You lie in bed tossing and turning for hours but can’t get to sleep even though you’re exhausted. You’re lethargic all day but then stay wide awake at night. Friends and family call you the night owl even though you desperately wish to turn into an early bird. On top of that, your sleeplessness makes you anxious, worsening your “tired-but-wired” mind, and holds you back even more from those elusive zzzs.
If this sounds like you, don’t worry — there’s light at the end of the tunnel. Ahead, we explain why you can’t sleep even though you’re tired. From poor sleep hygiene and circadian misalignment to medical conditions like insomnia, you’ll learn how to remove these obstacles and get your energy back again.
To figure out why you might have trouble dozing off at night, it helps to understand how sleep “works”. We’ll use the Two Laws of Sleep — sleep debt and circadian rhythm — to explain it. The Two Laws are based on the two-process model of sleep regulation, the dominant scientific theory explaining the timing, duration, and structure of sleep that was first established by sleep scientist Alexander Borbély in the 1980s.
Sleep debt refers to the amount of sleep you’ve missed in the past 14 days relative to your sleep need (the genetically determined amount of sleep your body needs – not everyone needs eight hours). Sleep debt is a function of sleep homeostasis, a process in which sleep pressure builds up during the daytime and depletes at night when you sleep .
You can picture the sleep homeostat as a seesaw that always wants to be level. Here’s how:
Unfortunately, when you don’t get enough sleep, leftover adenosine means you’re groggier in the morning and sleepier during the daytime — common side effects of accrued sleep debt in the short term. If that sleep debt accumulates over time and isn't repaid, acute sleep deprivation becomes chronic. Consequently, your overall well-being deteriorates as you face an increased risk of health issues like heart disease, obesity, Type 2 diabetes, and even cancer.
RISE users on iOS 1.202 and above can click:
So far, you’ve learned how sleep pressure works in getting you to sleep at night and the consequences of sleep deprivation. But things aren’t as simple as that — remember, there’s a second part of the story we’ve yet to explore.
For one thing, if sleep pressure keeps rising from wake time to bedtime, why do we not succumb to sleep during the day (or in the case of napping, can sleep easily at some times and not at others)? For another, if sleep pressure evaporates with sleep, why do we only wake up when the alarm clock goes off and not (hopefully) before that, say, at 3 a.m.?
The answer to these questions lies in your circadian rhythm (the internal body clock), which helps regulate the timing and consolidation of both sleep and wakefulness.
Light, especially natural, bright light, is the greatest time-giving cue for your circadian rhythm. When you wake up, your eyes receive light that kick-starts a series of interrelated processes throughout the body: the master clock in your brain releases circadian alerting signals, which promote wakefulness to counter the now rising sleep pressure. At the same time, the body steps up its production of cortisol, norepinephrine, and serotonin to help you feel more awake and alert. The internal body clocks also govern your core body temperature (CBT). From 4 a.m. onward, CBT gradually rises to prime you for wakefulness.
Circadian-alerting signals rise steadily throughout the day, with a temporary drop in the early to late afternoon. This lull, combined with growing sleep pressure, is why you feel less energetic and more lethargic post-lunch, otherwise known as the “Afternoon Dip” in the RISE app.
Past your energy dip and nearing the evening, the circadian-alerting signals are in full force to counter sleep pressure that’s now at its peak. Your CBT also climaxes at around 6 p.m. to keep you awake and give you what feels like a second wind (fun fact: most world records are broken at this time). This is the second of your two energy peaks in the RISE app. Going to bed within this period is, under normal conditions, next to impossible.
In an ideal world, your internal body clock is in sync with the external light-dark cycle. So, when dusk falls and darkness settles in, the circadian alerting signals slowly disappear. Your CBT also declines to initiate sleep.
Meanwhile, your body starts to produce melatonin (a sleep-promoting hormone) 2-3 hours before you sleep in a process initiated by the so-called dim light melatonin onset (DLMO). DLMO marks the start of your Melatonin Window in RISE when the rate of melatonin production peaks. Per a 2012 article in the Psychiatric Times, the circadian rhythm for sleep propensity (readiness to fall asleep and stay asleep) intensifies when melatonin steps up its production. This, coupled with sleep pressure at its zenith, is what allows you to fall asleep at bedtime.
