I do not say this lightly – the benefits of resistance training (also know as weight- or strength-training) are so extensive, and so well-established, that in my opinion family doctors should prescribe weight training to all of their patients.  Did you know that 80 percent of people over the age of seventy-five cannot lift ten pounds?  This is what a bag of groceries, or a new grandchild, weighs.  The loss of muscle, called sarcopenia, accelerates in men after about age 40 and in women after menopause.  All of us lose muscle mass as we age, but individuals who start out with more muscular strength will not suffer the ill effects of sarcopenia like those who start out with less.  This is not an issue of aesthetic appearance, but an issue of quality of life! Resistance Training Can Reverse the Aging Process A study by Melov and colleagues (2007) explored whether resistance training affects some of the gene expressions associated with muscle aging, thus reversing the aging process.  They compared two groups: active older adults (average age 68), and inactive younger adults (average age 24).  They felt that choosing active seniors and an inactive younger group would help them look at the effects of aging, rather than simple inactivity.  Both groups performed supervised strength training exercises at a fairly high intensity. Before starting the program, and after 26 weeks, both groups underwent muscle biopsies from which RNA could be extracted.  After 26 weeks, the researchers identified 170 age- and exercise-associated genes showing a reversal of their gene expression.  The most amazing thing about their results is that both the trained groups – older and younger – showed similar characteristics in gene expression!  Another significant finding was that mitochrondrial impairment (mitochrondria are the energy-producing cells of muscle fibres – their “furnace”) – normally seen with inactivity – was reversed in response to the six months of weight training. It is well-known that long-term resistance training is associated with a lower risk of age-related disease morbidity and mortality, and this study may help us understand why this is the case.