Why Can’t I Sleep Even Though I’m Tired?

When you’re exhausted all day long, the one thing that should be easy is falling asleep at night. But sometimes, even if you’re yawning constantly and counting down the minutes to bedtime, dozing off is difficult.

The dreaded phenomenon of feeling “tired but wired” is a hallmark feature of clinical insomnia. But it’s also something that many people who don’t have a diagnosed sleep disorder struggle with occasionally. Multiple factors might explain why sleepiness and sleeplessness coexist, and some are at least partially within your control. One of your daily habits, or your mentality toward sleep, for example, might be getting in the way of good shuteye.

Here we’ll explore why this happens, and reveal some of the top reasons that you can’t fall asleep even though you can barely stay awake.    

What controls your ability to fall asleep easily?

It should take between 10 to 20 minutes to fall asleep once you’re in bed with the lights off. Lying awake in bed for 45 minutes or more is considered too long, and passing out immediately can be a sign of sleep deprivation. But occasionally taking a while to fall asleep is normal, as is falling asleep quickly sometimes. There’s no reason to worry unless a pattern develops.  

Whether or not you nod off soon after your head hits the pillow depends primarily on two complementary processes, explains Aric Prather, PhD, a psychologist who runs a stress lab at University of California, San Francisco and specializes in treating insomnia with cognitive behavioral therapy.

The first is homeostatic sleep drive. This is what makes you feel drowsy and provides the “pressure” to go to sleep. It occurs due to a sleepiness-inducing substance called adenosine, which builds up in your brain over the course of your waking hours, and then gradually returns to zero while you’re sleeping. Prather likens this to a balloon that fills up throughout the day. Once it’s completely inflated, it’s time to drain out the air. A night of sleep drains out your sleepiness, which then starts reinflating in the morning.

The second factor is the circadian system. Your sleep-and-wake cycle is one of numerous circadian processes, which are governed by a master clock in your brain and run on a 24-hour-schedule. Several environmental factors can shift the timing of when your body falls asleep, but sunlight is the strongest cue. That’s because light exposure suppresses melatonin, a key hormone in inducing tiredness, while darkness triggers its release. So, melatonin levels are low during the day and higher at night.

If you go to bed and wake up at consistent times, and you sleep at night, then you’re setting yourself up to feel tired around your desired bedtime. By that point, your homeostatic sleep drive is high, and your melatonin levels are elevated, so both processes sync up to support well-timed drowsiness.

Some everyday habits can throw your sleep systems off

If you can’t fall asleep at bedtime, it’s likely that something has set these core processes off kilter. Some possibilities to consider:

• An erratic schedule. If you keep irregular or unconventional hours, you’re more vulnerable to circadian dysregulation. A night-shift worker, for example, might feel exhausted by 10am, because they’ve been awake for a long time, but still struggle to fall asleep because it’s light out and their melatonin levels are low. Similarly, changing time zones throws off your body clock. You’ve probably dealt with jet lag at some point. Frequent long-distance travel can wreak havoc on internal sleep-wake cues, because your body keeps encountering new cycles of light and darkness.
  A melatonin supplement can help if you need to reset your sleep schedule, or adapt to time changes more rapidly than your body can handle on its own. Melatonin has become a popular sleep aid, but it’s not technically a sedative. It’s most effective for addressing circadian misalignment. Dosages sold in stores vary a lot, and there’s some evidence that lower doses work as well as higher ones. It’s a good idea to talk to a doctor before taking it.

• Caffeine sensitivity. Caffeine wakes you up by blocking receptors in the brain for adenosine, the substance that controls your sleep drive. The half-life of caffeine, meaning how long it stays in your system and has stimulating effects, varies considerably from one person to the next, says Anthony Reffi, PhD, a clinical psychologist and assistant scientist at the Trauma Recovery Center and Sleep Research Center at Henry Ford Health. It can last up to 12 hours for some people, whereas others metabolize caffeine in four to five hours. Because of this variability, recommendations for when to stop drinking coffee to prevent sleep interference tend to be vague. But, if you want to be safe, avoid caffeine within 8 to 10 hours of bedtime. If you find that 10 hours isn’t enough, Reffi says, “you may just be more sensitive to the drug and might try consuming it even earlier or in a smaller dose.”

• Too much time on electronic devices, especially in the evening. Your phone, laptop, and TV all emit blue light, which research suggests can inhibit melatonin production for some people, Prather says. (But direct sunlight is a lot more powerful.) Staring at a screen before bed might weaken circadian cues, making it harder to fall asleep.
  How much screen time is too much? Well, one study found a link between poor sleep and screen use exceeding six hours a day. But, for the sake of your sleep, what matters most is avoiding screens close to bedtime, not curbing your overall daily screen time. Research supports ditching devices at least one hour before bed. 

• Using social media at night. In addition to blue light, there’s another downside to scrolling your social feeds before bed. Social media is designed to activate your brain’s reward network, which is cognitively arousing and can counteract feelings of sleepiness. So even if you filter blue light from screens, your phone might still have a stimulating effect. The same is true for video games and exciting sports games.