During the night, the CBT drops, until it hits its lowest at 4 a.m. To keep you asleep till morning (or whenever your alarm clock rings), sleep scientist Derk-Jan Dijk and colleagues found that the circadian rhythm for sleep propensity “peaks at or shortly after.” They also found that wakefulness only surges 4-8 hours after the trough of the CBT. This is why your nighttime sleep patterns aren’t in fits and starts but mostly continuous from nighttime till morning (barring middle-of-the-night awakenings).
As you can see, when sleep homeostasis and the internal clock are in sync, their well-timed push-pull dynamic keeps you awake for the most part during the day and helps you fall asleep and stay asleep at night. Any disturbances to the carefully orchestrated ecosystem — due to poor sleep hygiene, circadian misalignment, certain health conditions, or a mix of all three — are likely why you can’t sleep even though you’re tired (see next section).
Although it can be challenging to identify the exact cause(s), the inability to sleep even though you’re tired is usually due to poor sleep hygiene, circadian misalignment, certain health conditions, or a mix of all three.
Missing out on a good night’s sleep (or several) doesn’t necessarily mean your sleep health is in jeopardy. Just like how we all have bad days, sleep issues can pop up from time to time, whether it’s because you have a heavier workload lately or you’re caring for a sick child.
While temporary sleep problems are certainly challenging, it’s important to take a longer-term view of your sleep health while inspecting your daily sleep hygiene practices. It helps that acute sleep debt is measured over the past two weeks rather than from last night alone.
That being said, a chronic lack of sleep is cause for concern. Sleep debt and its debilitating effects mount quickly. It’s easy to move from acute implications like lower energy and poorer mood the next day to chronic consequences like an increased risk of metabolic health issues.
If you’ve had trouble sleeping well for some time now, take a look at the following possible causes to see which one(s) resonate with you most.
Sleep hygiene refers to behaviors that help keep the sleep drive and internal body clock in harmony. That way, you feel sleepy at the right time, stay asleep throughout the night, and feel awake and energetic throughout the day (save for the mid-afternoon dip).
While it’s easy to be confused by the term ‘sleep hygiene', these behaviors don’t only relate to sleep itself, like perfecting your sleep environment. Many healthy sleep habits actually take place during the day. Pivotally, most of these behaviors concern not just what to do, but when to do them. Carrying out these sleep-promoting behaviors sets you up for sufficient healthy, naturalistic sleep at the right time. Conversely, if you don’t carry out these sleep-promoting behaviors, or perform them at the wrong time, not being able to sleep when you’re tired becomes an unfortunate reality.
Some examples of poor sleep hygiene include:
Of course, the full spectrum of unhealthy sleep habits goes beyond the above instances. What’s more, these behaviors not only make it hard to fall asleep, but they can also make it difficult to stay asleep and fall back asleep if you woke up during the night. On top of that, you may also find it challenging to nap during the day, even if the nap is timed correctly to your afternoon circadian energy dip.
To tackle sleep-detracting behaviors, use the 20+ science-backed sleep habits in the RISE app.
RISE users on iOS 1.202 and above can click here to set up their personalized habits.
You’ll also want to check out The Rise Science Guide to Improving Your Sleep to perfect your sleep hygiene.
An out-of-tune body clock can make it challenging to sleep even when you’re tired.
The most relevant modern-day manifestations of circadian misalignment include:
Triggers for circadian misalignment can usually be traced to poor sleep hygiene. A classic example would be late-night light exposure from our phones in a bout of sleep procrastination that causes us to miss our Melatonin Window.
Circadian misalignment could also be due to life obligations that are out of sync with our biological preferences for when we want to be awake and asleep. For example, the aforementioned night shift workers or night owl chronotypes living in an early-bird world.
To complicate matters, poor sleep hygiene can also be compounded by life obligations to throw your body clock off course. To illustrate, a night shift worker may drink coffee to stay awake during their shift and have trouble sleeping once they get off work. In such cases, you can’t sleep even though you’re definitely tired from working all night.
