Why Can’t I Sleep? 31 Reasons to Watch Out For

From obvious causes like caffeine to little-known ones like ill-timed light exposure, here are 31 reasons why you can’t sleep.
Reviewed by
Jeff Kahn, M.S., Rise Science Co-Founder
Our Editorial Standards
We bring sleep research out of the lab and into your life. Every post begins with peer-reviewed studies — not third-party sources — to make sure we only share advice that can be defended to a room full of sleep scientists.
Learn more
Updated Regularly
We regularly update our articles to explain the latest research and shifts in scientific consensus in a simple and actionable way.
Woman lying in bed at night looking at cellphone unable to sleep because of ill-timed light exposure

Humans have achieved a lot in the post industrial age; we’ve traveled into space, made life-saving medical discoveries, and created the Internet, just to name a few. But for all our momentous achievements, we’ve also lost the art of sleeping well. 

The ironic thing is that we were once very good sleepers — around the time of hunter-gatherers, that is. Fast-forward to the dawn of electric light, we’ve invented myriad ways to interfere with getting the healthy naturalistic sleep we need to be our best. Most of us now struggle to reacquaint ourselves with what is actually an innate ability to sleep.

If you, like countless others, often lament about why you can’t sleep, this list is for you. From the most obvious causes like caffeine to the little-known ones like ill-timed light exposure, you’ll be sure to find the answers so that you can start sleeping well again.

Are You Sleeping Well?

RISE app photo showing how much sleep debt you have.
The RISE app shows your running sleep debt on your Sleep screen so you'll always know if you need to actively pay it down or not.

Not being able to sleep well typically means:

  • Excessive sleep latency, in which you have trouble falling asleep
  • Excessive sleep fragmentation, in which you wake up frequently during the night, and then possibly struggle to fall back asleep
  • Waking up earlier than you would like to

Disrupted sleep patterns make it hard to meet your biological sleep need (the genetically determined amount of sleep your body needs). Consequently, you accumulate sleep debt — the amount of sleep you’ve missed in the past 14 days relative to your sleep need.

That said, you may not have a sleep problem at all. It’s normal to expect some sleep latency and fragmentation. For instance, we usually take about 20 minutes to fall asleep — any faster than that is a sign of sleep deprivation. Also, it’s common to wake up in the middle of the night.

Your shorter-than-average sleep duration may also reflect a lower sleep need than the average of 8 hours and 10 minutes per night (plus or minus 44 minutes or so). That said, scientists admit any sleep need that’s six hours or less is incredibly rare.

On top of that, it’s not unusual to have a bad night here and there. Rather than let anxiety over sleeplessness contribute to yet more sleeplessness, take a long-term view of your sleep health. Look at how you’ve slept for the last few weeks rather than last night alone.

Why Can’t I Sleep? 31 Reasons to Watch Out For

1. Ill-Timed Light Exposure

RISE app screenshot showing you when to get and avoid blue light.
The "Blue Light Control" habit tells you when to get blue light and when to avoid it to help regulate your body clock.

There’s a good chance ill-timed light exposure plays a significant role in why you can’t sleep. It sends the wrong signals to your circadian rhythm (the internal clock) so that your body mistakes nighttime for day and vice versa.

Many people who think they have a sleep problem actually have a light problem. They most likely have too little natural light exposure after waking and during the day, and then too much artificial light exposure during the evening hours. In fact, even staying in a low-lit room (1-2% of the strength of daylight) at night can suppress melatonin synthesis by as much as 50%!

Even once you’ve gone to sleep, you aren’t completely safe from artificial light exposure, such as when you switch on the light to use the bathroom. Put on your blue-light blocking glasses when you use your phone flashlight to go to the bathroom instead of turning on the overhead lights. Wearing blue-light blocking glasses during your wind-down routine is helpful too. 

As mentioned, a common pitfall is when you receive too little natural light after you get out of bed in the morning. Research explains that sufficient light exposure during the day makes you sleepier in the evening, so you fall asleep more quickly and achieve more deep sleep. Try the “Blue Light Control” habit in the RISE app to leverage light exposure to your advantage.

2. It’s Too Noisy

Even if you think you’ve acclimated or it doesn’t bother you, a bedroom that’s too noisy — cue the snoring partner and loud traffic sounds — may be what’s stopping you from a good night’s rest. Our Sleep Guide teaches you how to soundproof your room for better sleep tonight. We also recommend adding the “Wear Ear Plugs” habit to your Energy Schedule in the RISE app.

