What To Do When You Can’t Sleep: 21 Researched Tips | Casper

June 24, 2021 | Casper Editorial Team

Do you lay in bed for hours but can’t seem to fall asleep? If you’re one of the 68% of Americans who struggle to fall asleep at least once a week, you’ve likely experienced the frustrations of tossing and turning at night to no avail.

Whether you’re in need of a super-soft pillow or just need your brain to slow down and relax, lying awake at night can be not only uncomfortable — it can even affect your mental well-being and performance the next day.

So what do you do when you can’t sleep? Here are some common culprits that might be keeping you up, along with our tips to help you fall back asleep.

Reasons Why You Can’t Sleep

If you’re having trouble catching Zs, you might want to think about the root cause of your poor sleep struggles. Is it a physical issue, like being uncomfortably warm or having a backache? Or does it stem from mental stimulation like tech before bed, anxiety, or a big life change? Check out these common reasons for why you’re struggling to fall asleep, and what to do when you can’t get restful sleep.

Reason #1: It’s Too Hot

While some might think that you want to be warm and cozy at night, it’s actually better to sleep in a cool room around 60 to 67 degrees Fahrenheit. When you sleep hot, it can cause things like night sweats that can disrupt your quality of REM sleep.

Reason #2: Blue Light Is Waking You Up

It’s tempting to scroll through social media before hitting the hay, but did you know that the blue light from your screen might be inhibiting your ability to sleep?

Blue light blocks a hormone called melatonin that makes you sleepy, and more than any other color, blue light messes with your body’s ability to prepare for sleep.

Reason #3: You Can’t Get Comfortable

Some nights, you end up tossing and turning for hours, unable to find the best position for sleeping. If you’re not able to get comfortable, you may want to try getting up for 10 to 15 minutes to give your body time to reset.

Reason #4. Stress or Anxiety Is Keeping You Up

Stress or anxiety during the day may cause your mind to race at night. Anxiety before sleep can be caused by too much focus during the day, fear, poor sleep cycles, or rapid thought patterns. It also causes disrupted sleep.

Reason #5: You’re Having Nightmares

Having a nightmare can sometimes cause anxiety about falling asleep again and disrupt your sleep pattern. To help you work past the nightmare, try looking into what your dreams mean to determine the root cause of the issue.

Reason #6: You’ve Had a Big Life Change

A big life change like getting married, starting a new job, or moving to a new city can keep you up at night. Try setting aside time before bed to relax and practice a bedtime routine to get yourself in the mood for better sleep.

Pre-Bedtime Tips To Help Fall Asleep Quickly 

If you’re lying in bed unable to fall asleep, check out these things to do when you can’t sleep.

1. Wait 30 Minutes

If you’ve been trying to fall asleep for a while without luck, you may want to give yourself around half an hour to regroup before trying again, says Michael Perlis, Ph.D., director of the Behavioral Sleep Medicine Program at the University of Pennsylvania. 

Try getting out of bed and moving to a new area of your home to do a relaxing activity like journaling, yoga, or reading. By the time you get back to bed, you’ll have the cold side of the pillow to look forward to. 

2. Keep the Room Cool

To create a comfortable sleep environment, you’ll want to make sure your room is cool and dark at bedtime. Research has found that the optimal temperature for sleep is around 60 to 67 degrees Fahrenheit (15 to 19 degrees Celsius). 

Additionally, you’ll want to make sure there are no bright lights (like a phone screen) that can disrupt your REM sleep. If you want to optimize your bedroom for a peaceful transition between day and night, consider getting a glow light to lull you into a calm, deep sleep.

3. Prioritize Comfort

From your mattress to your pillow, comfort is crucial. If your bed feels like a bed of nails or a marshmallow, it might be time for a change. And remember, cool is cool when it comes to sleep. A cooler room can help lower your body temperature and promote better sleep.

4. Control the Light

Ever tried to sleep with the lights on? Not fun, right? Controlling light in your bedroom is essential. Use curtains, blinds, or a sleep mask to block out unwanted light. And don’t forget about those pesky electronic devices. As we mentioned, their blue light can mess with your sleep, so it’s best to say goodnight to them an hour or so before bedtime. More on that later.

