Sleep Too Much or Too Little

Are you getting your seven hours?

Although tradition recommends eight hours’ sleep each night, research is coming more and more to the conclusion that seven hours is best, and eight or more can be too much, causing as many problems as too little sleep.

A recent study, using data from the U.K. Biobank, a national database of individuals in the U.K. that includes brain imaging, mental health questionnaires and cognitive assessments found that both insufficient and excessive sleep was correlated with cognitive decline and increased incidence of mental health problems including anxiety, depression, and mania.

Impaired cognitive function, including lower performance on tests including pair matching, trail making, prospective memory, and reaction time was found in people who had either too little or too much sleep.  Further analysis of the results found that the optimum sleep time both for cognitive performance and good mental health was approximately 7 hours.

Changes in brain structure were also found, noting a decreased cortical volume in brain regions associated with cognitive processing and memory.  Again, these changes were found both in people who got too little sleep as well as those who got too much.

Need for sleep doesn’t change with age

In the past, it has been thought that the need for sleep decreased with aging, but this large cohort database found no support for that assumption.  At all ages, seven hours’ sleep appears to be optimal.  Further research is needed to discover what, if any, effect disturbed or interrupted sleep patterns have on these findings, since this study looked only at length of sleep, not “sleep hygiene” as researchers call the undisturbed pattern of healthy sleepers.

In our practice, we have consistently found that sleep is one of the most important factors in achieving and maintaining mental health and healing, and we spend a lot of time working with patients on various aspects of sleep and insomnia.  Sleep hygiene includes using the bed only for sleeping (and sex), and getting up if not feeling sleepy.  Just lying on the bed, tossing and turning doesn’t help and can be detrimental in the long run.  The best practice we have found is to set regular routines and follow them as much as possible.  Allowing your system to settle into a base pattern and not trying to get too much sleep are important disciplines for overcoming insomnia.


For more on sleep and insomnia:

Bedtime procrastination

Daytime anxiety impacts insomnia

Sleep and temperature

No Melatonin