RISE’s in-app habits can help you beat circadian misalignment for better sleep. In particular, try the “Blue Light Control,” “Evening Routine,” and “Melatonin Window” habits for well-timed light exposure, a relaxing wind-down routine, and learn the best time to go to bed, respectively.
RISE users on iOS 1.202 and above can click here to set up their personalized habits.
The International Classification of Sleep Disorders defines insomnia as “difficulty in either initiating sleep, maintaining sleep continuity, or poor sleep quality” (even though there’s no scientific consensus on what quality sleep means).
On a societal level, this sleep disorder plagues one-third of the general public. You may have acute insomnia (lasting about three months) or chronic insomnia (sleep problems occurring at least thrice a week in the last three months).
Many triggers exist for insomnia, from post-surgical pain to anxiety and stress over job loss. Arthur Spielman (a pioneer in the field of sleep science who helped create the non-pharmacological method for tackling insomnia) and his colleagues came up with the 3P model to explain how chronic insomnia comes about:
Improving your sleep hygiene is usually recommended. Sleep experts also favor cognitive behavioral therapy for insomnia (CBT-I) over temporary quick fixes like sleeping pills, as sleep medicine comes with unwanted side effects.
Your sleep specialist trained in CBT-I may walk you through protocols like sleep restriction, stimulus control (sleep reset), and cognitive techniques to reframe your fears regarding sleep deprivation.
Delayed sleep phase syndrome (DSPS) is a circadian disorder in which your biological clock significantly lags behind the societal clock.
For instance, you only feel sleepy at 2 a.m. when a conventional bedtime is around 10 p.m. Unsurprisingly, you have difficulty falling asleep if you go to bed at this hour. On your Energy Schedule in RISE, you may even see that this period is your last energy peak of the day, making sleep near physiologically impossible. To worsen matters, most people with DSPS rack up sleep debt that intensifies daytime sleepiness.
The good news is there are things you can do to shift your body clock forward and minimize sleep debt, mainly in the form of good sleep hygiene, such as:
If you still feel DSPS significantly affects your lifestyle after trying these tips, it’s worth speaking to a sleep specialist about your condition.
Besides sleep and circadian disorders, other medical conditions make dozing off challenging even though you’re tired:
If you suspect any of the above health conditions, make an appointment with a licensed healthcare provider to get the treatment you need and meet your sleep need.
Not being able to sleep even though you’re tired means you aren’t meeting your sleep need and racking up sleep debt. There’s also a high chance of circadian misalignment that’s challenging your sleep and your energy. All of these point to the fact that you aren’t feeling and functioning at your best.
Determine why you can’t get the rest you need and work toward the right solution. Depending on whether the root cause is medical or non-medical, you may need to consult a healthcare professional.
With that said, healthy sleep hygiene paired with your circadian rhythm is a critical first step in fixing your sleep problems. That’s where RISE can help. It helps you cultivate 20+ science-backed sleep habits so you can sleep at night when you’re tired. Download the RISE app today for better sleep for better days.
If you’re too tired but can’t sleep, it could be that you’re too keyed up to doze off. In this case, try relaxation techniques (like the ones in the RISE app) to calm down, relax, and put yourself in the right frame of mind for sleep. There could also be other possible causes, such as poor sleep hygiene, circadian misalignment, insomnia, or an underlying medical condition, that come with their own set of solutions.
If you’re tired all day and then wide awake at night, it’s usually because your body clock has gone awry. Try resetting your circadian rhythm, while practicing healthy sleep-promoting habits, as poor sleep hygiene is the other common reason why you can’t sleep at night.
Being tired but can’t sleep often leads to anxiety as you lie awake in bed at night. Unfortunately, anxiety and sleep loss feed into each other, creating a vicious cycle.
If you’re having trouble sleeping lately, it’s time to inspect your sleep hygiene. Our step-by-step Sleep Guide is a helpful resource. It could also be due to circadian misalignment as you struggle with social jetlag, travel jet lag, or shift work disorder. If you’ve ruled out both of these, an underlying health issue may be at play, so it’s recommended to consult a licensed healthcare professional.
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