This is why you randomly wake up at 4 a.m. (and how to fall back asleep fast)

Waking up in the middle night typically isn’t cause for concern. The average person wakes up several times throughout the night, but often doesn’t notice because they’re able to fall back asleep quickly (and they’re only awake for a few seconds). However, frequent night awakenings could also be a sign of insomnia, which has been found in 40% of older adults. But before you self-diagnose, it could be helpful to take a look at why you’re waking up in the middle of the night.

What causes you to wake up in the middle of the night

As it turns out, there are multiple reasons why we randomly wake up in the middle of the night, including, but not limited to:

• Noise: This could be from the sound of traffic outside and birds chirping, or your partner snoring next to you (or, as was often the case for me, a noisy upstairs neighbor). “The brain continues to register and process sounds during sleep, and as such, noise can be a major sleep stealer,” explains Terry Cralle, registered nurse and representative of the Better Sleep Council.
• Alcohol: A glass of wine with dinner may not seem like a bad idea, but as alcohol metabolizes in your system, it can disrupt your sleep, which can lead to tossing and turning and frequent awakenings. “Alcohol consumption is known to reduce the time spent in REM [rapid eye movement] sleep and is also considered a diuretic, which may lead to middle-of-the-night bathroom trips,” says Cralle.
• Dinnertime: Eating too close to bedtime can also lead to waking up in the middle of the night due to heartburn and acid reflux. 
• Stress: If earlier-than-usual awakenings are not your norm, you may consider what’s going on during waking hours and if stress from life or work may be impacting your sleep.
• Aging: As we get older, our quality of sleep tends to diminish as our sleep cycle changes and medication can impact your sleep schedule as well.

How to fall asleep quickly after waking up in the middle of the night

If you have a few more hours before your alarm is scheduled to go off, you can still salvage some of your sleep. Here’s how:

Resist the temptation to watch the clock

Checking the time (or notifications) can actually cause you to stay awake longer. “The light is disruptive and you may easily wind up checking content and before you know it, you have easily lost an hour (or more) of sleep,” says Cralle.

Avoid bright light

If you need to get up and go to the bathroom in the middle of the night, try to avoid bright lighting as much as possible. However, if you find yourself making several trips throughout the night, you should consult your healthcare provider.

Try to relax (but don’t force yourself to fall asleep)

Anyone who has ever found themselves staring at their ceiling in the middle of the night knows purposely trying to fall asleep can often lead to the opposite happening. Instead of forcing sleep, experts recommend trying relaxation techniques instead, such as deep breathing, meditation or progressive muscle relaxation, which involves tensing and then releasing each muscle in your body.

Leave the room

If all fails after 20 minutes, get up and go to another room to read or listen to soft music. Whatever you do, just make sure it’s in another room. “Doing this will lead your brain and body to associate your bed with wakefulness instead of with sleep,” Johns Hopkins sleep expert Luis F. Buenaver, Ph.D. said in a blog post.

“It can be difficult leaving a warm, comfortable bed after waking up in the middle of the night. But think of this step as an investment in better sleep—if not tonight then tomorrow night and in the future.” Once you’re sufficiently sleepy, you can return to your bedroom.

Tips to prevent waking up in the middle of the night

While occasional 3 a.m. awakenings may be unavoidable, there are science-backed ways to ensure you set yourself up for success before bedtime. For adults under 65, it’s recommended you get seven to nine hours of sleep per night with the goal of going to sleep within two to three hours after sunset. 

It’s essential to go to sleep before midnight, Dr. Allison Brager, a neurobiologist with expertise in sleep and circadian rhythms, previously told Fortune, as this “optimizes time spent in restorative non-REM sleep.” Other tips for getting a good night’s rest include:

• Keep a regular bedtime and wake time
• Get light exposure, ideally sunlight, during the morning
• Avoid large doses of caffeine throughout the day, but especially after 2 p.m.
• Avoid large meals, alcohol and exercise close to bedtime
• Avoid bright light exposure in the evening
• Keep your bedroom dark and cool

Additionally, you can optimize your bedroom to include sleep masks and ear plugs; blackout curtains; a noise machine and/or other sound-absorbing materials, such as carpet, area rugs or wall hangings; and a comfortable sleep surface, such as mattress, pillows and bedding, to help you fall asleep (and stay asleep) more easily.

But if nothing’s working and you still find yourself getting up at 4 a.m. more often than not, then you’ll want to check with your doctor to see if you have a sleep disorder.

“Quality sleep is the foundation on which optimal health is built. Even if nutrition and exercise are at their best, without proper sleep their benefits are greatly reduced,” Dr. Abhinav Singh, medical director, Indiana Sleep Center, expert at SleepFoundation.org, and co-author of Sleep to Heal: 7 Simple Steps to Better Sleep, previously told Fortune. “Sleep is important for metabolic health, immune health, muscle repair, optimal brain function and mental health. Optimal sleep not only adds years to your life, but life to your years.”