As an adolescent boy, it was the hormone responsible for the peach fuzz. As a young adult, it became the stereotypical crutch for all that pent up aggression and competition. In a man's older years, however, testosterone may be the key to male vitality.
A recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM) found that higher levels of testosterone are associated with reduced lean muscle mass loss in older men, especially those who lost weight.
Researchers measured both the body composition and sex steroid hormones of 1,183 ambulatory men aged 65 years and older. Subjects completed series of exercises that assessed walking speed, lower extremity power, grip strength, and the ability to rise from a chair without the use of arms and repeated the same series of exercises 4 and half years later.
In a press release from The Endocrine Society, Erin LeBlanc, MD of Kaiser Permanente Northwest, the study's lead author, discussed the findings explaining, "Our study finds that men, aged 65 years and older, with higher testosterone levels lost less muscle mass, especially in their arms and legs, than men this age who had lower testosterone levels." Furthermore, 40 percent of men who lost more than 4.4 pounds showed considerably less lean mass decline at higher baseline testosterone levels. Medical Xpress reports that men with higher testosterone levels before they lost weight also retained more leg function and found it easier to stand up from a chair than men with lower testosterone levels before losing weight.
In addition to maintaining sex drive and sperm production, testosterone in men also helps maintain bone density, fat distribution, and muscle strength and mass. According to the Mayo Clinic, testosterone levels peak during adolescence (hello, puberty) and early adulthood (that growth spurt your high school self never thought would come), and gradually declines after the age of 30 at a rate of typically 1 percent a year. "Our study adds evidence to the growing body of literature that suggest higher levels of endogenous testosterone may be favorably associated with some key components of healthy aging in men," LeBlanc continued in the press release.
The full article, "Higher testosterone levels are associated with less loss of lean body mass in older men," appears in the December 2011 issue of JCEM.