Adults with poor sleep quality in their 30s and 40s are more at risk of developing cognitive complications in the future compared to those with a good sleeping pattern, scientists say.
New research has revealed that disrupted sleep can cause middle-aged adults to experience cognitive decline later in life.
Lead author Dr Yue Leng said: “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.
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“Our findings indicate that the quality rather than the quantity of sleep matters most for cognitive health in middle age.”
During the study, a team of researchers assessed the sleep duration and quality of 526 middle-aged adults.
Each participant wore an activity monitor on their wrist for three consecutive days, and then again roughly one year apart.
In addition, each individual taking part in the study self-reported what time they went to bed and what time they woke up each day.
On average, the participants slept for around six hours each night, the study results have revealed.
They also filled in a questionnaire to rate their sleep quality with scores ranging from zero to 21.
Higher scores highlighted poorer sleep quality.
More than 40% of the participants scored higher than five, meaning they had poor sleep quality.
As part of the trial, the participants also had to complete cognitive tests so the academics could compare it with their sleep quality.
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The results show that 44 of the 175 people with the most fragmented sleep experienced cognitive decline 10 years later.
Meanwhile, only 10 people out of the 176 with the least amount of disrupted sleep experienced memory complications a decade later.
Dr Leng said: “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.
“Future studies could open up new opportunities for the prevention of Alzheimer’s disease later in life.”
The study has been published in the online issue of Neurology – the medical journal of the American Academy of Neurology.
