Why Can't I Sleep? Reasons for Trouble Sleeping

A photograph of a man lying awake in a rumpled bed.

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Do you often find yourself asking "Why can't I sleep?" or "Why am I more tired when I wake up than when I went to bed?" There are many potential reasons why someone may be having trouble sleeping. Each one can make a good night’s rest more elusive than half-remembered dreams.

If you’ve been having a tough time falling or staying asleep, chances are the cause is either something you’re doing (like drinking coffee late in the day) or something you’re not doing (like getting rid of the stress that keeps you awake). Fortunately, there are a number of steps you can take to turn things around.

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Signs of Sleep Problems

There are some common signs that you are having trouble sleeping, many of which show up during the day. You may notice:

If you can't sleep at night, you might also find that you feel groggy and drowsy most of the next day. You may even drift off during the daytime or consume excessive amounts of caffeine to try to stay awake.

Reasons You Can't Sleep

There are many different factors that might be contributing to trouble with sleep. Lifestyle choices, sleep habits, stress, and medical conditions can all play a role.

Alcohol

A single glass of alcohol before bedtime may not interfere with your ability to fall asleep, but indulge in much more and sleep can become impaired. This is because alcohol interferes with the sleep cycle, especially the REM sleep that includes dreaming.

You may not realize this since the initial effect of drinking alcohol is relaxation. This can help you drop off to sleep quickly after imbibing. But your rest will be fragmented and unrefreshing. This effect is even more prevalent with people with high alcohol use as this often goes hand-in-hand with insomnia.

If you drink a lot of alcohol at night, you’re also more likely to wake up mid-sleep to use the bathroom, which can reduce your sleep quality.

Anxiety

Sleep and anxiety are closely connected. If you have trouble sleeping, your anxiety might increase, and if you have high anxiety, you may have trouble sleeping. In fact, sleep disruption can co-occur with almost all mental health conditions.

Research shows that the type of sleep disruption varies based on anxiety type. People with state anxiety (anxiety due to a current situation) typically have more trouble falling asleep. People with trait anxiety (a personality that is more anxious) often have more trouble staying asleep.

Sleep Habits

Sleep habits, such as staying up too late and having an irregular sleep schedule, can play a part in poor sleep. Napping later in the day can lead to trouble sleeping as well.

Along with trouble falling or staying asleep, poor sleep habits can also negatively affect mental health. Studies have connected poor sleep hygiene with poorer mental wellbeing.

Bed Sharing

Sharing your bed, whether with a human or four-legged friend, greatly reduces sleep quality—especially if your partner snores, crowds you, hogs the covers, or otherwise makes you uncomfortable. You and your human partner might also have different preferred sleeping conditions (such as temperature, light, and noise level).

Sharing a bed with an infant can also lead to more fragmented sleep for the parent and more night wakings for the child. Sleeping in an adult's bed can also be dangerous for the baby, potentially leading to asphyxia or suffocation. The American Academy of Pediatrics recommends that babies always sleep in their own crib.

Sleep Temperature

Many sleep experts recommend keeping your bedroom at 60 to 67 degrees Fahrenheit at night. But many people like to cut energy costs by turning the thermostat down to the freezing zone during the winter and switching the AC off during the summer.

Both of these extremes hijack your trip to the land of Nod, however. Your body needs to cool slightly at night for the most refreshing sleep, which is impossible in an overly heated bedroom. A too-cold room, on the other hand, will wake you up.

Caffeine

You know a bedtime cup of coffee is a bad idea, but did you know that the half-life of caffeine is three to five hours? That means only half the dose is eliminated during that time, leaving the remaining half to linger in your body. That’s why a late afternoon cup of joe can disrupt your sleep later that night.

Caffeine has been associated with having a tougher time getting sleep, less total time asleep, and worsened perceived quality—even more so in older adults as this demographic tends to be more sensitive to this substance.

Stress

If "I can't sleep" is followed by "I'm so stressed," you're not alone. About 43% of American adults say that stress has kept them up at night at least once in the last month.

During the day, the activities of life tend to distract you, but once you settle yourself into bed, your mind is free to roam. For most people, it’s not the good aspects of their lives that their mind chooses to focus on, but rather, the negatives. This can keep them from getting a good night's sleep.

Exercise

A casual around-the-block stroll with your dog in the late evening is fine (especially if it shifts your pet's wake-up time closer to your own). But research has found that a heart-pumping, sweat-dripping cardio workout within one hour of bedtime is too much.

Your body temperature and heart rate naturally drop as you fall asleep. Exercise raises those two body functions and stimulates your entire nervous system, making it tough to snooze.

Diet

Is your typical bedtime snack a slice (or two) of pizza or a bag of chips? If so, don’t be surprised when you’re lying awake staring at your ceiling.

