We’ve all experienced waking up unexpectedly in the middle of the night, or fumbling to turn off the alarm when we don’t feel fully rested. But some folks, including first responders and new parents, have to rise and shine without much — if any — warning. And they do this over and over and over again, often with lives depending on it.
Jolting your system awake in emergency situations or rolling out of bed to care for another person at 3 a.m. can confuse both your body and mind. When you awaken abruptly, it’s normal to be groggy — feeling alert is no easy feat. That’s because of a phenomenon called sleep inertia. Sleep inertia is the temporary disorientation and impaired cognition you experience when transitioning suddenly from sleep to an awakened state.
We talked to sleep experts, emergency room staff, and law enforcement officers about the science of sleep inertia and how to feel ready at a moment’s notice.
What is sleep inertia?
Sleep inertia was first discussed in sleep science literature in the late 1930s. It’s a term used to describe the paradox of feeling sleepy when you first awaken, despite a good night’s rest. Scientists theorize that the initial grogginess most of us experience when our alarms go off is intended to keep us from completely waking up between sleep cycles. We typically go through multiple cycles each night (each lasting approximately 90 to 110 minutes), helping us move in and out of deeper restorative states that allow our bodies and minds to recoup from daily wear and tear.
Sleep inertia may also help you transition more slowly from rapid eye movement (REM) sleep to wakefulness. A slower transition might decrease your chance of experiencing hypnopompic hallucinations, like sleep paralysis demons. Yes, those are a thing.
This sleepy state can also help you easily drift off again if you do happen to wake up in the middle of a sleep cycle, perhaps to use the bathroom.
You may feel groggy when the alarm goes off (or you wake up to pee) because as you sleep, your body clears adenosine, a sleep-promoting neurotransmitter that accumulates before bedtime, and if you wake up too early, you’re still experiencing the effects of this neurotransmitter, explains neurologist and Sleep.com advisor Dr. Chris Winter.
Sleep inertia was designed to help us, but it can certainly be a pain point when we need to wake up alert and on top of our game.
Waking up for emergencies
While most of us have some time to clear grogginess after we roll out of bed, first responders have to jump right into action — often dealing with demanding situations within minutes.
Take Jameson Gartner, for example, who, as a member of a special weapons and tactics (SWAT) team, had to wake up at all hours and be ready for a high-stakes job.
“When I was on SWAT, we were on call 24/7,” says Gartner, who spent 18 years in law enforcement in Colorado. “I had about five minutes to be out the door. It could be very difficult to be alert, but you didn’t have a choice. SWAT doesn’t have time to slow things down.”
Medical professionals on call grapple with the challenges of sleep inertia, too. “In general, I have about 30 to 60 minutes to get from my bed to the operating room (OR) and get started,” says Dr. Jordan Frey, a surgeon specializing in blood vessel microsurgery. He can be called into the OR for emergency surgery at any time of the night or day.
“First responders have to manage constant disruption, facing life or death situations that depend on their ability to stay rested and sharp,” adds Winter. “They have to be at their physical and mental best at a moment’s notice.”
Waking up abruptly throughout the night can come with real risks for your health and cognition. Research shows a pattern of interrupted sleep may impair your thinking and memory more than a whole 24 hours of sleep deprivation.
How to wake up feeling alert
So how do you wake up at a moment’s notice and perform surgery, tend to a child, or rush to put out a fire? Here are some tips from people who do it regularly.
- Drink water. “You’re always dehydrated when you wake up,” says Frey. “Drinking water helps my system to get back in gear more quickly.” Keep water by your bedside so you can grab it when you wake up. Plus, keep an emergency bottle or two in your car.
- Splash cold water on your face. This can arouse your sympathetic nervous system — that’s your fight-or-flight response — and increase wake-promoting neurotransmitters, such as norepinephrine, Winter explains. You want to resist the urge to be warm and cozy. Remaining warm could keep you feeling groggy by continuing to activate your parasympathetic nervous system — or your rest-and-digest response. If cold water doesn’t do the trick, keep the windows rolled down on the drive, or crank the air conditioning.
