Muscle wasting (muscle atrophy) is the loss of muscle mass due to muscle weakness and shrinkage. Certain medical conditions and lifestyle habits cause muscle loss as you age. However, maintaining muscle mass means maintaining quality of life and independence. The body naturally begins to lose muscle mass around age 30.
In addition to certain medical conditions such as amyotrophic lateral sclerosis, factors such as inadequate protein intake and lack of physical activity play a major role in aggravating muscle loss.
Some common causes of muscle loss include:
1. Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis (ALS) is a progressive disease that affects nerve cells throughout the body. Under normal circumstances, nerve cells in the brain and spinal cord signal muscles to move. In people with ALS, the nerve cells that control voluntary movement die and stop sending signals that support movement. Over time, due to lack of use, the muscles atrophy.
2. Muscular dystrophy
Muscular dystrophy (MD) is a genetic condition that causes progressive muscle weakness and wasting. According to the National Institute of Neurological Disorders and Stroke, MD is a group of more than 30 conditions that cause muscle weakness and degeneration. As the condition progresses, it can lead to difficulty with movement, interfere with breathing and heart function, and become life-threatening. In other cases, the condition can progress rapidly, shortening life expectancy.
3. Multiple sclerosis
Multiple sclerosis (MS) is an autoimmune disease that affects myelin. This condition damages nerves, which in turn affects muscles. Damaged nerves lose their ability to initiate muscle movement, leading to muscle atrophy.
4. Long-term inactivity
Prolonged inactivity, such as lying in bed for hours, can lead to a loss of muscle mass. According to the Journal of Physiology and Medicine, muscle atrophy can develop within 10 days in otherwise healthy but sedentary older adults.
5. Malnutrition
People who are malnourished have inadequate nutrient intakes that can cause muscle loss, leading to muscle atrophy. Malnutrition can stem from a variety of causes, including anorexia, mental illness, and persistent nausea. According to the Journal of Oxidative Medicine and Cellular Longevity, vitamin D deficiency can lead to muscle loss in people.
6. Aging
Muscle loss is a natural result of aging. The Muscle, Ligaments And Tendons Journal notes that dramatic changes in leg muscle mass occur after age 50, with muscle loss of 1-2% being normal. Further research has highlighted that, between the ages of 20 and 80, the average person loses 35-40% of their leg muscle mass.
