You're never too old to exercise

Exercise not only loosens the muscles and clears the mind, it also makes the arteries more stretchy and less prone to hardening.

Pittsburgh University researchers say that even people in their 90s have shown beneficial effects from moving around in their homes and neighbourhoods.

Rachel Mackey, who studies the patterns of heart disease, said it was not so much conscious exercise as generally being active that seemed to confer the benefits.

"Just moving around the house was associated with less arterial stiffness," said Ms Mackey, who led the study.

"The take-home message is you don't have to expect that you are going to function terribly in old age."

Many studies have shown that as people get older, their arteries get stiffer.

This condition, known commonly as hardening of the arteries, is separate from the process that causes blocked arteries, but it can also lead to heart disease and death.

"Most people don't understand that arterial stiffness is something distinct from the building-up of plaque in the arteries," said Ms Mackey.

"The building-up of plaque clearly is related to cholesterol and other fats in the blood."

Her team looked at 356 men and women aged between 70 and 96.

Their volunteers were asked questions about how active they were and whether they had exercised - from mowing the lawn to dancing - in the past two weeks.

The researchers measured the stiffness of their arteries with a technique called pulse wave velocity.

"When the heart beats, it creates a pressure wave and we are measuring those pressure waveforms," said Ms Mackey. "They travel faster in a stiffer artery."

To their surprise, the researchers found that the oldest people did not necessarily have the stiffest arteries.

Those who reported the most activity had the stretchiest arteries.

This was confirmed by some hard scientific measures - waist circumference, blood glucose levels and resting heart rate.

People with bigger waists tend to be overweight and have more heart disease, as do those with higher glucose levels, which can progress to diabetes.

Usually, the higher someone's resting heart rate, the worse physical shape he or she is in and the higher the risk of heart disease.

"I think both diet and exercise matter," said Ms Mackey.

Exercise can affect the walls of the arteries in two ways.

For one, the walls just wear out the more the heart beats. Although the heart rate goes up temporarily during activity, people who are frequently active have a lower overall heart rate.

And exercise lowers glucose levels. Glucose, or blood sugar, can chemically interact with the walls of the blood vessels, damaging them and causing them to stiffen.

"This also explains why slender people can have heart disease," said Ms Mackey.

"The point is that you could probably eat pretty well and not be a fat person but be very sedentary and still end up with diabetes and stiff arteries."

The team's findings are reported in the American Journal of Hypertension.

- REUTERS

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