As people grow older, many worry that if they exercise they may do more harm than good and perhaps even injure themselves.
But that fear is simply not true even in the case of the very old, says Robert Mazzeo, a professor in the department of kinesiology and applied physiology at the University of 欧美口爆视频 at Boulder.
"Remaining sedentary is more dangerous than any physical activity," says Mazzeo, who also is chairman of the American College of Sports Medicine committee, which recently reported on the issue.
The benefits of regular exercise, even for people into their 80s and 90s, are enormous, he says, and lead to improved overall health, greater independence and ultimately a much better quality of life in old age.
Mazzeo says regular cardio-vascular exercise 聳 such as walking, running, cycling, swimming, rowing, skipping or aerobic classes 聳 and strength training become increasingly important as people grow older.
From the age of about 50 onward there is a steady decline in the body聮s muscle mass which, if left unchecked, can lead eventually to increasing frailty and loss of ability to perform even basic functions such as climbing stairs or working around the house.
With aging there also is a corresponding increase in the likelihood of falling and breaking bones, high blood pressure and excessive weight gain plus greater risk of medical conditions like diabetes, stroke and heart disease.
According to Mazzeo, improving endurance fitness and body strength through as much regular exercise as possible will counter those effects of aging and deliver a longer and better quality life.
"Strength training helps offset the loss in muscle mass and strength typically associated with normal aging," say the guidelines on exercise for older adults, which Mazzeo and his committee wrote for the American College of Sports Medicine.
Studies have shown that older men and women can achieve two and threefold increases in muscle strength in as little as three to four months. Strength training also is seen as an important way to increase levels of physical activity among the elderly.
"Additional benefits from regular exercise include improved bone health and, thus, reduction in risk from osteoporosis; improved postural stability, thereby reducing the risk of falling and associated injuries and fractures; and increased flexibility and range of motion."
Research also reveals that exercise reduces body fat and cholesterol levels, both heart disease risk factors, and most likely boosts the efficiency of the immune system.
Mazzeo and his colleagues also are convinced there are a range of psychological and less tangible benefits such as alleviation of depression symptoms, improved memory and attention, and heightened feelings of self confidence, control and self worth.
However, he does advise those who have been sedentary all their lives to consult a doctor before starting exercise to be sure there are no hidden medical problems.
Similarly, the more elderly and frail should concentrate on building muscle strength before attempting intense exercise. "Aerobic conditioning should follow strength and balance training which is, unfortunately, the converse of what is done today."
The guidelines note that in 30 years, 70 million Americans will be age 65 and older while the fastest growing segment of the population will be those over 85.
"The benefits associated with regular exercise and physical activity contribute to a more healthy, independent lifestyle, greatly improving the functional capacity and quality of life in this population."