Altered sleep pattern affects brain aging

Sleeping less than six or more than eight hours a night is associated with a decline in brain function in the middle-aged adults, a new study says.

A 5-year study of more than 5,000 middle age people showed that any change in sleep duration affects the participants' performance on several cognitive ability tests.

According to the findings, half of women and 18 percent of men who sleep less than six hours per night score lower on three out of the six evaluations and experience declined ability in concentrating and communicating.

Moreover, 7 to 8 percent of people who usually sleep more than eight hours per night score lower on five out of six cognitive tests, the study found.

The magnitude of the mental decline is equal to being four to seven years older, wrote researchers from the University College London Medical School.

In fact, women who slept seven hours per night, followed by those who had six hours of sleep, had the highest score for every cognitive test. For men, cognitive function was similar in those who reported sleeping six, seven or eight hours.

However, less than six hours or more than eight hours of sleep were associated with lower test scores, researchers concluded in their report published in the journal Sleep.

"Sleep provides the body with its daily need for physiological restitution and recovery. While seven hours a night appears to be optimal for the majority of human beings, many people can function perfectly well on regular sleep of less or more hours," said lead author Jane Ferrie.

"There is an expectation in today’s 24-hour-a-day society that people should be able to fit more into their lives," she added. "The whole work/life balance struggle is causing people to trade in precious sleeping time to ensure they complete everything they feel is expected of them. Our study suggests that this may have adverse effects on their cognitive function."