It's one thing to yawn at your desk in the middle of the afternoon, and something else entirely to experience actual symptoms of sleep deprivation. These are often more intense. And yet, it's easy to confuse them with a bout of drowsiness, or a simple desire to go to bed.
"Sleep deprivation results in sleepiness, but you don’t have to be sleep deprived to be sleepy," Dr. Nate Watson, a sleep scientist from SleepScore Labs, tells Bustle. "Sleepiness is normal during our mid-afternoon dip in circadian alertness (also the time when the coffee line is the longest) or in the evening after dark." And it can also come about due to things like boredom, caffeine withdrawal, or as a side effect of certain medications.
If you have sleep deprivation, though, there will likely be a different set of symptoms, all stemming from a lack of sleep. You'll still feel tired and yawn at your desk. But you might also notice experience things like a lack of coordination, micro-sleeps, and even a sense that you're "wired" or stressed.
To prevent sleep deprivation, you'll want to get seven or more hours of sleep every night, Watson says. Also, keep in mind, there is no substitute for sleep, he says. Even if you can get by on a few cups of a coffee and a quick nap, your body needs those seven hours in order to stay well.
So how do you know if you're more than just tired? Or simply experiencing a little fatigue? Here are the ways to tell the difference between sleepiness and sleep deprivation, according to experts.
1. You Have "Micro-Sleeps"
Typical afternoon sleepiness might not cause you to actually fall asleep. But sleep deprivation can, and in some pretty weird and scary ways. "Sleep deprivation can result in micro-sleeps, brief seconds-long periods of sleep where awareness is diminished, and memory is affected," Watson says.
The trouble is, you might not even know it's happening. "In fact, the more sleep deprived and sleepy a person is," Watson says, "the less well they are able to assess their resulting level of impairment."
It's no surprise micro-sleeps can be incredibly dangerous, especially if they occur while you're driving. And that's why it's so important to get enough rest each night, so that you aren't putting yourself and others at risk.
2. You Feel Weirdly Alert
"Though sleepiness and sleep deprivation sound like the same thing, they can have little to do with each other," Rose MacDowell, sleep expert and chief research officer at Sleepopolis, tells Bustle. "You can feel sleepy even on sufficient sleep, and alert after an all-nighter."
If you didn't get much sleep, and yet feel wired and awake, take note. "Sleep deprivation can result in a feeling of manic energy instead of sleepiness," MacDowell says.
And that's because it activates stress hormones like adrenaline and cortisol, leaving you jittery and alert. "If you didn’t sleep much (or at all) the night before but have more energy than usual," she says, "you’re suffering from sleep deprivation instead of sleepiness."
3. You're Taking A Medication
Certain medications can cause fatigue as a side effect, so if you can't keep your eyes open or feel more sleepy than usual, this may be why.
"Almost any over-the-counter or prescription drug can cause sleepiness," MacDowell says. "Common culprits include medications for allergies, motion sickness, heart conditions, depression, and muscle spasms."
If it's bothering you, let your doctor know. They may be able to make an adjustment so you feel less sluggish during the day.
4. You're Bored
"Even a well-rested person can feel sleepy without sufficient physical or mental stimulation," MacDowell says, which is why, if your eyes are getting heavy in a long-winded meeting, or your feel yourself drifting off during a long commute on the train, you're probably just bored.
It can help to switch up your routine and shake things up, MacDowell says, or to look for more ways to be stimulated throughout the day. That can help shake off this form of sleepiness, by keeping you more engaged.
5. You're Getting Your Period
"Pregnancy, PMS, and perimenopause can cause sleepiness even if you’re sleeping enough every night," MacDowell says. "Progesterone, known as 'the relaxing hormone,' is mildly sedating and commonly results in daytime drowsiness," and it can spike during these times.
It can cause you to feel extra tired right before your period, for example, even if you're getting plenty of sleep. When that's the case, it's often best to slow down and get even more rest, until your period's over. You can also point it out to your doctor, and see if they have any advice.
6. You're More Accident Prone
If you drop things all the time, or trip over your own feet, consider how much sleep you're getting each night.
"If you get by on less sleep than you should, you may be experiencing the effects in less obvious ways," MacDowell asys. "Even if you don’t feel sleepy during the day, if you’re accident-prone, have difficulty concentrating, [or] feel irritable [...] you may be feeling the negative impacts of sleep deprivation."
This will be your cue to pay more attention to your sleep schedule, and find ways to get those seven hours. It can help to practice good sleep hygiene, which means going to bed and getting up at the same time every day, and making your bedroom is conducive to sleep.
7. You're Quitting Caffeine
Cutting back on caffeine can cause some pretty intense sleepiness, even if you're getting enough shuteye each night. And that's because "caffeine blocks receptors for adenosine, a neurotransmitter important in the sleep-wake cycle," MacDowell says. "Cutting down on caffeine unblocks adenosine receptors, temporarily increasing feelings of sleepiness while your body adjusts."
Sleepiness, while not always fun, isn't the biggest deal. You may feel a little sluggish in the afternoon, or a bit rundown. But if you're more than just tired, it's likely due to sleep deprivation. And the best way to remedy that is with some good old-fashioned sleep.