Skeletal muscle accounts for about 40% of adult body weight. In addition to their primary functions (posture, movement, and breathing), skeletal muscles also store important nutrients and regulate metabolism.
As people age, they lose about 30% of their maximum muscle mass by the age of 80, a process exacerbated by the lack of exercise and malnutrition. We call this process sarcopenia. It results in lower basal metabolic rate, weakness, reduced activity levels, decreased bone density, and low calorie needs, and causes an increase in body fat related to hypertension and abnormal glucose tolerance.
The MRI images below show the composition of muscle tissue of a 24 y.o. (c), a sedentary 66 y.o. (d), and an active 66 y.o. (e).
As people age, they lose about 30% of their maximum muscle mass by the age of 80, a process exacerbated by the lack of exercise and malnutrition. We call this process sarcopenia. It results in lower basal metabolic rate, weakness, reduced activity levels, decreased bone density, and low calorie needs, and causes an increase in body fat related to hypertension and abnormal glucose tolerance.
The MRI images below show the composition of muscle tissue of a 24 y.o. (c), a sedentary 66 y.o. (d), and an active 66 y.o. (e).
A sedentary 66 y.o. takes 3,141 steps per day for a total of 22 minutes of physical activity, while an active 66 y.o. completes 12,445 steps per day making them active for 130 minutes a day.
Correlation between the level of physical activity and the size of skeletal muscles
As muscle mass decreases with age, more fat penetrates into muscle tissues, but physical activity enables one to retain more skeletal muscle in the process of aging.
The good news is that many consequences of sarcopenia are preventable or even reversible. Progressive resistance exercises can produce substantial increases in strength and muscle size, even among the elderly. Such exercises focus on large muscle groups throughout your whole body and involve participants exercising their muscles against some type of resistance that is progressively increased as their strength improves. Common examples include push-ups, wall sits, and walking on a treadmill.
Regular resistance exercise induces muscle hypertrophy due to a chronically elevated level of protein. Although older people with sarcopenia show age-related resistance to anabolism in response to exercise and protein intake, the cumulative effect of regular exercise and adequate protein intake still helps repair and maintain muscle.
The good news is that many consequences of sarcopenia are preventable or even reversible. Progressive resistance exercises can produce substantial increases in strength and muscle size, even among the elderly. Such exercises focus on large muscle groups throughout your whole body and involve participants exercising their muscles against some type of resistance that is progressively increased as their strength improves. Common examples include push-ups, wall sits, and walking on a treadmill.
Regular resistance exercise induces muscle hypertrophy due to a chronically elevated level of protein. Although older people with sarcopenia show age-related resistance to anabolism in response to exercise and protein intake, the cumulative effect of regular exercise and adequate protein intake still helps repair and maintain muscle.
An example of progressive resistance training program for older people
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