3. It’s Too Hot

Your body’s core body temperature (CBT) naturally drops in preparation for sleep. Feeling hot (and not in a sexy way) is probably another big reason why you have trouble sleeping. The guilty parties could be your bedroom temperature, too-thick sleepwear, and even foam mattresses (which notoriously trap heat).

Once you eliminate these culprits, you’re likely to meet your sleep need more effortlessly. Our post on “The Best AC Temperature for Sleeping” can help you out further.

4. Late Workouts

Exercising too close to your bedtime also hikes up your CBT as well as elevates your cortisol levels (the stress or alertness hormone). The result is a delayed bedtime. But be advised, working out too little may increase your sleep latency and shorten your sleep schedule. You may also spend less fewer of your sleep cycles in deep sleep.

So, what’s the best solution? Add the “Earlier Workouts” habit to your Energy Schedule to help you sweat it out earlier in the day. You may also be interested in other do’s and don’ts in our tell-all guide to exercising before bed.

5. Pets in Bed

From restless rustling to middle-of-the-night potty breaks, snuggling up with your pet tops the list of common sleep disturbances among pet parents. If you want to avoid daytime sleepiness, it’s best to invest in a personal doggy bed for Fido.

6. Late Alcohol Consumption

RISE app screenshot reminding you when to avoid alcohol.
Add the "Avoid Late Alcohol" habit to your Energy Schedule to steer clear of its sleep-disrupting effects.

Did you know a single drink too close to your bedtime negatively impacts your sleep?

While alcohol initiates the zzz’s, it fragments your sleep and suppresses rapid-eye-movement (REM) sleep. The detoxification process also dehydrates your body, so you’re more likely to wake up from the resulting thirst than sleep through the night to meet your sleep need.

To avoid these sleep troubles, the RISE app tells you your cutoff time based on your unique chronobiology. Just add the “Avoid Late Alcohol” habit to your Energy Schedule.

7. Excessive Water Intake

While you won’t want to go to bed thirsty, it’s also unwise to drink too much water before you sleep. Doing so only guarantees you will wake up in the middle of the night to relieve yourself, making it harder to get enough sleep.

Our guide on drinking water before bed teaches you how to hydrate at the right times throughout the day.

8. Too Late in the Day Caffeine Consumption

Caffeine is a notorious sleep-detracting stimulant as its effects last for up to 10 hours. If you had your last cup at 4 p.m., it’s likely the reason why you’re still counting sheep at 2 a.m. that night.

To avoid this scenario, the “Limit Caffeine” habit in the RISE app tells you when to stop consuming caffeine based on your unique chronobiology. Bonus: Our post on “Energy without Caffeine” shows you why it’s more a possibility than a pipe dream.

9. Late Evening Meals

RISE app screenshot showing you when to have your last large meal for the day.
The "Avoid Late Meals" habit tells you when to cut off calorie consumption for better sleep tonight.

Eating too late doesn’t just incite the not-so-fun side effects of indigestion and acid reflux, along with increased blood sugar levels, cholesterol levels, and high blood pressure.

Food consumption also elevates the CBT as blood rushes to the gut (the core of the body) to help digest and absorb nutrients. This nullifies the slight drop in CBT to promote sleep.

Emerging research from Satchin Panda (author of The Circadian Code) shows that having your last bite of food (including “late-night snacks”) 2-4 hours before bed can “increase the arousal threshold” of sleep. In other words, you’ll enjoy more restful, deep sleep and be less likely to wake during the night from disturbances.

The “Avoid Late Meals” habit in the RISE app will tell you when to stop eating before bed. You may also wish to check out other related FAQs in our guide on “Sleeping After Eating.”

10. Pre-Bedtime Arousal

Whether it’s rushing for a work deadline, watching a thriller, or arguing with a spouse, pre-bedtime arousal is fodder for sleepless nights (unless we’re talking about physical intimacy). The elevated heart rate, adrenaline rush, tense muscles, and cortisol spike all work against your plans for healthy, restorative sleep.

For that reason, carve out time for an evening wind-down to put yourself in the right frame of mind for bed. The “Evening Routine” habit in the RISE app lets you customize a wind-down routine that works best for you.

11. Late-Night Stress and Anxiety

Being stressed out and anxious throws your body’s cortisol production off-kilter. Because cortisol is an alertness-promoting hormone, the last thing you need is a surplus of it right before bed. Cortisol excess not only prolongs sleep latency but also incites middle-of-the-night awakenings which come with their own layer of worry. This triggers a vicious cycle of more stress and anxiety at the expense of sleep.

