Sarcopenia: As We Age Muscle Loss Occurs Clinton IA
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Internal Medicine, Geriatric Medicine
Internal Medicine, Rheumatology
Medical School: Univ Of Ia Coll Of Med, Iowa City Ia 52242
Graduation Year: 1964
Sarcopenia: As We Age Muscle Loss Occurs
Health and Fitness
|Sarcopenia: As we Age Muscle Loss Occurs |
By Richard Train
Jan 6, 2008, 09:34
The human body was not designed to last a few 100 years. As early as the 20 s a process starts in the our bodies know as Sarcopenia. By the time we are 40 Sarcopenia has started to reshape the human body in a fashion that makes most of us uncomfortable with ourselves. By the time we reach approximately 60 the acceleration process of muscle loss and fat cell gain has becomes quite noticeable.
In physically inactive people there is a loss of about [-0.5%] of lean muscle mass every year between age 25 and 60, and a corresponding decline in muscle strength. From age 60 on, the rate of loss doubles, to about 1%. It doubles again at age 70; again at age 80, and then again at age 90.
How does this translate to the human body? We are losing muscle mass, and that muscle mass is being replaced by fat cells. Typically an individual wonders why they develop a pooch gut, or why their thighs or buttocks are becoming larger. We realize we are not gaining muscle mass in these areas, but losing muscle mass and fat cells are gaining in size. Most people can envision this process occurring in their body from the age of 30 on.
Inactive people normally have the most servere atrophy (loss of muscle mass), but active people also may experience atrophy of the muscle. The greatest loss is experienced with the fast twitch (FT) versus the slow twitch (ST) muscles. The FT muscles are used for high-intensity, anaerobic movements (weight lifting) while the ST are employed for activities such as running, dancing, biking, etc.
With aging and inactivity, the most atrophy is seen in the fast twitch (FT) fibers which are recruited during high-intensity, anaerobic movements. Although sarcopenia is mostly seen in physically inactive individuals, it is also evident in individuals who remain physically active throughout their lives. Present finding suggests that physical inactivity is not the only contributing factor to sarcopenia. Current research is finding that the development of sarcopenia is a multifactor process. Many factors, including physical inactivity, motor-unit remodeling, decreased hormone levels, and decreased protein synthesis, may all contribute to sarcopenia. Fortunately, sarcopenia is partly reversible with appropriate exercise interventions.
The purpose of this article is to focus on Sarcopenia and the importance of resistance training in preventing it and reversing its effect. The other important aspect is the decrease of hormones and the reduction of protein synthesis to build and maintain muscle mass. These are also an effect of the aging process that few people are aware of.
What causes Sarcopenia?
1. The aging process
2. Physical inactivity
3. Reduction of hormone production in the human body as we age
ii. Human growth hormone
4. Decrease of p...