Most of us have been told that eight hours of sleep is the magic number for good health, but now it turns out that eight may not be enough. Sleep expert Daniel Gartenberg, PhD, says 8.5 should be the new number on Americans’ minds.

Why the extra half hour? Because you’re not actually sleeping for a full eight hours just because you’re in your bed for that amount of time. Most of us don’t fall asleep the minute our heads hit the pillow (if you do, it could be a sign that you’re sleep deprived), and it’s also pretty natural to wake up for a bathroom break at least once per night, says Dr. Gartenberg. So, you might be spending only 90% of your time in bed asleep. Even for a healthy sleeper, eight hours in bed may only net 7.2 hours asleep. Tuck yourself in a half-hour earlier, and you can up your nightly snooze to 7.65 hours—still not a full eight, but better than the 6.8 hours of shut-eye that the average American gets.

Even better: For most people, spending an extra half-hour in bed can eliminate the AM groggy feeling known as sleep inertia. You may actually wake up refreshed and sharp—imagine that!

Of course, different people have different sleep needs, and some do well on less sleep than others. But remember that even though research shows that seven hours is the minimum, you’d need to be in bed for 7.5—that extra half-hour—to get close to spending seven hours asleep…in bed for 7 hours to spend close to 6.5 hours asleep…and so on.

Need more reasons to spend more time in bed? Here are a dozen…studies have linked too little sleep with…

  • Weight gain and obesity
  • Metabolic syndrome
  • Diabetes
  • High blood pressure
  • Heart disease
  • Stroke
  • Increased risk of Alzheimer’s disease
  • Increased risk of death
  • Impaired immunity
  • Increased pain
  • Impaired work performance
  • Greater risk of accidents


To hit your sweet spot for sleep time and good health…

Figure out how much sleep is right for you. Try this: The next time you’re on vacation (or have a weekend without early-morning plans), go to bed at the same time each night and keep track of when you wake up naturally without the usual external stressors such as work and cues like alarm clocks. This should give you a good indication of how much sleep your body craves.

Rebalance your light exposure. Increasing your light exposure when you wake up—trying a morning outdoor walk—can make it easier to rise and shine going forward. In the evening, cut back on light exposure, especially the blue light from your electronic devices, at least one hour before turning in so it doesn’t stimulate your brain and make it harder to fall asleep.

Don’t let noise hurt your sleep. Just as light can mess with your sleep, so can sound. Even something as innocuous as the central air clicking on and off can interfere with some people’s slumber. Leaving a fan on overnight or using a white noise machine can help. There are various apps for iOS and Android that provide soothing masking sounds, as well. One that Dr. Gartenberg created for iOS called Sonic Sleep Coach has a feature called “Acoustic Cushion” that uses pink noise and nature sounds to block out disruptive sound.

If you sleep with a partner, try separate blankets. You’ve likely heard that the ideal room temperature for sleep is between 68 and 72 degrees F (some sleep organizations, such as the National Sleep Foundation, peg it much lower at between 60 and 67 degrees F) but you and your partner may not be equally comfortable at the same temperature. If you get too cold or too hot, your body will shift out of the restorative REM stage and into a lighter sleep stage to help regulate your body temperature. The result: A poor night’s sleep no matter how many hours you were in bed. The solution: Separate blankets or quilts chosen so you each can be supremely comfortable and get great sleep.

The bottom line: Unless you already are springing out of bed most mornings raring to seize the day, try spending a little more time in bed and improve your sleep habits by paying attention to what Dr. Gartenberg calls the “big three”— sound, light and temperature.

Note: If you’re being treated for insomnia, experts may recommend spending less—not more—time in bed, an approach called sleep restriction.

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