Why Can’t I Sleep? 10 Common Reasons & How to Fix Them

1. Stress and Anxiety

Stress is enemy number one for sleep. When your mind is racing with worries – about work, finances, school, or anything in life – it becomes very hard to relax enough to fall asleep. Anxiety triggers the body's "fight or flight" response, keeping stress hormones like cortisol elevated. This physiological arousal means your heart rate stays up and your mind stays alert when it should be winding down. It's no surprise that stress and anxiety often lead to insomnia. In fact, many people experience temporary insomnia during periods of high stress (think relationship troubles or job changes).

How to fix it: While you might not eliminate all stress, you can change how you manage it at bedtime. Try establishing a relaxing wind-down routine: dim the lights, do some deep breathing or meditation, or take a warm bath in the evening. Controlled breathing exercises and progressive muscle relaxation can calm a racing mind and lower physical tension. Journaling before bed is another effective strategy – write down your worries or a to-do list for tomorrow to get them off your mind. If anxiety is a chronic issue, consider speaking with a professional; therapies like cognitive-behavioral therapy can help control anxious thoughts that interfere with sleep.

Bottom line: create a buffer between your stressful day and your bedtime. Even 15 minutes of a calming activity can help ease anxiety so you can drift off more peacefully.

If you're having trouble falling asleep, our article on how to fall asleep faster provides practical tips to help you drift off more easily.

2. Irregular Sleep Schedule and Poor Routine

Our bodies crave consistency. If you're constantly changing your sleep schedule – going to bed at 9 PM one night and 1 AM the next, or sleeping in very late on weekends – you're likely confusing your internal clock. An inconsistent sleep schedule can make it difficult to fall asleep when you want to. Similarly, not having a bedtime routine (or having an overly stimulating one) can keep your mind too alert at night. For example, doing work emails or intense gaming right before bed can thwart the transition to sleep.

How to fix it: Aim to keep a regular sleep schedule, even on weekends. Try to go to bed and wake up at roughly the same times every day. This consistency strengthens your circadian rhythm, training your body when it's time to sleep and wake. In addition, develop a gentle bedtime routine to cue your body that it's bedtime. Over 30–60 minutes, do calm activities like reading a book, listening to soothing music, or gentle stretching. Avoid anything overly exciting or stressful during this wind-down period. If your schedule has been out of sync (like after travel or all-nighters), you may need to reset your sleep schedule – see "How to Reset Your Sleep Schedule (Circadian Rhythm Reset)" for tips on shifting your sleep times gradually. With a consistent schedule and relaxing pre-bed habits, your body will start feeling sleepy at the right time each night.

Understanding the different stages of sleep, particularly what is REM sleep, can help you appreciate why good sleep quality is important for your overall health.

3. Too Much Screen Time and Blue Light at Night

If you're scrolling through your phone or watching TV late into the night, this could be a major reason you can't sleep. Electronic screens emit blue light, a wavelength that suppresses melatonin (the hormone that makes you sleepy). Exposure to bright screens in the evening essentially signals your brain to stay awake. Additionally, engaging content – whether it's an intense movie, an addictive video game, or social media feeds – keeps your mind stimulated when it should be powering down. The result is that you climb into bed with an alert brain that refuses to shut off.

How to fix it: Implement a "digital curfew." Try to turn off or put away phones, tablets, computers, and TVs at least an hour before bedtime. Instead, use that time for low-tech wind-down activities (reading a paperback, talking with family, taking a shower, etc.). If you must use devices at night, consider tools like blue-light-blocking glasses or enabling night mode on screens – these can reduce blue light exposure, though it's still better to avoid screens altogether if you're struggling with sleep. Also, keep devices out of arm's reach when you go to bed. The temptation to check messages or scroll can prolong your sleeplessness. By breaking the late-night screen habit, you remove the artificial "daylight" that has been tricking your brain and allow melatonin to do its job, helping you fall asleep faster.

If your sleep schedule has been disrupted, you might want to learn about how to reset your sleep schedule to get back on track.

4. Late Caffeine or Other Stimulants

That 4 PM cup of coffee might be contributing to your 11 PM insomnia. Caffeine is a potent stimulant that can stay in your system for many hours. For some people, consuming caffeine even 6 hours before bedtime can reduce total sleep time and sleep quality. It's not just coffee – tea, soda, energy drinks, and even chocolate contain caffeine. Similarly, nicotine (from cigarettes or vaping) is a stimulant that can keep you awake. Even certain medications (like decongestants or ADHD medications) have stimulating effects. Using these too close to bedtime will rev your body up when it should be winding down.

