According to a landmark study conducted by University College London, sleeping for more than nine hours could have serious consequences on our memory and reaction time.
The research, published in the International Journal of Epidemiology, examined 400,000 participants aged between 40 to 69 years from UK Biobank and the International Genomics of Alzheimer’s Project.
Results of a visual memory test indicated that people who slept for less than seven hours a night made 5% more mistakes per each hour less of sleep.
While those who slept for more than nine hours made even more errors with 9% per each additional hour of kip lost.
Findings suggest that an increase in sleep duration correlates with poorer reaction time and visual memory. Although there is not yet enough evidence to support associations with severe cognitive decline or dementia.
“Our study provides new evidence that both short and long sleep may have a negative impact on certain cognitive domains, such as visual memory and reaction time,” lead author, Albert Henry, explained.
“Overall, our study highlights the importance of sleep duration in relation to cognitive function,” he added. “This suggests that improving sleep habits may be beneficial for cognitive health.”
The National Sleep Foundation recommends that the average adult aims for at least seven to nine hours of sleep every night.
In order to achieve this, the organisation advises daily exercise, sleeping on a comfortable mattress and being weary of excessive caffeine consumption.
Dr Victoria Garfield, senior author, emphasises: “We would recommend that most healthy adults follow the recommendation of seven to nine hours of sleep.”