Decreased muscle mass, also known as muscle atrophy or sarcopenia, refers to the loss of skeletal muscle tissue. Muscle loss can happen for various reasons, including:
- Aging - Typically after age 30, we slowly begin to lose muscle mass. Around 3-5% of muscle is lost per decade. By age 80, around 30% of muscle mass may be lost.
- Lack of physical activity - If muscles are not used regularly with resistance training and other exercise, they will shrink and become weaker, leading to reduced mass. The classic phrase "use it or lose it" applies here.
- Poor nutrition - Consuming inadequate protein and calories can accelerate muscle loss, especially during weight loss diets. Getting enough high-quality protein is key.
- Illness or injury - Certain diseases, hormonal disorders, and injuries/immobilization that restrict movement can spur rapid decreases in muscle size.
- Increased weakness
- Impaired balance and gait
- Higher risk of falls and fractures
- Reduced ability to perform daily activities
- Lower resting metabolism and fat burning
- Weight gain - more fat, less muscle
- Higher inflammation and insulin resistance