Ironically, some people credit their anxiety to their sleep tracker as they unrealistically strive for the “perfect sleep score” (more on this later in no. 26). Sleep experts call this obsession orthosomnia (a type of sleep disorder).

To pull the plug on unwanted stress and anxiety clouding your sleep, learn how to calm anxiety at night.

12. Sleep Aids

Sleep aids may be beneficial in the short term for certain situations under the guidance of a medical practitioner. But relying on sleep aids over time will inevitably lead to an unhealthy dependence on them.

A large, well-designed study revealed that sleep aids, specifically Z drugs, reduced sleep latency by 22 minutes, but half of this effect is attributed to the placebo response. Given the unwanted side effects of sleep aids, and the specter of “rebound insomnia” after you stop taking them, the researchers advocate for therapeutic interventions like cognitive behavioral therapy for insomnia (CBT-I) over such medications.

You may also be intrigued to hear that your body is already equipped with the right tools to sleep well that don’t involve actual pills or supplements. Head over to our post on “The Best Natural Sleep Aids” to learn more.

13. Snoring

Snoring isn’t just a source of noise pollution for your bed partner. It can also indicate an underlying sleep-related breathing disorder, like obstructive sleep apnea (see next point). 

A 2015 review in the Journal of Sleep Medicine highlighted that snoring on its own is a “risk factor for poor sleep.” Simple tweaks like switching to a side-sleeping position may help.

14. Obstructive Sleep Apnea (OSA)

Obstructive sleep apnea affects your breathing patterns when you snooze. This leads to lower oxygen levels and poor sleep. Affected individuals usually experience excessive daytime sleepiness, a foggy brain, and irritability, amongst other symptoms.

Healthy lifestyle changes like regular exercise and weight management may help with mild cases of OSA. Your primary doctor may also recommend continuous positive airway pressure (CPAP) to manage your condition.

15. Parasomnias

According to ScienceDirect, parasomnias are “abnormal movements or behaviors that occur in sleep or during arousals from sleep.” Common ones include sleepwalking, sleep talking, and night terrors. During these arousal disorders, the affected individual abruptly awakens from deep sleep.

These sleep disruptions mean you’re unlikely to meet your sleep need and feel tired the next day. Aside from pharmacological and therapeutic treatments like antidepressants and scheduled wakings, good sleep hygiene can help tamp down the worst of parasomnias.

16. Insomnia

If you’re reading this list, you’re probably no stranger to insomnia.

Classified as the most common sleep disorder and characterized by difficulty falling asleep and sustaining sleep, insomnia plagues roughly one-third of the population in America. A newer form of insomnia called “COVID-somnia” has also emerged, as sleep disturbances reached new heights during the pandemic.

Before you down sleep supplements (remember their limited efficacy and side effects!), give CBT-I a shot instead. The American College of Physicians (ACP) advocates for CBT-I as the “first-line treatment for adults with chronic insomnia.”

17. Restless Legs Syndrome (RLS)

Restless legs syndrome is a brain disorder that features an uncontrollable urge to move the legs to relieve unpleasant sensations in the lower extremities. Unfortunately, these sensations intensify in the evening and nearer to bedtime, such that the condition leads to restless sleep.

A licensed healthcare professional may recommend lifestyle changes like foot massages, yoga, and medications based on your individual condition.

18. Depression

As if depression isn’t trying enough, this mental health condition also comes with its own baggage of sleep problems. New research explains that sleep disturbances and depression share a bidirectional relationship, in which insomnia is “an independent risk factor.” More data indicate that poor sleep worsens depression and anxiety in postpartum women, suggesting the need for better maternal sleep hygiene to curb this vicious cycle.

Interestingly, one study showed that pulling an all-nighter “improves depressive symptoms in 40-60% of treatments.” While this may seem like a better alternative to pharmacological options like antidepressants, sleep deprivation should only be used under the guidance of a licensed healthcare professional in managing depression.

Given that depression often co-exists with insomnia, a 2018 systematic review suggests CBT-I as a “promising treatment.” Improving insomnia may mitigate depression in affected individuals.

19. Living at Odds With Your Chronotype

If you find it difficult to fall asleep by your target bedtime, you may be living at odds with your chronotype. A classic example would be a night owl living in an early-bird world. Because your chronotype is largely genetically influenced, aligning your body clock to a sleep schedule that’s earlier or later than your natural inclination will be a continuous, active process.

20. Travel Jet Lag

Crossing time zones may satisfy the wanderlust but not your sleep schedule. Your circadian rhythm goes off-balance, exposing you to travel jet lag. As your body clock takes time to catch up to the new time zone, expect increased sleep latency and fragmentation, coupled with daytime grogginess. Learn more about travel jet lag symptoms and how long travel jet lag symptoms last here.

