A prospective cohort study of health and endocrine functioning in randomly selected men with a baseline visit (T1, 1987-1989) and two follow-up visits (T2, 1995-1997; T3, 2002-2004) was conducted.


Participants included 1667 men aged 40 to 70 at baseline; follow-up was conducted on 947 (57%) and 584 (35%) at T2 and T3, respectively.


There were substantial declines in total serum T and FT levels associated with aging alone. However, many health and lifestyle changes were associated with accelerated decline.

When not taking health status into consideration, declines of -14.5% (95% confidence interval, -16.3% to -12.6%) in total T and -27.0% (-29.1% to -5.0%) free T per decade of aging.

The corresponding estimated trends including only subjects who were apparently healthy were less sharp; among such subjects, declines of -10.5% (range -14.0% to -7.0%) in total T and -22.8% (-26.9% to -18.7%) in free T per decade of aging.

A 4 unit increase in body mass index (BMI), for example a man 5'8 (1.75 m) gaining weight from 176 lb (80kg, BMI 26) to 202 lb (92 kg, BMI 30), was associated with a decline in total testosterone level comparable to that associated with approximately 10 years of aging.


This study [4], and many others [5-8], show that both chronological aging and changes in health and lifestyle factors are associated with declines in testosterone levels. Co-morbidities and lifestyle influences may be as strongly associated with declining testosterone levels as is aging itself.

Another study confirmed these finding by showing that the effect of increasing body fat and waist size on lowering testosterone levels is more substantial, compared with that of age. [5] This later study also demonstrated that body fat / waist size is the most important determinant of the differences seen in total testosterone levels [5], regardless of age. [9]

Accumulating research data supports the major impact of body fat/waist size in determining testosterone levels. A systematic review and meta-analysis which found that weight loss reverts obesity-induced secondary hypogonadism.[10] However, the amount of weight loss required is large and very hard for most men to achieve and sustain. Nevertheless, healthy lifestyle habits should be given more attention as a strategy to prevent development of hypogonadism.

The sharper decline in testosterone levels in people with poor health, among whom obesity, metabolic syndrome, diabetes and cardiovascular disease is common, indicates that a substantial proportion of the apparent aging effect is attributable to changes in health status. Thus, the age-related testosterone decline can be partially prevented and/or slowed down by adherence to a healthy lifestyle incorporating a sound diet and regular exercise.


  1. Harman, S.M., et al., Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab, 2001. 86(2): p. 724-31.
  2. Feldman, H.A., 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. J Clin Endocrinol Metab, 2002. 87(2): p. 589-98.
  3. Morley, J.E., et al., Longitudinal changes in testosterone, luteinizing hormone, and follicle-stimulating hormone in healthy older men. Metabolism, 1997. 46(4): p. 410-3.
  4. Travison, T.G., et al., The relative contributions of aging, health, and lifestyle factors to serum testosterone decline in men. J Clin Endocrinol Metab, 2007. 92(2): p. 549-55.
  5. Wu, F.C., et al., Hypothalamic-pituitary-testicular axis disruptions in older men are differentially linked to age and modifiable risk factors: the European Male Aging Study. J Clin Endocrinol Metab, 2008. 93(7): p. 2737-45.
  6. Yeap, B.B., et al., Healthier lifestyle predicts higher circulating testosterone in older men: the Health In Men Study. Clin Endocrinol (Oxf), 2009. 70(3): p. 455-63.
  7. Camacho, E.M., et al., Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study. Eur J Endocrinol, 2013. 168(3): p. 445-55.
  8. Haring, R., et al., Clinical correlates of sex steroids and gonadotropins in men over the late adulthood: the Framingham Heart Study. Int J Androl, 2012. 35(6): p. 775-82.
  9. Goncharov, N.P., et al., Testosterone and obesity in men under the age of 40 years. Andrologia, 2009. 41(2): p. 76-83.
  10. Corona, G., et al., Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis. Eur J Endocrinol, 2013. 168(6): p. 829-43.