The muscle and bone systems are constantly changing and reacting throughout our lives; and the effects are different for men and women, but remarkably similar. Both muscle and bone will undergo a normal decline as we age; somewhere around the age of 25 in men. Muscles lose strength and power for various reasons:
1. muscles lose mass: there is a decrease in muscle fiber size and a decrease in muscle fiber quantity, starting at the age of 25, due to decreases in estrogen, testosterone, and Insulin-like Growth Factor-1 (IGF-1).
2. loss of motor units: the number of motor nerves that innervate muscle cells decreases
3. less muscle protein synthesis
4. loss of aerobic capacity: this is multifactorial in itself
5. loss of synchronization of the firing of motor units: also, multifactorial, such as with prior sciataca or disc herniation
Bones lose mass as we age because of several reasons:
1. loss of sensitivity of bones to muscle: loss of testosterone, IGF-1, and estrogen decreases bone response to mechanical stimulation by muscles and result in loss of muscle mass.
2. loss of muscle mass, area, and strength: due to loss of IGF-1, estrogen, and testosterone and this loss of muscle can also decrease the stimulation on bones.
3. increased bone resorption: due to loss of estrogen and testosterone
You can counteract this decline in bone and muscle health with strength and endurance training. Regular strenuous exercise (20-60min, 3-5 days/week)increases muscle strength and power, aerobic capacity, and bone density. Currently, no medications are approved for the treatment of muscle loss that occurs with aging and some treatments, including testosterone, can have dangerous side effects. For bone loss, exercise can increase the stimulation on bones by muscles and improve power and balance to decrease your risk of falls. Many medications exist for treating thin bones, including testosterone in men, but it appears that exercise can be as effective and both treatments should be implemented.
If you are concerned about your bone and muscle health, you should check with your doctor to see if an underlying medical condition is present, or if this a natural process with aging. Your doctor may prescribe medications and exercise to treat your issues.
Valley Sports & Spine Clinic
Giving you Back your Life
Dr Ethan Colliver