There’s yet more encouraging news to report in the effort to keep people active and mobile as they grow older. It turns out that exercise isn’t just good for your body; it’s good for your genes. In an article published in May 2007, entitled “Resistance Exercise Reverses Aging in Human Skeletal Muscles,” Simon Melov and other researchers determined that older individuals who engaged in resistance training twice a week for six months had skeletal muscles that were not only stronger, but actually genetically younger.

At the most basic level, this is how it works: In younger people, the genes that control the health of muscle cells and regulate the muscle’s use of energy express themselves at optimal levels. As we age, some of these genes get turned up (up-regulated) and some of these genes get turned down (down-regulated). The genes that are up-regulated, or become more expressed with age, are those involved with cell repair, DNA repair, and cell death. The genes that tend to get down-regulated, or become less expressed with age, are those associated with a part of our cells called the mitochondria, which is responsible for efficiently turning nutrients into energy.

Based on these changing levels of genetic expression, it is not surprising to find that skeletal muscle in older people exhibits more cell death and mitochondrial dysfunction as compared to younger people. Without exercise, this leads to muscle weakness and impairment, and eventually muscle atrophy, known as sarcopenia.

Melov and his colleagues designed their study to determine whether muscle decline was reversible all the way down to the genetic level. To this end, skeletal muscle of a group of younger, healthy adults and a group of healthy, active, disease-free, older adults was acquired from all subjects. The muscle in both groups underwent genetic expression profiling before the older group embarked upon a resistance exercise program, and then again at the conclusion of the program.

The study identified 596 genes in the skeletal muscles that were expressed differently in older and younger individuals. Of these 596 age related genes, 179 were impacted by the resistance exercise performed by the older group.

At the end of the study, the findings were striking: As a result of the six-month resistance exercise program, the genetic profile of the skeletal muscles in the older individuals substantially resembled the genetic profile observed in the younger group. The expression of the 179 age-related genes impacted by the exercise had returned to younger levels!

The leg muscles of the older subjects were also 50 percent stronger than before training, but more significantly –– and because of the genetic changes –– the usual age-induced impairments in cell repair activities and mitochondrial function were reduced. The implications of this study are potentially enormous, since it is estimated that only about 12 percent of the population over age 65 engages in resistance exercise twice a week.

For the complete study, see:
Melov, Simon, Mark A. Tarnopolsky, Kenneth Beckman, Krysta Felkey, and Alan Hubbard (2007). Resistance exercise reverses aging in human skeletal muscle. PLoS ONE, 5, 1–9.

link to complete study