By Maryann Tomovich Jacobsen, MS, RD
Since I turned 40, I think a lot about the state of my muscle. That’s because as people age they gradually lose some of the lean stuff. The technical term is “sarcopenia” (pronounced Sarko-peen-Ya), the age-associated loss of muscle, strength, and function.
Starting at age 30, for example, inactive people lose about 3-5% muscle each decade, which accelerates around age 75. Sarcopenia is a key factor in a lowered metabolism, increased fat tissue, and the occurrence of fractures and frailty in older adults. According to a 2004 study in Journal of the American Geriatric Society, the U.S. healthcare cost attributable to sarcopenia in 2000 was about 18.5 billion.
Why we lose muscle
As we age, the body gradually loses more agile “fast twitch” muscle fibers and the less effective “slow twitch” fibers take over. The body also has a lower rate of protein synthesis or “building protein” in the body. Hormonal changes such as lower levels of growth hormone, testosterone, and insulin-like growth hormone also negatively affect muscle maintenance
Decreased activity and inadequate calories and protein contribute to sarcopenia as well. Even though active people lose muscle at a slower rate, they are not exempt.
What can be done?
Research shows that resistance training can do wonders at preventing and treating sarcopenia. The process of continually overloading muscle helps increase the body’s ability to build proteins and maintain more fast twitch muscle fibers and has a positive effect on hormone concentrations. Studies show that people of all ages can see results from resistance training as early as two weeks!
The American College of Sports Medicine (ACSM) recommends weight training 2-3 times per week, working all major muscle groups, with 48-72 hours off to give muscles a rest. For those with little experience resistance training, a certified personal trainer can help get you started.
The role of diet
There are two key factors that play a role with diet and they are calories and protein. Too few calories means protein will be used for energy needs and not building muscle. With enough calories, protein becomes vital — both in terms of quality, quantity, and timing.
ACSM recommends active people get about 1.2-1.7g/kg per body weight. For a 140-pound woman that is about 95g per day and 125g for a 200-pound man (at 1.5g/kg). An ounce of animal protein has about 7g per serving so a 4-ounce portion of chicken gives you just under 30g. Other sources include dairy (8g per 8ounce cup of milk) and beans (6-8g per 1/2 cup) — see this article for more specifics on protein.
The key is to evenly distribute protein throughout the day. According to a 2009 study in the Academy of Nutrition and Dietetics, a 30g-protein meal increased muscle protein synthesis as much as a 90g meal did, in the young and elderly. So adding copious amounts of protein to one eating occasion is not necessary or effective.
Timing around workouts is key, as eating carbohydrates with some protein after workouts helps replace loss of stored carbohydrates (glycogen) and aids in muscle repair and recovery. Examples of foods with this composition include yogurt, energy/protein bars, string cheese with whole grain crackers, trail mix (dried fruit, nuts, pretzels), and ½ a peanut butter sandwich.
No one can stop the aging process, but finding ways to stay strong can increase quality of life now, and the years to come.
Do you think much about the state of your muscle? Is it an important part of your healthy lifestyle?