Active Low-Carber Forums - "EXERCISE REDUCES THE ACHES OF AGING"

WASHINGTON (AP) -- The weight goes on but the muscle comes off. The heart rate falls, bones get weak. Aging is one physical frustration after another.

But experts say it doesn't have to feel so bad.

Many of what are thought to be the infirmities of age really are the results of inactivity, they say. And even though exercise can't make the old young again, regular activity can lead them back to a more youthful lifestyle.

"It is well known that being more fit and more lean is associated with better health," said Johns Hopkins researcher Kerry J. Stewart. "We showed that being more fit and having less fat also is associated with better health and mood."

Stewart and colleagues presented their findings May 30 at the American College of Sports Medicine's annual meeting in Baltimore, Maryland. The researchers evaluated 14 men and 22 women ages 55 to 75 with mild high blood pressure who signed up for an exercise program.

Researchers assessed the participants' fitness on treadmill testing, checked muscle strength on weight lifting exercises, and measured body fat. The participants also completed questionnaires about mental health and mood.

Those who were in better physical shape also were less tired, less depressed, less angry and in overall better moods. Participants with greater proportions of body fat were more depressed and angry, and less happy.

"We were able to apply scientific methodology, and somewhat confirm people who are physically healthier report better moods and less anger," Stewart said.

People who are in better shape are happier probably because they can do more, Stewart said. "They are more engaged in life, and have a better self-image," he said.

An article in IDEA Health and Fitness Source, a fitness professional journal, reviewed the physical losses that come with age and the ways in which exercise can minimize them.

The body's ability to use oxygen slips by about 10 percent a decade after age 30, said the article. This physiological change probably is due largely to age-related decreases in heart function, especially to a drop in the amount of blood that the heart can squeeze out in each contraction, it said.

A lack of aerobic exercise such as walking, running and biking makes the age-related loss greater, piling the effects of lethargy onto the results of simply growing older.

But becoming more physically active can bring big improvements in endurance. In one study of healthy men ages 60 to 70, the ability to use oxygen rose 38 percent after high-intensity cardiovascular training, the article said.

In today's sedentary society, drop in endurance may not be noticeable to older people unless they suddenly have to run. But they do notice their loss in strength.

That's not true of the ability to lift things. Older people who, as young parents, had toted their own toddlers with ease can be shocked to discover they cannot lift a grandchild. But muscles lose strength at a rate of about 12 to 14 percent per decade after age 50, the report said.

The losses in strength are probably due to shrinkage in muscle size. Again, however, training can make big changes. Two months of weight training can reverse as much as two decades of muscle shrinkage and strength loss, the article said.

Bones also weaken, as the normal honeycomb structure crumbles into large gaps. Women lose bone at a rate of 2 to 3 percent a year after menopause, and men lose bone at a rate of about 1 percent a year after age 50, the article said.

Bone responds to the stress of exercise by laying down more mineral deposits. Although exercise alone doesn't make up for the losses, it can help to slow the rate of loss -- and sometimes bring the deterioration to a halt.

Weight training is the most effective exercise format for bone density, the article said. Walking, jogging and other aerobic exercise can help, provided the movements are forceful enough to put some stress on bones.

Metabolism slows with age. Resting metabolic rate falls by about 10 percent from early adulthood through retirement age, and drops even more after 65, the article said. With calories being used at a lower rate, fat builds up -- unless people eat less, which they commonly don't.

Inactivity and fat bring higher risks of diabetes and cardiovascular disease, which fat-burning aerobic exercise can reduce. In one study, vigorous training in 60- to-70-year-old men and women led to significant drops in fat levels after 9 to 12 months, the review said.

Copyright 2001 The Associated Press.