EXERCISE REVERSES AGING IN HUMAN SKELETAL MUSCLE

A resistance training exercise program for healthy adults over age 65 was found to reverse aging at the cellular level in a study by McMaster University in Hamilton, Ontario, Canada; the Buck Institute for Age Research, based in Novato, California; and the Center for Genetics, Children's Hospital Oakland Research Institute, Oakland, California. The study involved before and after analysis of gene expression profiles in tissue samples from 25 healthy older men and women who underwent 6 months of twice-weekly resistance training, compared with a similar analysis of tissue samples from 26 younger healthy men and women. Tissue samples were taken from the thigh muscle. The gene expression profiles involved age-specific function of the mitochondria, which act as the "powerhouse" of cells. Multiple studies have suggested that mitochondrial dysfunction is involved in the loss of muscle mass and functional impairment commonly seen in older people. The study was the first to examine the gene expression profile, or the molecular "fingerprint," of aging in healthy disease-free humans. The study participants were matched in terms of diet and exercise; none of them took medication or had diseases that can alter mitochondrial function. The 6-month resistance training was done on standard gym equipment. The twice-weekly sessions were an hour long and involved 30 contractions of each muscle group involved, similar to training sessions available at most fitness centers. Results showed that in the older adults (average age 70), there was a decline in mitochondrial function with age. However, exercise resulted in a remarkable reversal of the genetic fingerprint back to levels similar to those seen in the younger adults (average age 26). The study also measured muscle strength based on knee flexion. Before exercise training, the older adults were 59% weaker than the younger adults, but after the training the strength of the older adults improved by about 50%, so that they were only 38% weaker than the young adults.

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