(from the New York Times, March 2, 2011)
Researchers at McMaster University in Hamilton, ON are attempting to answer the question, “Can Exercise Keep You Young?” Dr. Mark Tarnopolsky was surprised when he and his students discovered that exercise kept a strain of mice from becoming grey prematurely. They studied mice whose cell mitochondria were altered to lack the inherent repair mechanism so that they aged prematurely. Things like muscle shrinkage, decrease in brain volume, fur loss and greying, enlarged hearts, frailty, and even shrivelling gonads were all markers of an early aging process in the mice. However, they divided these genetically altered mice into two groups, a sedentary group and an exercising group. At 8 months (or about age 60 in human terms), the sedentary group showed the age-related markers and were all dead before they reached their 1st birthday. The exercising group on the other hand, remained youthful at 8 months. They maintained their dark fur, which was still full, their muscle mass had only shown a slight decrease as did their brain volume, their balance was good, and even their hearts were normal size as were their gonads. Even though they still had the genetic mutation that inhibited mitochondrial repair, they had more mitochondria and less damage than their sedentary cousins. All were still alive at age 1.
What was their key to the fountain of youth? A vigorous exercise regimen. They ran on a wheel for 45 minutes, 3X per day beginning at their 3rd month. This is the human equivalent of running a 50-55 minute 10K. Thus the exercise was of a cardio or aerobic nature and considered much more vigorous than what the general recommendations for exercise are. The researchers admitted that there is probably a threshold of exercise that needs to be reached in order to slow down physiological aging and this study was not meant to determine that threshold. Still, they believe that even following a less rigorous regimen humans can still reap some benefit. Besides prior studies has shown an improvement in mitochondrial function in older adults who did weight training at a moderate level. As Tarnopolsky has said, “Anything is better than nothing.” “If you havent been active in the past”, he continued, “start walking five minutes a day, then begin to increase your activity level”.