Life Extension Magazine August 2003
Protecting Muscle Mass As You Age
Testosterone's role in muscle mass
Testosterone, the hormone that brings about the changes that literally turns a boy into a man, has been in the press lately in regards to its effects on age-related impotence. While adequate levels of testosterone are certainly vital to the sexual well being of both men and women, studies are now showing that testosterone supplementation may play a very important role in the fight against age-induced muscle loss.
It has been well documented that testosterone levels decrease in men as they age.19 It's also been shown that in hypogonadal men (men who have low testosterone levels due to disease or other non-age related factors), testosterone supplementation increases fat-free body mass, as well as increasing muscle size and strength.20 With these two facts in mind, researchers have begun to examine the effects of testosterone supplementation on muscle mass in the elderly, and initial reports have been quite positive. One of the first studies done, in 1995, showed that testosterone, given to six men (age 64 to 69) who had low testosterone levels, caused a measurable increase in skeletal muscle protein synthesis and strength.21 A more recent study, published last year, examined the effects of testosterone supplementation on 10 men, 60 to 78 years in age, in a double-blind trial.22 The results showed that testosterone supplementation increased fat-free mass, improved exercise endurance time and improved balance.
Human growth hormone-is it the fountain of youth?
An entry of "human growth hormone" into any common Internet search engine will yield thousands of hits. This hormone, present in high amounts in our younger years and falling precipitously as we age, has been touted by many as the proverbial fountain of youth. While human growth hormone (HGH) may or may not provide a way in which humans can significantly increase their life span, it does show great promise in preventing or even reversing the harmful effects of sarcopenia in both elderly women and men.
A landmark study published in the New England Journal of Medicine reported on the effects of giving HGH to 21 otherwise healthy men, aged 61 to 81, over a six-month period.23 The men who received the HGH showed an 8.8% increase in lean body mass, a 14.4% increase in adipose tissue mass and a 1.6% increase in average lumbar spine vertebral bone density. The authors of the study concluded that "the findings in this study are consistent with the hypothesis that the decrease in lean body mass [skeletal muscle], the increase in adipose-tissue mass and the thinning of the skin that occur in older men are caused in part by reduced activity of the [human] growth hormone-IGF-1 axis, and can be restored in part by the administration of human growth hormone." The news for women is also encouraging: studies have indicated that HGH supplementation in women can restore youthful levels and help increase skeletal muscle mass lost to sarcopenia. A study done on 16 women, 70 to 73 years of age, showed that four weeks of HGH supplementation increased their HGH blood levels and lean body mass while causing a significant decrease in overall body fat.24
While HGH might sound like the fountain of youth to some, there can be potentially significant drawbacks. Although mainstream medicine can no longer ignore the potential anti-aging benefits of HGH supplementation, anti-aging proponents would be unwise to turn a blind eye to some reported significant side effects, including water retention, headaches, lethargy and joint swelling. Whereas these side effects may be lessened with lower doses of HGH, supplementing with this powerful hormone should only be considered under care of a physician well versed in anti-aging medicine. Also, HGH replacement therapy doesn't come cheap, with injections costing as much as thousands of dollars monthly.
Amino acid supplements may restore youthful HGH levels
Fortunately, for those that want to wait for more definitive HGH studies or can't afford the cost of such therapy, there may be a much more economical and safe way to boost HGH levels. There is now a considerable body of literature indicating that certain amino acids, when taken in high enough doses, can stimulate a significant increase in HGH levels. An early study done in 1981 showed that 1200 mg of l-arginine and 1200 mg of l-lysine, when taken together, produced a measurable increase in HGH secretion. Interestingly, neither of these amino acids showed an effect on HGH levels when taken separately, even at the same doses. A more recent study, done in 1997, again showed that relatively low doses of arginine and lysine (1500 mg of each), when taken together increase HGH levels.26 While most studies have been done in people less than 30 years of age, a study done at the Louisiana State University College of Medicine has shown that even the elderly can benefit from amino acid supplements. Nine men, aged 32 to 64, were given 2000 mg of the amino acid glutamine; 90 minutes after ingestion, HGH levels increased over 400% from baseline.27
Don't let sarcopenia rob you of mobility and life
Many of us can remember our grandmothers as frail, hunchbacked little old ladies whose bones were as brittle as those of a new-born baby bird, and whose muscles could barely lift her out of her favorite rocking chair. Fortunately, we live in an age where researchers in the anti-aging field are finding ways in which we can prevent and treat sarcopenia, osteoporosis and other disabling aspects of aging. Through resistance training, natural supplements and possibly hormonal replacement therapy, your muscles may be able to stay young and healthy well into your 60s, 70s and 80s. Perhaps not so distant in the future our model of a grandmother, rather than being that of a debilitated, empathic figure, will soon be thought of as a vibrant woman with strong arms and spry legs playing tennis with her grandchildren.
