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Sleep 7 or 8 hours

Is 7 the new 8 when it comes to getting enough sleep? (photo credit:BigStockPhoto.com)

If I asked you how much sleep you are supposed to get every night, odds are you would answer ‘8’ which has been the standard recommendation from the medical community for as long as most of us can remember.  But it turns out that we may not need quite that much sleep after all, at least according to the results of several new studies.

Sleep scientists are urging the sleep science community to adopt new guidelines that are more aligned with the wealth of recent research which indicates that 7 hours is the ideal amount of sleep, not 8 as previously believed.  According to the research results, cognitive function and health outcomes are optimal when a person sleeps for 7 hours a day.

The new wealth of research has also shown that while sleeping less than that amount can have very real consequences in both the short and the long term, sleeping too much is also hazardous to your health.  People who get less than 7 hours of sleep are more likely to be in an automobile accident or develop several chronic diseases, and are likely to experience cognitive deficits after skipping some sleep on a single night.  Those who get too much sleep seem to have an increased risk for diabetes, cardiovascular problems, and death.

The new research indicates that from a disease and longevity standpoint, 7 hours is the perfect amount of sleep.  Those who regularly sleep for 7 hours have the lowest mortality and morbidity rates.

In response to all the new research findings in the field of sleep science, including this one, the Centers for Disease Control is funding a committee to review all the available literature and make new recommendations about sleep and health sometime next year.

Some of the research that may lead to a change in this long standing recommendation includes:

  • A study from the University of San Diego that used data from more than a million people that were participating in a cancer study.  Findings indicate that people that slept between 6.5 and 7.4 hours a night have a lower rate or mortality than people who slept more or less than that.
  • Another study that was published in the journal Sleep Medicine involved recording the sleep patterns of 450 elderly women using an actigraph worn around the wrist.  The findings showed that women who sleep less than 5 hours a night or more than 6.5 hours a night during that study were more likely to die in the next 10 years than those who sleep between 5 and 6.5 hours.

While not all experts agree that sleeping too much is as dangerous as sleeping too little, the research clearly indicates that we may need to change our thinking about what it means to get a good night sleep.  The challenge now is to understand the mechanisms behind these findings, as they can pinpoint an association but more work needs to be done to prove and understand causation, or why getting 7 hours of sleep seems to be so important to overall health.