Sarcopenia is one of the major things that causes age-related frailty, physical disability, lack of balance, falls, and poor quality of life. Yet most people have never heard of it. Strangely, though, almost everyone is familiar with osteoporosis and dreads the possibility that they will eventually get it, but sarcopenia is actually a greater threat for most people. It’s not an exaggeration, in fact, to say it is one of the most serious threats to your health as you age. In the case of osteoporosis you’re concerned with bone loss as you age; sarcopenia, on the other hand, is related to the loss of muscle and strength as you age. And this loss can be dramatic, and it doesn’t just happen in old age. Muscles, as you likely know, plays a large role in your well-being and health, but they also plays an important role in fending off such things as stress, inflammation, cancer, Parkinson’s disease, Alzheimer’s disease and others.
What is Sarcopenia?
Although most people hate to think about it, after about 40 almost everyone starts a long slide into poor health and frailty. For most it is slow enough that they hardly notice it at first, and of course, it varies considerably from person to person. It is most serious, however, in people who have become inactive, and rarely exercise. The reason for this is that they are beginning to lose muscle. It starts gradually and speeds up as you get older. For most, the loss is about 3 to 5-percent per decade after 30. If you think about it, this means that by the time you reach 70 you have lost about 20-percent. And that’s a lot of muscle. To make things worse, you have now replaced most of the muscle lost with fat so you weigh at least the same, or in many cases, considerably more. And your new body (with its reduced muscle) has to carry around this new weight. Furthermore, it’s known that muscle loss increases even more dramatically after 70. And this is not just speculation; it can easily be seen on magnetic resonance images.
What this leads to is poor balance, a slower gait (walking) speed, increased probability of falling and breaking bones, and a large loss of vitality. Surprisingly, though, to a large degree, it is preventable.
Let’s look a little closer at what is actually happening during this time.
Major Contributions to Sarcopenia
What are the main things that cause sarcopenia? I’ll list them in this section, and look at each in detail in separate sections.
• The major cause is inactivity, but it is not the only one. It does, however, have an effect on the other causes. In general, people become less and less active as they grow older. One of the reasons, of course, is that they are losing muscle and strength, and find it difficult to exercise.
• Your motor neurons decrease naturally with age. They are responsible for the movement of your muscles.
• Your hormone levels decrease. We all know that a large number of hormones are at work in our body. They play a critical role in relation to your muscles and we couldn’t do without them. Yet, as we age, they decrease.
• Your protein synthesis rate decreases. Protein plays an important role in our body, particularly in relation to muscle. But again, as we age, its production gradually decreases.
Decrease of Motor Neurons
Our muscular system operates as a result of electrical signals that are initiated in neurons in the brain, and are sent to the various muscles that make it up. From the brain, they travel along nerves in our spinal column. When they hit a muscle they cause a contraction.
A motor neuron unit consists of the motor neuron and the muscle fibers that are connected to it. Motor neurons eventually die and this leads to the death of the attached muscle fibers.
We actually have two types of muscle fibers associated with motor units. They are referred to as fast twitch (FT) and slow twitch (ST). Fast twitch fibers contract rapidly, and are used when we lift heavy objects or sprint. Slow twitch fibers contract more slowly, but don’t tire as easily as FT’s. When a fast twitch motor unit dies it is usually replaced by a slow pitch one, so as we age there is a transition from a large number of FT muscle fibers to mostly ST fibers. This is why we slow down as we age (and can no longer sprint or lift heavy objects).
Decreased Hormonal Levels
Aging also affects our hormones, and since our muscles depend on them, they also affects our muscles. What hormones are we talking about? The main ones are: the growth hormones (GH), testosterone (T), and insulin-like growth factor (IGF-1). All of them play important roles in relation to loss of muscle mass over time. GH, T, and IGF-1 are all needed for protein maintenance; IGF-1 is also important in relation to the rate of muscle protein synthesis. GH also assists in the breakdown of fat, and T accelerates muscle building and speeds up recovery time. It might seem therefore that a “shot of synthetic hormones” would rejuvenate your body, and this is, of course, why athletes use them. But studies have shown that it is not very effective when used in older adults in this way, and can cause serious problems in younger people.
Decreased Protein Synthesis
The protein in your body is under the influence of two processes: breakdown and synthesis. The cells of your body change continually as you age. Indeed, as strange as it might seem, except for certain cells (in your brain and heart) the cells you now have in your body are all different from the ones you had only eight or ten years ago. And this also applies to muscle protein cells. Old protein cells die and are cleared out of your body, and new ones are made. So new protein cells are being continually synthesized, and of course muscles are made up mostly of protein. But as you age your protein synthesis rate gradually decreases, and therefore your rate of muscle-building and repair also gradually decreases.
Other Things That Affect Muscle Mass
Other than inactivity there are a number of things that affect your muscle mass, and a few of them are listed below.
• Stress, increased inflammation and an associated increase in the hormone cortisol.
• Poor diet. It is critical to maintain your weight as you age. As we saw earlier, gaining weight is bad because it is usually mostly fat, but losing weight can also be a problem. It is important to eat the proper nutrients; omega-3 is particularly important, as is protein.
• Disease. In many cases we can do little about this but it definitely affects our muscle mass.
What is the best thing we can do to overcome and prevent sarcopenia? Since it is mainly caused by inactivity, exercise is obviously the most important thing. The best type of exercise, however, is resistance exercise or what we usually referred to as weight lifting. But in this case the muscles need to be pushed beyond their usual work load. This is needed to trigger the fast twitch muscles, which is important. In particular, they should be taken to over 80-percent of their limit. Furthermore, your routine should consist of cycles of high and low intensity, and it should be progressive (gradually increase in intensity).
Resistance training of this type has been shown to be very effective in overcoming sarcopenia. It will not completely reverse all the damage you have done over the years, but it is very helpful.
It cannot create new muscle cells, but it will increase the size of the ones that are there and therefore increase your overall muscle mass. And, indeed, the effects can be quite dramatic. They will be noticeable within a few weeks. Before starting such a program, however, you should consult your doctor.
The program is best done using dumbbells (which are relatively cheap) and the weight of your body. It’s important to warm up first; this usually takes about five minutes. To determine the best weight to start with, you should determine what is called your one rep max (1RM). It is the maximum weight you can lift smoothly for one rep for a given exercise. For example, if you are doing a one arm bicep curl and the maximum you can lift is 35 pounds, your 1RM is 35 pounds. With 80% of this (28 pounds) you should be able to do about 8 to 10 reps. After a couple of weeks at this weight, however, you should increase it. This is the “progressive” part. You should exercise all your major muscle groups (pecs, abdominals, biceps etc.) in this way. Pushups and step-ups using your body weight are also helpful. Do about 10 reps of each and 2 to 3 sets. And make sure you cool down.
Barry Parker, Ph. D., is a professor emeritus (physics, biophysics) at Idaho State University. He is the author of 25 books on science, health, writing and music. He has a strong interest in health and fitness, self-improvement and music. His most recent book is “Learn from Yesterday, Live for Today, Hope for Tomorrow.” He is also the author of “Feel great Feel alive.” His website is http://www.Barryparkerbooks.com
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