1. Bross R, Javanbakht M, Bhasin S. Anabolic interventions for aging-associated sarcopenia. Jour Clin Endo Metab 1999; 84(1): 3420-30.
2. Janssen I et al. Low relative skeletal muscle mass (sarcopenia) in older persons is associated with functional impairment and physical disability. J Am Geriatr Soc 2002 May;50(5):889-96.
3. Iannuzzi-Sucich M, Prestwood KM, Kenny AM. Prevalence of sarcopenia and predictors of skeletal muscle mass in healthy, older men and women. Jour Ger A Biol Sci Med Sci 2002; 57(12): 772-7.
4. Baumgartner RN et al. Epidemiology of sarcopenia among the elderly in New Mexico. Am J Epi 1998; 147: 755-63.
5. Baungartner RN et al. Predictors of skeletal muscle mass in elderly men and women. Mech aging development 1999; 107(2): 123-36.
6. O'Rourke KS. Myopathies in the elderly. Rheu Dis Clin North Am 2000; 26(3): 647-72.
8. Aniansson A, Gustafsson E. Physical training in elderly men. Clin Physio 1981; 1: 87-98.
9. Frontera WR et al. Strength conditioning in older men: skeletal muscle hypertrophy and improved function. J Appl Physio 1992; 64: 1038-44.
10. Pyka et al. Muscle strength and fiber adaptations to a year-long resistance training program in elderly men and women. J Gero 1994; 49: 22-27.
11. Sacheck JM et al. Vitamin E reduces muscle damage and biomarkers of oxidative stress after exercise. FASEB Jour 2002; 16: 1137.
12. Gotshalk LA et al. Creatine supplementation improves muscular performance in older men. Med Sci Sports Exercise 2002; 34(3): 537-43.
13. Chrusch MJ et al. Creatine supplementation combined with resistance training in older men. Med Sci Sports Exercise 2001; 33(12): 2111-7.
14. Boldyrev AA et al. Biochemical and physiological evidence that carnosine is an endogenous neuroprotector against free radicals. Cell Mol Neuro 1997; 17(2): 259-71.
15. Wang AM et al. Use of carnosine as a natural anti-senescence drug for human beings. Biochem 2000; 65(7): 869-71.
16. Yuneva MO et al. Effect of carnosine on age-induced changes in senescence-accelerated mice. J Anti-aging Med 1999; 2(4): 337-42.
17. Stuerenburg HJ et al. The roles of carnosine in aging of skeletal muscle and in neuromuscular diseases. Arch Geront Geriatrics 1999; 29: 107-13.
18. Nagasawa T et al. In-vitro and in-vivo inhibition of muscle lipid and protein oxidation by carnosine. Mol and Cell Bio 2001; 225(1): 29-34.
19. Feldman HA et al. Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts Male Aging Study. Jour Clin Endo Metab 2002; 87(2): 589-98.
20. Bhasin S et al. Testosterone replacement increases fat-free mass and muscle size in hypogonadal men. Jour Clin Endo Metab 1997; 82(2): 407-13.
21. Urban RJ et al. Testosterone administration in elderly men increases skeletal muscle strength and protein synthesis. Am J Physio 1995; 269(1): 820-6.
22. Brill KT et al. Single and combined effects of growth hormone and testosterone administration on measures of body composition, physical performance, mood, sexual function, bone turnover, and muscle gene expression in healthy, older men. Jour Clin Endo Metab 2002; 87(12); 5649-57.
23. Rudman D et al. Effects of human growth hormone in men over 60 years of age. New England Jour Med 1990; 323(1): 1-6.
24. Butterfield GE. The effects of recombinant human insulin-like growth factor-1 and growth hormone on body composition in elderly women. Jour Clin Endo Metab 1995; 80(6): 1845-52.
25. Isidori A, Monaco AL, Cappa M. A study of growth hormone release in man after oral administration of amino acids. Curr Med Research and Opinion 1981; 7(7): 475-81.
26. Suminski RR et al. Acute effect of amino acid ingestion and resistance exercise on plasma growth hormone concentrations in young men. Int J Sport Nutr 1997; 7(1): 48-60.
27. Welbourne TC. Increased plasma bicarbonateand growth hormone after an oral glutamineload. Am J Clin Nutr 1995; 61(5): 1058-61.