21. Social Jetlag

You don’t have to travel to experience jet lag. Case in point: Social jetlag, in which a mismatch between the social and biological clocks leads to an irregular sleep schedule and ensuing sleep deprivation, impacts roughly 87% of the general public.

To illustrate, you wake up and sleep late on the weekends (or days off) and then abruptly fall back to an early-to-rise, early-to-sleep schedule when the workweek commences. Unsurprisingly, you find it hard to fall asleep on Sunday night and feel worse for wear on Monday morning.

Fret not, our in-depth guide shows you how to combat social jetlag with simple tweaks to your routine.

22. Virtual Jet Lag

No thanks to the coronavirus, there’s now a third form of jet lag known as virtual jet lag or “digital” jet lag. Instead of being physically present in a different time zone, you’re now virtually experiencing the jet lag in the comfort of your home through 1 a.m. Zoom meetings and 6 a.m. Skype calls, to name a few.

To tone down the worst of virtual jet lag, bolster your sleep hygiene defenses to keep sleep debt low and your body clock circadianally aligned to the best of your abilities.

23. Shift Work

Shift work duties also take a toll on your body clock as you work hours at odds with your circadian rhythm. You likely feel sleepy at work when it’s dark outside, and have trouble sleeping when you’ve knocked off and it’s light outdoors. The lack of sleep then blossoms into ever-burgeoning sleep debt.

Eating meals at consistent times and during the day, even if you’re a night shift worker, can help keep your body clock aligned.

24. Daylight Saving Time (DST)

Daylight saving time (DST) is the best proof of how a one-hour deviation from your usual sleep schedule upsets your sleep patterns. When DST begins, you lose an hour of sleep as your body clock shifts forward. It’s also likely that you take longer to fall asleep and wake up more often during the night.

At the end of DST, you don’t get an extra hour of sleep despite popular misconceptions — most of us only get about 40 minutes of additional snooze time. Plus, the earlier wake-up time inevitably cuts into your sleep need, so you’re at greater risk of sleep deprivation.

Hop over to our guide on DST to learn how to keep up with the changing times.

25. Revenge Bedtime Procrastination

RISE app photo showing times when your energy is at a peak and when it is low.
The "Melatonin Window" reminder tells you the best time to go to bed so you can fall asleep and sleep through the night more easily to meet your sleep need.

Ever leisurely scrolled on your phone (or consumed other forms of media) late at night to make up for the lost time while you were at work, even though you should be sleeping? That would be revenge bedtime procrastination for you.

Unfortunately, you don’t just lose sleep because of a later bedtime. In fact, you may be missing out on the golden hour of sleep — or what we call the “Melatonin Window” in the RISE app. This is the window of time in which your body produces peak levels of the sleep-promoting hormone. The added blue-light exposure from your digital devices further dilutes the melatonin content in your system. As a result, you take much longer than usual to fall asleep, delaying an already delayed bedtime.

The solution: Prioritize an evening wind-down to satisfy your need for me-time/downtime after work.

26. An Inaccurate Sleep Score

Your tracker’s sleep score may be misleading you — and causing unnecessary worry that holds you back from sleep — even when you’ve slept well.

Most sleep tracking apps and devices on the market focus on “sleep quality,” even though sleep scientists have yet to agree on an official definition. Unless you’re hooked to the right equipment in a comprehensive sleep study, your sleep tracker just isn’t measuring your sleep stages accurately, no matter what the marketing ads claim.

Instead of losing sleep over dubious sleep metrics, the only sleep score you need to focus on is sleep debt, which is the premise of the RISE app.

27. The Monthlies

To the ladies who complain of mediocre sleep during your period, know that you’re not alone.

Women generally suffer from more sleep disturbances during that time of the month and the week before it. Between the period cramps, back pain, headaches, mood swings, hormonal changes, and carb cravings, it’s no wonder the fairer sex has more difficulty snoozing.

That’s why we wrote a post on how keeping sleep debt low helps you during your period.

28. Menopause

The bad news is that ladies aren’t free from their sleep problems once they enter menopause.

Blame your substandard sleep on the hormonal changes manifesting as hot flashes and night sweats that raise your CBT in rebellion to sleep. The accompanying joint pain and increased nighttime urination also mean you have a harder time falling and staying asleep through the night.

To make matters worse, these biochemical alterations subject you to anxiety and depression, which we all know aren’t the best ingredients for a good night’s sleep. Research also warns that menopause is associated with various sleep disorders, such as insomnia, restless legs syndrome, and sleep apnea, that infamously hinder sleep.

