Researchers say that there is such a thing as too much sleep. Just as a person that sleeps too little, sleeping too much can cause a person to be sleepier. One study has shown that a person that sleeps more than the suggested six to eight hours a night does just as poorly as a person that sleeps less than six hours a night on a cognitive reasoning test.
According to “Sleep Your Brain Young,” sleeping for more than eight hours a night can cause your brain to age prematurely. In addition, consistent sleep patterns of approximately seven hours of sleep a night can help reduce the regular cognitive decline that happens to us as we age. In this specific study, men and women were tracked over the course of five years and were consistently asked to perform memory, vocabulary, and logic tests. The study suggested that those who did not get enough sleep showed a loss in brain function that was like aging four to seven years.
People generally sleep less as they age, so maintaining six to eight hours of sleep consistently can prevent the natural memory loss that happens. While people may battle insomnia or other sleep disorders, quality sleep is essential to keep the brain young. When people sleep for longer than the suggested eight hours, their cognitive functioning may be lower because although they may be in bed for a long period of time, the quality of their sleep is not necessarily the best.