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Walking wards off dementia

Walking may ward off dementia and mental decline, new research suggests. Older people who walk about six miles a week have more brain tissue in key areas than those who walk less, helping maintain memory and cognitive function, according to a study published in Neurology.

The researchers initially asked nearly 300 healthy volunteers ages 70 to 90 to record how many blocks they walked in a week. Nine years later, they took high-resolution brain scans of the group and found that the more the participants walked at the beginning of the study, the greater their brain volume.

On further follow-up four years later, cognitive testing showed that those who walked six to nine miles a week had half the risk of developing memory problems, Reuters reports. Brain size tends to shrink in late adulthood, which is thought to lead to memory problems.

"If regular exercise in midlife could improve brain health and improve thinking and memory in later life, it would be one more reason to make regular exercise in people of all ages a public health imperative," the study authors wrote.

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Got sleep deprivation?

Sure, we all know we're supposed to get seven or eight hours of sleep a night, but all of us skimp from time to time, getting, say, five hours one night and six hours the next. Those lost hours, though, can add up to a big sleep debt by the end of the week -- the reason so many of us feel wiped out by Friday, writes U.S. News and World Report's Deborah Kotz.

But here's a bit of good news: Researchers have found that sleeping in after a few days of missed sleep can help pay back that debt, nearly erasing any lingering sense of fatigue and mental fuzziness, according to a study published in August in the journal Sleep.

"The brain has a built-in reflex that helps you sleep deeper and longer when you're sleep deprived," says study co-author David Dinges, chief of the division of sleep and chronobiology at the University of Pennsylvania School of Medicine.

Think you're doing fine on only six hours a night? Think again. Although Dinges hears this from folks all the time, he says it's true for only a small percentage of the population. Most of us actually need seven or eight hours of shut-eye to feel 100 percent the next day.

"If you fall asleep watching TV or struggle to stay awake in a meeting," he says, "you're sleep deprived." And it's not just fatigue you feel but reduced brain function in terms of your memory, alertness, cognitive speed and reaction time. "Some of us are so used to not getting enough sleep that we've forgotten what it feels like to be fully alert," Dinges adds.

How much recovery sleep you need to feel recharged depends on how much sleep you've lost. In the study, volunteers were deprived of about three hours of sleep a night for five consecutive nights before being allowed to sleep for up to 10 hours. Those allowed to sleep a full 10 hours felt nearly, but not quite, back to normal the next day. Probably a second night of recovery sleep or an afternoon nap, would have helped them feel fully restored, says Dinges.

Also clear from the study was that getting the advised eight hours of rest after skimping all week wasn't enough to pay back the debt. Those who got that amount still felt exhausted the next day.

Compiled from News wire sources

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