While some women have tried hormone replacement therapy and antidepressants, CBT-I is still your best bet for better sleep tonight.

29. Pregnancy

Many pregnant women are too well-acquainted with sleep problems for their liking. The bodily changes they endure to support healthy fetal development are the very same ones sabotaging their snooze time. Morning sickness, leg cramps, a frequent urge to pee, and restless legs syndrome are just some of the reasons why a lack of sleep is commonplace among the pregnant populace.

If you wish to minimize your sleep debt to avoid complications like miscarriages and high-risk pregnancies, check out our post on “How to sleep when pregnant.”

30. You’re a New Parent

After pregnancy, you aren’t out of the woods with your sleep troubles — in fact, they may have only intensified, courtesy of your newborn. To illustrate, the prevalence of insomnia after childbirth was as high as 41-60%, with a short sleep duration averaging 6-7 hours.

From the frequent diaper changes to the round-the-clock feedings, you’re bone-weary tired from the lack of sleep. Even if you’ve managed to doze off (not a difficult feat, if we’re being honest), you probably experienced fragmented sleep that’s unlikely to satisfy your sleep need.

For sleep-deprived new parents, the American Sleep Association (ASA) recommends maximizing your sleep time with close adherence to good sleep hygiene practices, which our step-by-step Sleep Guide can help.

31. You’re on Vacation

Before you raise your brows in skepticism, hear us out.

Being on vacation thrusts your sleep self into an entirely new environment that it needs time to adapt to, on top of the travel jet lag. Even on the plane, the reduced oxygen levels can induce hypoxia (especially on long-haul flights), which disrupts sleep.

On the flipside, the lack of daily stressors may mean you snooze better during your getaway. As with many things in life, your sleep mileage may vary. To boost your odds of better sleep in your hotel room or Airbnb, check out our tips for the perfect sleeping environment.

Why Can’t I Sleep? (Hopefully,) Mystery Solved

As you’ve learned, the processes regulating sleep — namely, sleep homeostasis and the circadian rhythm — are complex and susceptible to interference. There could be many factors why you can’t sleep, some with their own mutually reinforcing vicious cycles, like caffeine and late-night anxiety.

Thankfully, decades of scientific research on healthy sleep hygiene provide a blueprint for inspecting your daily and nighttime habits to get to the bottom of why you can’t sleep.

A tool like the RISE app simplifies the science to help you uncover potential issues related to poor sleep. More importantly, its easy-to-use interface and 20+ science-backed habits keep you accountable in your journey to better sleep every night.

Summary FAQs

Why can’t I sleep even though I’m tired?

Circadian misalignment is the major culprit, in which your internal body clock is out of sync with the external light-dark cycle. It could also be due to poor mental health, in which chronic stress and anxiety mean your brain is too wired for sleep. On top of that, unhealthy sleep habits like drinking caffeine or napping too late in the day are also to blame.

What to do when you can’t fall asleep?

Give yourself sufficient time to wind down before you sleep. Unplugging and slowing down help put you in the right frame of mind for sleep. You can take a warm bath, read a non-stimulating book, or try relaxation techniques. If you wake up in the middle of the night and can’t fall asleep, do a sleep reset. Get out of bed and do something relaxing like listening to calming music. Once you start to feel drowsy, head back to bed.

Why can’t I sleep at night but can during the day?

One of the primary reasons is an out-of-balance circadian rhythm. It could also be a case of travel jet lag, in which your body clock isn’t up to speed with the new time zone yet. Certain medical conditions and sleep disorders, like obstructive sleep apnea and insomnia, can incite excessive daytime drowsiness too. The lack of healthy sleep hygiene further worsens the problem.

Sleep better. Sell more.

Learn more about Rise for sales teams.

Thanks! We received your information. You'll hear from us shortly.
Oops! Something went wrong while submitting the form.
About Rise
Rise is the only app that unlocks the real-world benefits of better sleep.

Instead of just promising a better night, we use 100 years of sleep science to help you pay down sleep debt and take advantage of your circadian rhythm to be your best.

Over the past decade, we've helped professional athletes, startups, and Fortune 500s improve their sleep to measurably win more in the real-world scenarios that matter most.

Rise Science is backed by True Ventures, Freestyle Capital, and High Alpha; investors behind category winners Fitbit, Peloton, and Salesforce Marketing Cloud.
Try 7 days free

The power behind your next best day

RISE makes it easy to improve your sleep and daily energy to reach your potential

RISE app iconApp store icon

Sleep Hygiene

View all