Not long ago most people, including scientists, were convinced that physical aging was a slow but inevitable march to frailty. In the early 70's studies showed that as early the age of late 30's some people start to lose muscle mass, a process known as sarcopenia. From middle age muscle mass was declining in most people by 1 per cent every year. Strength plummets from this.
Sarcopenia is widely recognized as one of the primary causes of frailty in older people and the accompanying loss of independence. Someone who is frail and whose muscles have shriveled can't rise from a chair or heft grocery bags. He or she can't live alone.
Scientists also found that people's general fitness, as measured by the ability of their respiratory and circulatory systems to deliver oxygen to labouring muscles, fell by 10 per cent per decade after the age of 40. That loss is a considerable dip in lung power and is considered a primary reason many middle -aged people reduce exercise or quit altogether. The effort feels increasingly hard.
But all is not lost! All these studies were of volunteers who were inactive. Everything changed when scientists began looking at volunteers who willingly and frequently moved.
A study of participants in the New York City Marathon found that in the early 1980's participation of the 50+ age category was negligible. Authours of the study noted "few 60 year old men, women or their doctors would have considered it possible for someone that age to run 26 plus miles (or 42 kilometres)." However from the 1980's to 2000 while the number of male runners in their 20's grew 25 per cent, the numbers in their 50's grew 78 per cent. As well the average finishing time improved by 30 minutes, improving only 2 minutes for men in their 20's.
As Dr. Tanaka, a professor of physiology at the University of Texas and an expert on ageing athletes, says, "A great deal of the physical effects that were once thought were caused by ageing are actually the result of inactivity."
Recently researchers from the Canadian Centre for Activity and Ageing reported that when they microscopically examined the leg muscles of older runners, most past 65, they found that the aging runners muscles were densely packed with motor units. A motor unit is the control unit of a functioning muscle. The more motor units in a muscle, the faster and more fully that muscle can contract; the healthier and stronger it is. Too few motor units is the beginning of sarcopenia. The studied runners had as many motor units as inactive 25 year olds.
Additionally scientists were struck by one particular aspect of their older runners. "They looked much younger than sedentary control subjects of the same age," said Dr. Werner, the studys lead authour.
Even more striking! When the scientists examined the white blood cells from both young inactive subjects, those middle-aged and those exercising at age 65+. They found the young people's white blood cells 40% healthier than those inactive in middle age. While they were only 10% healthier than those exercising later in life.
Exercise, Dr. Werner says, "at the molecular level has a strong antiaging effect."