Sleep study stresses importance of quality over quantity

Everyone has complained about poor sleep at one point or another, and a new study is looking at just how much bad shuteye can affect our bodies.

The research, published Thursday in Neuroscience, focuses on quality over quantity.

It found that people in their 30s and 40s who have more interrupted sleep were more than twice as likely to deal with memory and thinking problems a decade later.

Researchers looked at the sleep patterns of hundreds of people over six nights for a span of 11 years, starting in the early 2000s, testing their cognitive ability, including processing speed, executive function, memory, and fluency.

Overall, people whose sleep was interrupted or those who spent more time moving around had much poorer scores on all of the tests.

While the results were telling, the researchers stress “the study does not prove that sleep quality causes cognitive decline. It only shows an association.”

“Given that signs of Alzheimer’s disease start to accumulate in the brain several decades before symptoms begin, understanding the connection between sleep and cognition earlier in life is critical for understanding the role of sleep problems as a risk factor for the disease,” said study author Yue Leng, PhD, of the University of California, San Francisco.

“Our findings indicate that the quality rather than the quantity of sleep matters most for cognitive health in middle age.”

More study needed

To measure people’s activity, researchers placed wrist activity monitors on participants for three consecutive days on two separate instances, about one year apart. This calculated activity averages, with participants sleeping an average of six hours during the study times.

Those taking part in the study also tracked in a sleep diary what time they went to bed and what time they woke up, and also completed sleep quality surveys.

“More research is needed to assess the link between sleep disturbances and cognition at different stages of life and to identify if critical life periods exist when sleep is more strongly associated with cognition,” Leng said. “Future studies could open up new opportunities for the prevention of Alzheimer’s disease later in life.”