I last discussed all the changes that happen in your body as you age, including bone loss, cardiovascular and flexibility changes among other systems.
I would now like to focus and expand on one of them: muscle loss.
Muscle loss, if left unchecked, can occur at a rate of nine per cent per decade, and since so much of your body’s function depends on muscle strength levels, it is vital to reduce muscle loss (called atrophy) in order to maintain our independence as we age.
The two main causes of muscle loss are nutrition and inactivity.
Some of the recent research indicates that the loss of appetite and hunger response as a result of age causes an approximate 25 per cent reduction in food intake between 40 and 70 years of age. This decrease in consumption can lead to reductions in protein intake and important micronutrients. Many vitamins and minerals (such as Vitamin D) play key roles in healthy muscular and neural functioning, as well as bone health. If you suspect that you fall into this category, you should consult your family physician.
Muscle contractions from exercise cause the release of muscle growth hormones. These growth factors activate specialized cells in muscle (called satellite cells), which cause protein synthesis and an increase in muscle density.
Aerobic exercise and resistance exercise play a major role in the prevention of muscle innervation problems, which lead to muscle atrophy, so by exercising you can maintain the muscle mass you have, or even build muscle, and you will stimulate bone mass as well.
In order to stimulate the body and keep our muscles firing, maintaining nerve-muscle connections and muscle mass, adults need to perform a minimum amount of physical exercise. Adults need at least two-three hours of moderate-intensity aerobic activity every week and muscle strengthening activities that work all major muscle groups on two or more days a week.
If you don’t have any health problems that would preclude more intense activity, you could alternatively do an hour to 90 minutes of vigorous aerobic activity every week, and muscle strengthening activities on two or more days a week for all major muscle groups.
Cardiovascular exercise gets you breathing harder and your heart beating faster, as long as you’re doing them at a moderate or vigorous intensity for at least 10 minutes at a time. This could include pushing a lawn mower, walking fast, dancing, or biking to the store.
Many people, especially those who are older, may not be used to going to the gym to lift weights, but you don’t necessarily have to hit the gym in order to strengthen your muscles.
More vigorous gardening, such as shoveling, will work as will walking in hilly areas and taking the stairs whenever possible. But don’t be put off by the thought of going to a gym or recreation centre.
Most of these facilities now have changed the equipment and the atmosphere to be user-friendly and conducive for participation for all ages and abilities.
To gain health benefits, weight lifting and muscle strengthening activities need to be done to the point where it’s challenging for you to do by the end of 8 to 12 repetitions of an activity. Try to do at least one set of muscle strengthening activities, but to gain even more benefits, do 2 or 3 sets during your strengthening day. Just keep in mind that muscle-strengthening activities don’t count toward your aerobic activity total.
Eating well and maintaining the use of our muscles reduces the rate of bone and muscle loss, improves our quality of life and reduces the cost to the health care system.
Kerry Senchyna is a provincially registered kinesiologist.