Ever awaken after eight hours’ sleep feeling dead tired as though you’ve slept only four hours, but within 10 minutes of being up, your entire body is piping awake?

What the devil is going on here?

“Do I have sleep apnea?” You might wonder.

“Aren’t eight hours of sleep supposed to make me feel refreshed when I wake up?”

First off, don’t be mislead by all those TV commercials you’ve seen over the years in which sunlight from a window awakens someone and immediately they spring into a seated position in bed, throw out their arms to stretch, eyes wide open and face glowing.

Really, who wakes up this way?

And how many times have you seen TV shows in which someone wakes up in the morning yet appears as though they’ve been up and about for hours and just slid into bed momentarily?

But then again, maybe you’ve read in medical literature that after eight hours of sleep, a person should feel very well-rested and ready to spring out of bed – rather than feeling as though only four hours have passed and that they need yet another four hours!

“This effect is called ‘sleep inertia’ and, to a certain degree, is normal,” says Joseph Krainin, MD, board certified in sleep medicine and neurology and founder of the online sleep apnea clinic Singular Sleep.

“It is exacerbated if we wake up in a deeper stage of sleep instead of a lighter stage like N1 or REM, where our brain is already active and ready to tackle the day.”

• N1 – lightest stage of non-REM sleep.
• REM – rapid eye movement, during which we dream.

Feeling Alert Minutes After vs. Dragging for Hours

Within minutes of being up and about, following sleep inertia, a normal healthy person will feel as though they DID have eight fully recharging hours of sleep.

Despite feeling dead tired after shutting off the alarm, and despite having difficulty just sitting up in bed feeling like they just want to plop back down and slumber for another two or three hours, they are feeling perfectly fine by the time they’re in the bathroom preparing for the day – or whatever it is they routinely do in the first 10 minutes of being out of bed.

Sleep inertia doesn’t affect people as much, if at all, when they’re on vacation.

People will drag themselves out of bed after eight hours of sleep on a Monday morning to go to work and feel like sh–.

But only five hours after bedtime at 5 am on the first morning of their ski vacation…they spontaneously awaken – and, feeling too energized to sleep another few hours, they literally hop out of bed and feel as though they’ve been up for hours.

There’s a psychological component to some cases of sleep inertia.

Really, think about it. Who needs to drag themselves out of bed, feeling dead tired, on the first morning of their vacation in Disneyland, Vegas, Tahiti or a much-anticipated vacation golfing, sailing, cave-exploring or what-have-you?

Depression is also a contributing factor. Depression induces a feeling of needing more sleep and not wanting to get up and face the day.

Having to go to an unpleasant workplace can fuel a pre-existing depression.

These feelings magically disappear when one must get up early to go on a planned all-day trek in the mountains or to a beloved family member’s wedding.

Don’t Panic

Do not let feeling dead tired after eight hours of sleep convince you that you’re sick if you’re able to snap out of it within minutes after being out of bed and very productively tackle a busy day – and this scenario of productivity repeats itself over and over:

• This includes feeling wide awake throughout the day and evening, and never being tempted to nap.

• You never fall asleep watching TV or reading.

• You’re alert during all of your computer work.

• You’re wide awake driving.

• You kill it at the gym.

• After that you still have energy to play with the dog and kids.

• Come 11 pm you’re still wide awake.

• Okay, so you feel like sh—next morning, but you know that just being on your feet for five minutes will cure that.

Few people really do feel like springing out of bed after eight hours when they are faced with yet another (sometimes dreadful) day at the office.

This is not a sign of ill health, especially when there are sick-as-dog people who actually feel quite alert the moment their eyes pop open after only six hours of sleep.

In 2013 Dr. Krainin was elected a Fellow of the American Academy of Sleep Medicine, an honor reserved for sleep doctors who’ve made significant contributions to the field in education, research and service.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.