5. Switch Up Your Sleeping Position

Whether you’re sleeping on your stomach, back, or side, it can be tough to switch from what you’re comfortable with. If you’re struggling to fall asleep, you might want to consider testing out a different sleeping position.

While over 55% of people sleep on their sides and 38% sleep on their backs, only 7% of the population are stomach sleepers. While there’s no one-size-fits-all sleeping position, you can set yourself up for success by making sure you have the right type of pillow for your sleeping position.

6. Sleep Solo

While it can be tempting to cuddle with your furry friend, a sleep study from the Mayo Clinic showed that owners wake up more throughout the night when sleeping with their pets. Instead, try snuggling with your pet up until bedtime, then have them switch to their own dog bed so you can catch some peaceful Zs. 

7. Do Calming Yoga

If you’re tossing and turning, it may lead to feelings of restlessness. A great way to counteract this is by doing some calming yoga for sleep to reset your mind and calm your body. 

A recent sleep study found that both resistance exercise and stretching before bed led to significant improvements in chronic insomnia patients — and doing yoga before bed doesn’t mean you need to be a human pretzel. A simple five-minute yoga session with low-intensity positions like child’s pose (Balasana) might just be the thing you need to relax and relieve tension so you can doze peacefully.

8. Try Practicing Mindfulness & Meditation

Mindfulness exercises can help you focus on muscle relaxation and push intruding thoughts from your mind when you can’t fall asleep. Practicing mindfulness has been found to have health benefits such as reducing anxiety, helping manage stress, and increasing your ability to relax.

You can practice mindfulness at any time of day, but spending a few minutes before bed can help put you in the mood when you’re tired but can’t sleep. Here are some prompts to help you practice mindfulness:

  1. Focus on your breathing — is it even and slow or quick and irregular?
  2. Turn your attention to your fingers and toes — are they relaxed?
  3. Hone into your hearing — is there white noise or is it silent?

Meditation is not just for monks in the mountains. It’s a powerful tool that can help reduce anxiety and improve sleep. The key is focusing on the present moment and letting go of the day’s worries. It might take a bit of practice, but the payoff is worth it.

9. Relax Your Muscles

If you’re trying to fall asleep to no avail, you might want to give muscle relaxation methods a shot. Studies have shown that these physical relaxation techniques can help improve the quality of your sleep

One popular muscle relaxation technique is the military method, which involves lying down on your bed and slowly relaxing the muscles in your body, starting with your face and working down to your toes. 

Here’s how to perform the military method when you’re tired but can’t sleep:

  1. Lie down in your bed and release tension from your body.
  2. Start by tensing the muscles in your face then allowing them to relax, and work slowly down your body until you reach your toes.
  3. Once your whole body feels at ease, start to take deep, calming breaths. 
  4. Push all thoughts from your head for 10 seconds. If you feel thoughts intruding, try to focus on a simple scenario like a peaceful lake or open prairie.
  5. Allow yourself to lie in bed with your mind, body, and breath in a relaxed state.

Another popular muscle relaxation technique is progressive muscle relaxation (PMR). PMR involves gradually tensing and releasing muscles throughout your body in sync with controlled breathing. It’s like giving your body a gentle reminder that it’s time to relax and drift off to dreamland.

10. Go Commando

Yes, you read that right. Sleeping in the nude may actually be beneficial for your health — and according to people who sleep nude, most say they do so for comfort. Sleeping naked can help you regulate your body temperature to get closer to that ideal number of 60 to 67 degrees Fahrenheit, and can actually be a biological cue to tell your body that it’s time for sleep. So if you wake up in the middle of the night and stay awake, one potential answer to how to fall back asleep is to sleep in the nude.

11. Do a Body Scan

A great way to relax your body is by doing a self-body scan. Although a body scan might sound like an intimidating test at a hospital, it’s actually a super easy test you can do from the comfort of your own sheets. Like the military method, this type of relaxation technique has been shown to improve sleep quality

To do a body scan, you’ll just want to focus on relaxing one section of your body at a time, until you feel relaxed from head to toe. A body scan is unique because it takes around 10 to 20 minutes, meaning you have ample time to tune in to yourself and slowly relax each muscle.

