How Much Sleep Do You Need?

| Posted On Aug 24, 2016 | By:

sleep - shutterstock_270278747I get asked this question several times a day by my patients, and for many of us, the answer is, “not nearly enough.”

The National Sleep Foundation recently assembled 18 experts and sifted through 320 research articles. Based on this work, they recommended 7-9 hours of sleep per night for the average adult (for seniors, they recommended 7-8 hours). The American Academy of Sleep Medicine also came out with a consensus paper and recommended that adults sleep at least 7 hours per night.

How are we doing? Unfortunately, Americans seem to be going in the wrong direction: in 1942, we slept 7.9 hours a night; today, we only get an average of 6.8 hours of sleep a night. According to a 2013 Gallup poll, about 40% of us get less than the recommended amount of sleep.

There is no doubt that we are a sleep-deprived population. Artificial light, electronic “screens” that connect us to whatever we want whenever we want it, and the lengthy time demands of work and family – these factors have all made sleep much more elusive for many of us.

Sleep deprivation leads to many health consequences including slow cognitive processing, inattention, memory problems, diabetes, and obesity. Furthermore, several large studies have shown that sleeping 5 or less hours increases your risk of fatal and non-fatal heart attacks by 45% and death by 15%.

But say you typically go to bed at 10 pm and wake up at 5 am.  That’s 7 hours, right? In actuality, it’s probably not.

Most people are not aware that when we talk about “sleep,” it needs to be defined in terms of what we call “sleep efficiency.” Sleep efficiency is the percentage of time you were actually asleep while in bed. We consider a good sleep efficiency to be 85% (meaning 85% of the time you spent in bed, you were actually asleep), while 90% is excellent. Sleep efficiency is never 100%; it might take you some time to fall asleep and during the night you likely wake up.

Using our 10 pm to 5 am example, and applying an 85% sleep efficiency, you are likely only sleeping 6 hours, while 1 hour was spent awake (either at the start, the middle, or the end of your sleep time). With a 90% sleep efficiency, you got 6.3 hours of sleep.

“Unplugging” from electronic devices earlier or more fully in the evenings is one good way to improve your ability to get the recommended amount of sleep. Along these lines, there was an interesting research study published in 2014. As part of a television program, 5 adults lived in a Stone-Age settlement without electricity, running water, or any modern amenities. Before the study, participants were sleeping 5.7 hours a night. During the study, they slept 7.2 hours a night.

For other ideas on how to improve your sleep, check out this article, “Sleepless Nights: How to Help with Insomnia.”


Print Friendly, PDF & Email

About Dr. Karim Awad

Dr. Karim Awad joined the practice in 2012 and currently sees patients at our Harvard Vanguard Kenmore practice. Dr. Awad is board certified by the American Board of Psychiatry and Neurology. He attended medical school and also completed his internship at Tulane University in New Orleans. He completed his residency at Harvard Combined Program/Massachusetts General Hospital here in Boston.