctor. This newsletter brings you the latest and most important tips for a healthy lifestyle. Dr. Mirkin has been a practicing physician for over 50 years and a radio host for 25 years. He is a graduate of Baylor University College of Medicine and Harvard University. He is one of only four doctors to be board certified in four specialty areas: Sports Medicine and Allergy, Immunology, Pediatrics, and Pediatric Immunology.

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