Stress can also override your ability to fall asleep

When you’re stressed, something called the stress response can override your homeostatic sleep drive and circadian system, keeping you awake even when you’re tired.

“Stress triggers the sympathetic nervous system to become very active,” says Reffi, “whether this threat is merely perceived (e.g., work stress) or real (e.g., trauma exposure).” This is called a stress response: Your sympathetic nervous system releases hormones, which cause neurophysiological changes that prepare you to run away, hide or fight. These changes include a faster heartbeat, heavy breathing and sweating, increased mental alertness, and racing thoughts.

Stress response is an adaptive mechanism — it allows you to make quick decisions and movements, which is extremely helpful when you’re actually in danger. But it’s the last thing you want when you climb into bed after a long day. 

“We like to describe the stress response as a mask that hides sleepiness,” says Reffi. “In other words, it is not as though the person lacks sufficient drive for sleep, but rather, it’s that their sleepiness is obscured by this hyperarousal.”                  

There’s a lot of individual variation in how easily stress gets in the way of daily functioning, and  

“sleep reactivity” describes the degree to which being stressed affects your ability to sleep. People who are highly sleep reactive sleep terribly when their stress levels soar, while those with low sleep reactivity can feel overwhelmed by stress and still get a solid night’s rest. 

“People can often identify those in their lives with low or high sleep reactivity,” says Reffi, whose lab has done extensive work on the topic. “For example, a lot of my female patients with insomnia would complain of their husbands’ ability to sleep no matter what was going on, whereas they would find themselves struggling to sleep because of things like knowing they had to get up early the next day.”

Reffi says that experts still don’t fully understand why some people have more sensitive sleep systems than others, but that there’s some evidence high sleep reactivity is linked to lower activity in the parasympathetic nervous system — the part that regulates “rest and digest” functions that calm us down. That means a highly reactive sleep system might indicate a lower ability to bring down arousal during sleep.

After a while, the thought of poor sleep can create even more stress

If you aren’t sleeping well — because of stress or for any other reason — you might start to worry about not sleeping. This is a common feedback loop, and the fretting often happens when you’re in bed, explains Prather.

“You’re tossing and turning and worrying how you’re going to get through tomorrow, and it begins to create a conditioned arousal,” says Prather. “You’re awake but you’re in bed, and the association can lead to that tired-but-aroused feeling.”

Putting pressure on yourself to get more sleep is counterproductive. “Sleep feels so unpredictable and broken, so people think throughout the day about what they can do to get more sleep, like going to bed early so they can catch up on the sleep they should be getting. It makes so much sense in the moment, but actually undermines how sleep works,” says Prather. “That’s one of the challenges — all of the things that people try to do make them more tired and wired.”

If stress is keeping you up at night, there are some simple strategies that might help you power down:

• Write a pre-sleep to-do list. A 2018 study evaluated how writing at bedtime affects sleep latency (the amount of time it takes to fall asleep). Researchers compared two different exercises: 1) making a list of activities completed within the past few days, and 2) making a list of things to get done over the next few days. Across the board, participants who wrote to-do lists fell asleep faster than those who jotted down what they’d accomplished. And the more specific participants were in their to-do items, the quicker they dozed off. This might be because you’re developing small plans for how and when each item on the list will be carried out, says lead study author Michael K. Scullin, PhD, associate professor of psychology and neuroscience, and a sleep medicine specialist at Baylor University.  .

• Journal about your feelings. Writing exercises, in general, can be beneficial for anxiety and worrying, says Scullin. “When we write something down, we “offload” it, meaning that we are less likely to spontaneously be thinking about it than if we hadn’t written it down.”

• Practice slow breathing. This might help combat stress-induced alertness because it increases activity in the parasympathetic nervous system, and also because it can lead to increased melatonin production. Studies have shown that people with insomnia fall asleep faster (and report better quality sleep) when they practice slow-breathing techniques at bedtime.

• Don’t think about sleep. Try to accept that it’s OK if you don’t sleep well one night. It happens to everyone. The best way to course-correct is to shake it off and move forward.

• Develop a nighttime ritual. In order to hit that sweet spot of falling asleep within 10 to 20 minutes, you need to give your body a heads up that bedtime is coming. Nighttime rituals, such as dimming the lights an hour before bed and doing a calming activity like reading, listening to soothing audio, or connecting with a loved one, can function as cues to your body that it’s time to transition into sleep mode. “Sleep is universal but also personal, so there are things that get people relaxed that are unique to them but work,” says Prather. “You need to be able to let go, and the things we do in our lives that allow for that can make all the difference.”

The Tone Take: You can reclaim that sleepy feeling

If all of this advice seems overwhelming, don’t worry. You can try implementing one tip or rule at a time, and figure out what works for you. Resetting a sleep schedule can take time, and so can forming a new habit. The best thing you can do is commit to making small changes and accept that progress is gradual.