Your strength, as you age, is a predictor of your mortality!

It has been known for sometime that strength is related to health and longevity. However, recent research has shown some direct correlations between muscle strength and mortality. In particular, there were 3 articles of significance reporting these findings in different ways. Reported in the Journal of Gerontology (2006, Vol. 61A, No. 1, 72–77) it was realized that the loss of muscle mass (sarcopenia) was not as important as muscle strength. Until this study, the loss of muscle mass did not explain the relationship between the amount of muscle and mortality. Both men and women were studied to determine the importance of strength as the key marker in old age for mortality assessment.

In studying over 2200 men and women associations were discovered, relative to muscle strength, that were previously not recognized. The levels of hormones, testosterone and growth hormone, even at the ages of the studied subjects (between 70-79 years old) are very important in determining strength.

Why strength is such an important criteria to measure? Strength is reduced with increased disease, illness and deconditioning. Pain, such as with various forms of arthritis, also interferes with strength, as pain prevents or reduces activity; subsequently, this results in muscle atrophy (loss) from disuse.

In the same journal (p.92–96) a second group of researchers from Finland, reported on strength in women. They found a direct correlation between strength in women, at 75 years old and above, the amount of Estradiol (female hormone) present and the number of falls they had. Estradiol is the most bioactive of the female hormones. It is not entirely clear why estrogens have this affect however, it is known that estrogens do affect the central nervous system (brain) and neurons (nerve cells), which affect muscle behavior, coordination and reaction time. Low estrogens seem to adversely affect not only muscle strength but the way muscles work in coordination and with spatial movements.

The British Medical Journal reported this year (BMJ 2008; 337; 439), on a 19-year study, involving more than 8700 men between the ages of 20-80 years and the relationship between strength and mortality. The study confirmed previous research that declines in strength coincide with all-cause mortality. All-cause means death from any reason. The size and scope of this research is significant giving the results statistical confirmation and significance. In particular, the researchers found that, in men, there’s a direct association between muscle strength and protective cardiopulmonary fitness. The same association is being studied in women.

What does this mean to you? It means that there’s great importance in the need for weight bearing and aerobic exercises. It also means you shouldn’t wait until you’re in your 60’s and 70’s to get started. You must start before there’s a decline in muscle strength. Without exercise, of any form, you’ll also loose mitochondria, the energy factories of your cells, and their efficiency in producing ATP, the form of energy the body requires.

Of course, exercise is something that can be done on your own but is best done, initially, with someone (a personal trainer) who can give you advice about what exercises do what. You don’t necessarily need to invest long term in a personal trainer but you do need to know what exercises are the best and how to do them to prevent injury. Its’ important you consult your health care provider to see if you can exercise and to monitor your hormones. The hormones of greatest importance are: estrogens (E) and progesterone (P) for women, and testosterone (T), sex hormone binding globulin (SHBG) and growth hormone (hGH) for both sexes. The levels needed to be maintained for the effectiveness of these hormones are optimal ranges not their normal ranges. Optimal range is 70% of the upper normal limit. Human Growth Hormone requires a health care professional who can assess all the parameters for the use of this medication. Elevated levels of SHBG, affects the performance of E.

The value of studies such as the ones mentioned here are best used for prevention not treatment.

By Richard W. Walker, Jr. MD