How to fix it: Be mindful of when you have your last dose of caffeine each day. A good rule of thumb is to avoid caffeine in the late afternoon and evening. Many experts suggest cutting off caffeine at least 6–8 hours before bed. So if you aim to sleep at 11 PM, try not to have caffeine after 3–5 PM. If you crave a hot drink in the evening, go for decaf coffee, herbal tea, or warm milk instead. The same goes for nicotine – avoid smoking or vaping late at night (and better yet, consider quitting for your health and sleep). Check any medications or supplements you take for stimulating ingredients and ask your doctor if you can take them earlier in the day. By eliminating stimulants in the hours leading up to bedtime, you give your body a chance to naturally slow down and feel sleepy.

5. Drinking Alcohol Before Bed

Many people think a nightcap (a glass of wine or whiskey) will help them sleep. It's true that alcohol can make you feel drowsy initially – you might fall asleep faster – but it actually disrupts your sleep later in the night. Alcohol is known to fragment sleep and can reduce the important REM stage of sleep. As the alcohol wears off in the middle of the night, you may find yourself waking up more easily, tossing and turning, or needing to use the bathroom. It can also worsen snoring and sleep apnea in some individuals. The result: you sleep less soundly and wake up feeling unrefreshed.

How to fix it: Moderation and timing are key. If you drink alcohol, avoid having drinks in the last 2-3 hours before bedtime. A drink with dinner (several hours before bed) is generally better than a drink at 10 PM. Giving your body time to metabolize alcohol before you sleep will minimize disruptions. Better yet, limit alcohol intake overall on evenings when you need a good sleep. Instead of relying on alcohol to relax you at night (since it's a false friend for sleep), try non-alcoholic calming drinks like chamomile tea or practice relaxation techniques. You'll likely notice you sleep more deeply without alcohol in your system. Cutting out that bedtime wine or beer could remove the very thing that's been causing you to wake up at 3 AM.

6. Uncomfortable Sleep Environment (Light, Noise, Temperature)

Your bedroom itself might be the culprit behind your sleepless nights. If the room is too bright, too noisy, too hot or cold, or your bed is uncomfortable, falling and staying asleep becomes a challenge. For instance, light filtering in (from streetlights or early morning sun) can suppress melatonin and wake you up. Noise – anything from traffic to a snoring partner – can keep your brain on alert, preventing deep sleep. A room that's warm and stuffy can cause restlessness, as our bodies tend to sleep best in a cooler environment (around 65°F or 18°C is often cited as ideal). And don't overlook your mattress and pillow: if they're old, saggy, or not suited to your preference, you might be physically uncomfortable and wake with aches.

How to fix it: Optimize your sleep environment for comfort and minimal disturbance. Make the room dark – use blackout curtains or an eye mask to block light. Make it quiet – earplugs or a white noise machine/fan can help mask disruptive sounds if you can't eliminate them. Set the temperature to a cool, comfortable level (most people sleep better in a slightly cool room, around 60-67°F). Ensure you have a supportive mattress and pillow that suit your needs; if your bed is causing you back or neck pain, consider investing in new bedding. Also, keep your bedding and sleepwear appropriate for the season (breathable fabrics, not too many blankets in summer, etc.). A comfortable, dark, quiet, and cool bedroom signals your body that it's time for sleep and makes it easier to drift off. Small changes like installing a darker shade or turning down the thermostat could have a surprisingly big impact on your sleep quality.

7. Jet Lag or Shift Work (Circadian Disruption)

If you've traveled across time zones recently or you work night shifts/rotating shifts, your body's internal clock might be out of sync with the local time. Jet lag occurs when you fly across time zones – your body is still on your "old" time, so you may not be sleepy at night in the new time zone, or you might wake up at odd hours. Shift work (like working overnight or early morning shifts) similarly forces you to be awake when your body expects to be sleeping, and vice versa. These situations can lead to pronounced insomnia because your circadian rhythm is misaligned with day and night. Night shift workers, for example, often have trouble falling asleep during daylight and may get fragmented, insufficient sleep during the day.

How to fix it: For jet lag, the best remedy is to gradually adjust to the new time zone. Get exposure to daylight at your destination (morning light helps if you need to shift your clock earlier). Try to stay awake until the local bedtime and avoid naps longer than 20-30 minutes, which can delay adjusting. Melatonin supplements, taken at the target bedtime of the new time zone, can also help cue your body to the new schedule (use them short-term, and consult a doctor if needed). For shift work, it's more challenging since the schedule is ongoing. If you work nights, wear dark glasses on the commute home to avoid morning light that can wake you up, and make your bedroom dark and quiet to simulate night during the day. Stick to a set sleep routine even on off days if possible. Some shift workers use bright light therapy at the start of their shift to help them feel alert, and then take melatonin in the morning to help day-sleep. It may also help to nap strategically (a brief nap before a night shift can reduce sleepiness on the job). Check out our article How to Reset Your Sleep Schedule (Circadian Rhythm Reset) for more detailed strategies on adjusting your body clock. While you may not eliminate all jet lag or shift-related issues, these techniques can minimize the disruption and help you get better rest.