A full load of fat or protein right before bedtime, or a spicy meal, can send your digestive system into overdrive, making it difficult to sleep and potentially giving you heartburn. Hunger pains can wake you up as well, as can precipitous blood sugar drops during the night.

Medications

Do you take any medications? If so, this may be the reason why you can't sleep. Drug-induced insomnia can be caused by a variety of prescription medications, including medicines for:

Screen Time

Light exposure at bedtime impairs your quality of sleep, whether it’s coming from your bed partner’s reading lamp, the alarm clock display, or the street light outside your window. Light emitted from electronic devices can have the same effect, making this an issue if you like to watch television or use your smartphone right before bed.

Studies have connected longer screen times with a harder time falling asleep, shorter sleep durations, lower sleep efficiency, and worsened sleep quality.

It is important to note that other factors—including sleep disorders and depression—can also make sleep difficult. If you suspect that a medical or mental health condition is contributing to your poor sleep, talk to a healthcare provider.

Impact of Poor Sleep

Sleep deprivation can have a wide range of negative health effects. Notable physical and mental health consequences of not getting enough sleep include:

In addition to these health problems, lack of sleep is also connected to an overall decrease in quality of life and a greater risk of death.

What Should I Do If I Can't Sleep?

The first step to take if you can't sleep: Work to alleviate some of the sleep-stealers that are affecting your rest. These strategies can improve the amount and quality of sleep that you get each night:

  • Limit alcohol use, especially in the evening.
  • Give your pets beds of their own, encourage your snoring partner to sleep on their side, and use a white-noise machine to block out sound.
  • Adjust your thermostat to avoid being too hot or too cold. If that's not possible, wear thick socks and use cozy blankets during cold snaps and turn on a fan in the summer. 
  • Turn off electronics at least an hour before bedtime.
  • Hang blackout shades or curtains in your bedroom and close the door to shut out light.
  • Although caffeine’s effects depend on your tolerance, the dose, and your age, it is best to keep your consumption below 400 mg per day and stay away from caffeine sources within six hours of bedtime. 
  • If you're struggling with stress, try a daily meditation practice. You don’t need to be an expert yogi or spend hours sitting on a mat. Even 10 minutes a day is beneficial. 
  • Schedule your workout for the morning or hit the gym during your lunch hour. If you do exercise at night, don't do your workout within an hour of bedtime.
  • Have a small snack before hitting the hay that is heavier on complex carbs and lighter on protein (but includes both). Good choices include a small bowl of whole-grain cereal and milk, a slice of deli turkey wrapped around a celery stick, or a piece of fruit spread with peanut butter.

Frequently Asked Questions

  • Why can't I sleep even when I'm tired?

    Some of the most common reasons for insomnia—even when you're tired—include being under a lot of stress, having an irregular sleeping schedule or poor sleep habits, mental health issues, physical illness, medications, and sleep disorders.

    If you're having trouble sleeping, talk to a healthcare provider. They can help hone in on the reason why you're having trouble sleeping as well as provide some guidance for getting a better night's rest.

  • Why can't I sleep through the night?

    If you wake up during the night, this could be due to growing older, a medication you're taking, your lifestyle (such as drinking alcohol before bedtime or napping a lot), or an underlying condition.

    Try correcting poor sleep habits and see if your sleep improves. If it doesn't, a healthcare provider can help determine the cause of your sleep issues.

  • Why can't I sleep on my back?

    You might find sleeping on your back uncomfortable if you have back pain or are used to other sleeping positions. If you'd like to sleep on your back, try placing a pillow under your knees and/or lower back. This should help.

    However, back sleeping isn't recommended for everyone, such as those who are pregnant, those with obstructive sleep apnea, chronic snorers, or people with heartburn.

  • Why can't I fall asleep?

    Trouble falling asleep can be caused by having a lot on your mind, a bed partner who snores, late-day naps, or spending time on your phone or watching television right before bed. An irregular sleep schedule may also make it harder to fall asleep. Studies have also connected certain health conditions with sleep onset problems, such as attention-deficit hyperactivity disorder (ADHD).

  • Why can't I go back to sleep?

    If you wake up in the middle of the night and find it hard to go back to sleep, it's possible that your inability to return to rest is due to watching the clock or thinking about things that tense you up.

    If you are a light sleeper, you might also find it difficult to return to sleep after hearing a noise, such as having a notification go off on the cellphone by your bed. An inability to turn your mind off once it's awakened may make it hard to let your troubles go long enough to drift off to sleep.

A Word From Verywell

If you are wondering why you can't sleep, the first thing to do is assess and address any lifestyle factors that might be interfering with a good night's rest. If you don't find any relief after making these changes, talk to a healthcare provider. They can help get to the bottom of your sleep difficulties and find the appropriate treatment so you can get the rest you need.

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