Sarcopenia or age-related muscle loss is a natural part of getting older. Because people are living longer these days, sarcopenia is an increasingly prominent issue, affecting the health, well-being, and quality of life of the older population. Lost muscle mass does not have to be permanent, though, and it can be rebuilt and maintained with the right care.
At around age 30, people being to lose about one-tenth to one-half percent of muscle mass every year. After 50, this increases to one to two percent yearly. Sarcopenia affects as much as 50 percent of people in their 80s and up to 33 percent of all individuals in long-term care.
To diagnosis sarcopenia, a doctor must note both low muscle mass and low muscle function. Medical professionals determine the latter by examining the ability to stand with the feet together, how long it takes to walk eight feet, and the time it takes to rise from a chair and return to a seated position five times. Muscle mass is harder to evaluate and requires MRI and CT scans. Researchers have also identified some biomarkers for early detection.
One of the most researched causes of sarcopenia is neuromuscular degeneration. Normal aging is associated with progressive and permanent neuron loss, which, among other things, causes the denervation of muscle fibers. Muscle atrophy plays a role, as does an increase in fatty and connective tissues in the muscle fibers.
Sarcopenia is also caused by a decline in hormones, including testosterone and growth hormones. This decline leads to changes in body composition, like lower lean body mass and bone density. Aging has also been associated with high cortisol levels and vitamin D, both of which contribute to bone and muscle weakness. These changes lead to increased injuries and decreased activity, compounding muscle loss.
Insulin sensitivity contributes to sarcopenia, affecting the legs more than the arms. Physical inactivity is one of the risk factors for developing both insulin resistance and sarcopenia. Additional research into the differences between how the upper and lower limbs use glucose is needed to fully understand sarcopenia. Aging, inflammation, and obesity all contribute to insulin resistance, and the interplay between these factors significantly affects sarcopenia and other age-related conditions.
Inflammation and Oxidative Stress
Inflammation and oxidative stress also contribute to sarcopenia. With aging comes a state of low-grade, chronic system inflammation that experts believe predisposes older people to muscle loss. Aging causes increased oxidative stress, which could cause age-related mitochondrial mutations while also preventing cells from effectively removing dysfunctional mitochondria. This can cause a decrease in type II muscle fibers, which are larger than type I fibers and have more power but less endurance.
Sarcopenia affects older people in multiple ways and can greatly impact their mobility and quality of life. Less muscle mass means an increased risk of falls and fractures. One report from 2015 showed that compared to those without the condition, people with sarcopenia have more than double the risk of a low-trauma fracture from a fall, including broken legs, hips, arms, and collarbones.
Lifestyle Increases Sarcopenia Risk
Treatment for sarcopenia focuses on behavioral changes. Aging often leads to a reduction in appetite that results from many factors, like a decreased sensitivity of taste and smell or worsening GI problems. A decline in food intake, especially protein, contributes to the development and severity of sarcopenia. Physical inactivity also promotes muscle loss. The right exercise regimen is an essential part of treatment.
Progressive resistance training is the most effective workout for treating sarcopenia. This involves exercising against increased resistance two to three times a week for a minimum of eight weeks. The number of repetitions and sets should increase gradually over time, depending on how the person is improving. Gait speed and the ability to rise from and sit down in a chair may be used to evaluate progress.
Muscle Power and Strength
To treat sarcopenia, focus on building both strength and power. Power, or how efficiently and fast the muscles move, is more beneficial for activities of daily living. It is especially important to work on muscle power in the lower limbs as they are most affected by sarcopenia and essential for maintaining mobility.