The conventional line of wisdom on sleep needs has long been to get a solid eight hours of sleep each night. The findings in a new study suggest that eight hours may actually be missing the mark by as much as an hour. The study, published in The Journal of the American Geriatrics Society, reports that seven hours of sleep each night is actually the optimal amount when it comes to memory function.
Researchers at Brigham and Women’s Hospital in Massachusetts included over 15,000 female nurses aged 70 and older in their study and then analyzed their memory performance and amount of sleep they received. The findings showed that both too little and too much sleep had adverse effects on the subjects’ memories later in life.
On average, subjects who got too much or too little sleep had memory function equal to someone two years older than they were. Also contributing to poorer memory function later in life was varying sleep habits by more than two hours on a regular basis.
Researchers on the study point to the importance of these findings because the amount of sleep we get is a variable within our control. With factors like genetics being out of our realm of control, finding the factors we can change for improved memory health is crucial.
This study joins a growing body of research pointing to seven hours of sleep being the superior amount for health, including a 2002 study that said over 8 hours or less than 4 hours of sleep per night was linked with a shorter life span. Still, critics of issuing precise numbers on the hours of sleep needed caution that sleep needs fall on more of a spectrum than studies like this one dictate. The bottom line is that seven hours of sleep per night is likely a good goal to aim for on average with the understanding that there will be nights you need more or less sleep from time to time.