- Move around. Exercise, Winter says, can also activate the sympathetic nervous system quickly. Jog in place for a moment or do a few jumping jacks to get your heart pumping a little faster.
- Brush your teeth. By going through the motions of a normal morning routine, you condition yourself to feel more awake, like it is the actual morning, says Frey. Plus, the tingling sensation of mint can awaken your senses.
- Drink coffee. “Caffeine temporarily blocks the effects of adenosine,” Winter says, “so I’m all for it if needed.” Remember, adenosine is a sleep-promoting neurotransmitter that might not be fully cleared from your system if you wake up in the middle of a sleep cycle. Keep some cold brew in the fridge so you can grab and go without having to mess with a machine or press. That said, skip the coffee if it’s not your thing. “I avoid caffeine,” Frey says, “because I recognized in college that it had an adverse effect on me. It didn't just wake me up; it made me more anxious and overly jittery.”
- Eat a snack. A snack provides the quick fuel you need to get going. “I always carried water and food in my gear,” Gartner says. In a rush, you might not have time to put much in your stomach, and that’s a good thing, according to Winter. Heavy foods could make you feel sluggish. Stick to something light and quick.
- Get some light. According to research, a little light may help you feel more alert by suppressing melatonin release. Rather than sleeping in the dark, Theresa Weinhold, a nurse practitioner, leaves the lights on while getting some shut-eye during an overnight shift. That way, when she has to wake up to send information from her phone, or jump into action, it takes less time to adjust. Gartner says he would power up his laptop in the car to offer a little glow in the hopes of feeling more awake.
- Engage your mind. “I force my brain to think through the steps that I am going to take once I’m at the hospital and in the OR,” Frey says. “Being active with my thoughts helps jolt me awake and into the right mindset.” Gartner used similar tactics. He says he would interact with the people around him to increase alertness.
How to recover after waking up abruptly
Sleep inertia, while potentially helpful for most of us as we sync with sleep cycles, can have serious repercussions for folks who have to wake up and tend to trauma.
Jeff Burns, a surgical assistant in Texas, says he used to not be able to sleep while on call, because he was always worried about the effects of sleep inertia if he got called in. But over time, he realized he had to rest. He got used to the temporary tiredness upon waking. “When they call,” he says, “I somehow snap out of it quick and I’m awake. Mainly because I’m annoyed I have to go in!”
Once you’ve made it beyond the initial stage of grogginess and have started to work or tend to your loved one — or whatever it is that requires you to be alert — you might start to feel a bit bleary-eyed again, as your truncated sleep session catches up with you. That’s Frey’s experience. But he has a solution.
“I try to take a short nap,” he says. “Anything more puts me into sleep inertia again and I will wake up groggy.” How short? Research suggests 10 minutes. Longer snoozes may put you in more slow-wave sleep (aka deep sleep).
But Gartner says he did best when just powering through. “I tried to maintain my schedule,” he explains, “because if I slept for two hours, then would I have a hard time falling asleep that night.”
Winter recommends staying busy throughout the day and engaging in some movement to generate some energy. Keep avoiding heavy foods, though he says spicy items might make some people feel more awake. Keep hydrated and be sure to get a good night’s rest when you can.
Several medical professionals say their call alarm is all they need to shake themselves awake. So if you need to be up unexpectedly on a regular basis, train yourself with a dedicated sound and a set of steps that automatically perk you up. “Your mind is so amazing,” says Burns. “Once you wire your brain to react to being called in, it just adjusts and the adrenaline kicks in.”
In addition to training your body and mind for disruption, Winter says self-care if critical. “A resting period here, or an exercise period there, can make a huge difference,” he says. “It makes a really big difference in your capacity to take care of others, but it also helps you maximize and protect your own health.”
