Walking, weight lifting, flexibility training and other forms of exercise can help seniors avoid disabilities normally associated with aging and even reverse the aging process itself, a team of scientists has concluded.

Some decline in physical ability is an inevitable result of normal aging, but inactivity can hasten this decline and result in all-too-rapid rates of muscular atrophy, decreased endurance and loss of flexibility and balance, according to Kyriakos S. Markides, Ph.D., and colleagues at the University of Texas Medical Branch in Galveston.

Reporting in the winter issue of "Behavioral Medicine," the researchers cite numerous studies that demonstrate the benefits of exercise on the aging process, including:

A walking program for people in their 70s that reversed 22 years of declining lung capacity in 22 weeks. The capacity of lungs to absorb oxygen normally declines an average of 1 percent a year after age 40; those in their 70s recaptured the lung capacity they'd had in their 50s.

A 12-week weight resistance program that more than doubled the leg muscle strength of some participating women 64 years and older.

A 12-month resistance training program for men and women that increased their muscle strength by 30 percent to 100 percent in the first three months, after which point they reached a plateau and did not continue improving.

A study in which people who exercised by walking several days a week decreased their risk of disability and improved their ability to walk distances, climb stairs, stoop, crouch, kneel and carry objects. The risk of disability decreased by one-third for whites and two-thirds for African-Americans.

Older people not only can slow down aging by maintaining regular physical activity but also prevent chronic conditions, said Markides and colleagues.

A sedentary lifestyle is the most prevalent modifiable risk factor for coronary artery disease, far exceeding hypertension, smoking and high cholesterol. In one study, 184 adults aged 60 and older were randomized into three groups: long-term exercise, short-term exercise and a control group. At the end of two years, both exercise groups showed a decreased rate of new cardiovascular diagnoses compared to the control.

The researchers report that patients who already have coronary artery disease can reduce their risk of death from a cardiac event by 20 percent to 25 percent if they exercise, and even lower the severity of some risk factors for heart attacks, such as hypertension, obesity, high cholesterol and diabetes.

A sedentary lifestyle also increases the risk for hip fractures, according to the researchers. In one study, women who spent less than four hours a day on their feet had nearly twice the risk of hip fractures as their more active counterparts.

Copyright 1999 Health Resources Publishing