What is the typical impact of aging on muscle and metabolism?
There is certainly a link in the body between aging and metabolism. In general, the older you get, the slower the metabolism and the more calories you need to maintain your body weight. Weight gain, over the years, is a common phenomenon.
The impact of aging on metabolism
Numerous studies conducted to understand why weight gain occurs as we age have provided a clear answer that body composition is changing and that this change is essentially responsible for the decline in metabolism. After the age of 45, you lose an average of almost 10% of your muscle mass every ten years. This amounts to losing between a third and a half pound of muscle a year and gaining as much in body fat. Since muscle mass spends more calories than fat, there is a decrease in the total number of calories needed.
However, other studies, in increasing numbers, argue that body composition alone does not explain the weight gain associated with the aging process. The lowering of calories used by organs, such as the heart and liver, appears to be manifested as the body ages.
Physical activity plays a role in body composition and metabolism during the aging process. Research has shown that most people gradually reduce their level of physical activity as they get older, which means they need fewer calories to maintain their weight and use their muscles, contributing to the general decline in muscle mass and other changes in body composition.
Overall, these age-related changes mean that a 50-year-old woman needs about 300 to 500 fewer calories a day than she needs at age 20 for the same body weight. In other words, weight gain after a certain age does not mean that you eat more, but eat the same proportions when you need fewer calories.
Aging and exercise
Is there anything that can slow down this part of the aging process? Yes Fortunately! It appears that exercise helps a lot to counteract this effect. Several studies have shown that muscle training (i.e. weight training) can, on its own, speed up metabolism and offset the decline that occurs during aging. Other studies, even more recent, suggest that endurance training (i.e. aerobic exercise) can promote metabolism and counterbalance weight gain that occurs during aging.