8. Napping Too Late or Sleeping In

Short power naps can be refreshing, but long or late-afternoon naps might be robbing you of sleep at night. Napping late in the day can confuse your internal clock and reduce your sleep drive (the biological urge to sleep that builds up the longer you're awake). For example, if you take a two-hour nap in the evening, your body might not be ready to fall asleep again at bedtime, just as a long evening "snack" can spoil your appetite for dinner. Similarly, sleeping in very late in the morning can make it hard to fall asleep the next night at your normal time, creating a cycle of insomnia. While catching up on sleep is important, drastically oversleeping on weekends can backfire by disrupting your rhythm.

How to fix it: Use naps wisely. If you're extremely tired and need a nap, keep it short (20-30 minutes) and early in the afternoon (for instance, a quick nap around 1-2 PM after lunch). This gives you a boost without entering deep sleep or REM that can make you groggy or steal from nighttime sleep. Avoid napping in the late afternoon or evening – after ~3 PM, skip the nap and push through until bedtime. As for mornings, try to maintain a consistent wake-up time. It's tempting to stay in bed, but getting up at a reasonable hour (within an hour of your usual wake time) helps set your sleep drive for the next night. If you had a late night and need to recover, a slight sleep-in is okay, but don't prolong it into the afternoon. By controlling naps and wake times, you'll ensure you're sleepy when night comes. Over time, you'll find it easier to fall asleep because you haven't accidentally "pre-filled" your sleep need during the day.

9. Medical Conditions or Pain

Sometimes the reason you can't sleep isn't about habits at all, but about your health. Chronic pain conditions like arthritis, back pain, or headaches can make it hard to get comfortable enough to fall asleep. Or, you may fall asleep only to be woken up by pain in the night. Other medical issues can interfere too – for example, people with acid reflux might wake with heartburn when lying down, and those with frequent need to urinate (nocturia) will find their sleep constantly interrupted. Respiratory problems (like asthma or allergies) can worsen at night and cause breathing difficulty that interrupts sleep. Additionally, neurological conditions (like Parkinson's or Alzheimer's) and hormonal changes (like menopause, which can bring night sweats) often have sleep disturbance as a symptom.

How to fix it: If you suspect a medical issue is behind your insomnia, it's important to address that underlying condition. Talk to your healthcare provider about your sleep troubles and symptoms. Treating the pain or illness can significantly improve sleep – for instance, proper pain management (medication, physical therapy, etc.) can make nights much more comfortable. If acid reflux keeps you up, dietary changes or medications and propping up your upper body can help. For nighttime urination, limiting fluids in the evening and addressing any bladder/prostate issues can reduce wake-ups. Make sure any chronic conditions (diabetes, thyroid issues, etc.) are well-controlled with treatment, as this often leads to better sleep. In some cases, adjusting the timing of medications can help (some meds can cause insomnia as a side effect – your doctor might switch you to morning dosing or an alternative drug). The bottom line is to work with a medical professional. Improving or managing the health condition will likely improve your sleep, and in turn, better sleep can often improve the condition – a virtuous cycle.

10. Underlying Sleep Disorders (Insomnia, Sleep Apnea, etc.)

If you've ruled out all the lifestyle and environmental factors and still lie awake, you might be dealing with a specific sleep disorder. One common disorder is insomnia itself – a condition where you regularly have trouble falling or staying asleep even when you give yourself enough opportunity (we cover insomnia in depth in What is Insomnia? Causes, Symptoms, & Treatments). Insomnia can start due to stress or poor habits but then take on a life of its own. Another very common sleep disorder is obstructive sleep apnea, where breathing repeatedly stops and starts during sleep. People with apnea often wake up gasping or snorting (though they may not remember all awakenings) and feel unrefreshed despite spending adequate time in bed. Restless legs syndrome (RLS) is another – an uncomfortable urge to move the legs that strikes in the evenings and can prevent falling asleep. Other disorders include circadian rhythm disorders (your internal clock is off schedule) or parasomnias (like night terrors or sleepwalking).

How to fix it: If you suspect a sleep disorder, it's important to seek evaluation from a doctor or sleep specialist. Signs of a sleep disorder include: chronic difficulty falling or staying asleep, excessive daytime sleepiness, loud snoring with pauses in breathing, or unusual behaviors during sleep. A sleep study (polysomnography) might be recommended to diagnose conditions like sleep apnea. Treatment options vary by disorder – for example, CPAP machines for sleep apnea, medications or behavioral therapy for insomnia, or specific medications for RLS. The key is getting a proper diagnosis, as sleep disorders often require specialized treatment. Don't hesitate to seek help if you suspect a sleep disorder – effective treatments are available, and addressing the underlying condition can dramatically improve your sleep quality and overall health.

For more information about sleep disorders, check out our article on what is insomnia to understand the different types and treatments available.