Exercise now and reap the benefits when you get older? That’s what a new study suggests. Sarcopenia or loss of lean body mass during the later years of life directly contributes to balance problems and the reduction in functional strength so many older people experience as they age. It also increases the risk of falling. Not only does sarcopenia make it more difficult for older people to do the things they enjoy, but it also increases their risk of dying prematurely.
How are muscles affected by sarcopenia? Sarcopenia leads to a reduction in muscle size as well as a decrease in muscle quality as fat replaces some of the muscle fibers. The number of motor units that supply muscle fibers also contracts. So you lose muscle fibers and muscles become weaker and less functional. The muscle fibers most profoundly affected are fast-twitch muscle fibers activated with lifting and high-intensity exercise. Type 1 fibers, those involved in endurance exercise, are less impacted by the aging process.
Exercising During Middle-Age: Does It Protect Against Sarcopenia?
Researchers at Tokyo University recently looked at the impact of exercise on age-related sarcopenia. They collected data like gait speed, one-leg standing time and grip strength and measured skeletal muscle mass in 1,000 Japanese men and women over the age of 65. The results? Elderly men and women who had exercised regularly during middle age were far less likely to be sarcopenic relative to those who hadn’t engaged in regular physical exercise.
The Driving Forces Behind Sarcopenia
Here’s a scary statistic for you. One study showed 27% of women and 23% of men between the ages of 64 and 70 have difficulty walking and an even greater number are unable to carry around a load weighing 25 pounds. Of course, these were adults who didn’t exercise. Exercise during mid-life, especially strength-training, makes it less likely you’ll fall into this category.
Three main factors directly contribute to sarcopenia: lack of exercise, hormonal changes, and inadequate nutrition, especially dietary protein deficiency. Lack of exercise is an obvious one. You start to lose muscle mass after the age of 30, but a portion of this loss can be prevented with regular strength training. As they say, “use or lose it.” Research clearly shows middle-age and older adults who resistance train maintain a higher level of strength than sedentary adults.
What about Nutrition?
You’re probably familiar with the RDA for protein – 0.8 grams of protein per kilogram of body weight and more for physically active individuals. There’s some thought that older people could benefit from higher quantities of protein than this. According to research published Current Opinion in Clinical Nutrition and Metabolism Care, this amount may be enough for nutritional purposes but not enough to prevent sarcopenia. This research suggests that older people should consume between 25 and 30 grams of protein at every meal to maximally stimulate protein synthesis. In addition, between 1 and 1.2 grams of protein per kilogram of body weight may be more appropriate for preserving muscle mass.
One of the best sources of protein is fish – and there are lots of reasons to add it to your diet. A study published in the American Journal of Clinical Nutrition showed a dose of four grams of omega-3s stimulated protein synthesis in older adults. Omega-3s seem to activate anabolic pathways involved in protein synthesis.
Sarcopenia and Hormones
The age-related decline in anabolic hormones, growth hormone, testosterone, and IGF-1, are other factors that contribute to sarcopenia. In addition, there’s some evidence that inflammatory chemicals like interleukin-6 play a role, possibly by damaging muscle fibers. High-intensity exercise boosts testosterone and growth hormone. There’s also some evidence that creatine supplements help to preserve muscle mass in older people. Eating a clean diet of unprocessed foods rich in natural antioxidants also helps to reduce inflammation that seems to contribute to sarcopenia, at least to some degree. So enjoy more fruits and vegetables!
Vitamin D and Sarcopenia
Vitamin D deficiency becomes more common with age – and low vitamin D levels may contribute to loss of muscle mass. A study published in Clinical Endocrinology suggests that getting adequate amounts of vitamin D is important for preserving lean body mass and preventing sarcopenia. Other research has linked low vitamin D with greater risk for sarcopenia. That’s why it’s so important to check a vitamin D level. Remember, you begin to lose muscle mass at age 30, so it’s never too early to take steps to reduce the loss of lean body mass through exercise and nutrition.
The Bottom Line?
Loss of muscle strength and mass is a very real concern and one that can lead to physical limitations and a reduced lifespan. You’re one step ahead of the game if you’re strength training – but nutrition counts too. Make sure you’re getting enough protein, vitamin D and omega-3s. The good news? Resistance training during the middle years of your life may offer some protection against sarcopenia as you get older. Train hard now and be healthier now – and later.
References:
Eurekalert.org. “Regular Exercise in Middle Age Protects Against Muscle Weakness Later in Life”
Aging, Physical Activity, and Health. Roy Shepherd. Human Kinetics Publisher. (1997)
Am J Prev Med. 2003 Oct;25(3):226-31.
Curr Opin Clin Nutr Metab Care. 2009 January; 12(1): 86-90.
J Lab Clin Med. 2001 Apr;137(4):231-43.
Life Extension Magazine. “Preventing Sarcopenia”
Clin Endocrinol (Oxf). 2010 Nov;73(5):581-7.
J Clin Endocrinol Metab, October 2011, 96(10):3250 -3256.
Am J Clin Nutr. 2011 Feb;93(2):402-12. doi: 10.3945/ajcn.110.005611.
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