Here’s how to do a body scan when you can’t sleep:

  1. Lie down in bed.
  2. Starting at the top of your head, focus all your energy on a single part of your body until it feels truly relaxed.
  3. Slowly move down your body, beginning with muscles in the face and neck.
  4. Move down through each arm, and back up through your torso and down your stomach.
  5. Slowly relax each leg, working your way down to your toes.
  6. After approximately 10 to 20 minutes, check in with yourself to see if you notice any lingering tension.

12. Try Journaling

If your mind racing is keeping you up at night, journaling can be a good activity for when you’re tired but can’t sleep. A study showed that journaling about your to-do list before bed can help you fall asleep significantly faster. Next time you’re up counting sheep, consider spending five minutes writing down a specific to-do list for the next few days and see if it helps you catch some Zs.

13. Focus On Your Breathing

Ever heard the phrase, “Just breathe”? It’s not just a cliché. If you’re having trouble sleeping at night, you might want to turn inward and try focusing on your breathing. One way to do this is with controlled breathing methods — or a series of slow, deep breaths that can help you feel calm. Dr. Andrew Weil, Clinical Professor of Medicine at the University of Arizona, suggests using the 4-7-8 method, which uses your breath to help distract you from sleep anxiety. 

Here’s how to practice the 4-7-8 method when you can’t sleep:

  1. Slowly exhale all of your breath until your lungs are completely empty.
  2. Breath in through your nose for four seconds.
  3. Hold your breath for seven seconds.
  4. Exhale for eight seconds.
  5. Repeat this method at least four times.

14. Consider Taking Melatonin

Melatonin is a naturally occurring hormone that can help promote feelings of sleepiness. Over-the-counter melatonin sleeping pills are available as a sleep aid for people who have trouble falling (and staying) asleep.

Melatonin is produced in the pineal gland of your brain, which transforms serotonin into melatonin based on your internal body clock. When melatonin levels rise in your body, your blood pressure and body temperature can lower, helping put you in the mood for sleep. Different factors can affect how long it takes for melatonin sleeping pills to work, such as your age, caffeine intake, light exposure, body size, and tobacco use.

Whether you prefer to listen to sounds of a calming stream, heavy rainfall, or the air conditioner, soft ambient noises have been shown to improve sleep quality and help people fall asleep up to 38% faster. But sleep medication should be your very last resort, as you may not want to become reliant on it.

15. Put Your Phone Across the Room

Out of all the sleep habits, this is one you should strictly adhere to. Scrolling social media before bed has become a commonplace habit for most of us — in fact, 9 out of 10 Americans actually use technology devices before bed. However, using tech before sleeping has been shown to negatively impact sleep quality and may even lead to sleep deprivation. This is partially because of the blue and bright light emitted by screens, which is designed to keep you feeling awake and alert.

If you’re guilty of grabbing your phone after a few minutes of tossing and turning (no judgment), you might want to consider switching off the screen and placing your phone across the room so it’s harder to reach for at night.

16. Listen to Ambient Noise

Different ambient noises, like white, pink, or brown noise, can be helpful to ease sleep troubles. While white noise is often associated with sleep sounds, there are other types of noise that can be great for helping you get a better night’s sleep.

  • White noise: White noise encompasses all sound frequencies, creating a humming sound. Examples of white noise include a fan, TV static, air conditioner, or air purifier.
  • Pink noise: Pink noise has a deeper sound frequency than white noise. Common pink noise examples include rainfall, wind, and rustling leaves.
  • Brown noise: Brown noise is an even deeper frequency than pink or white noise. Brown noise examples include waterfalls and thunder.

Big Picture Tips To Fall Asleep Easily

If you’ve been struggling to fall asleep consistently, you might want to implement these sleep tips throughout your day to set yourself up for a cozy night of disrupted sleep.

17. Practice Sleep Hygiene

Sleep hygiene refers to good behavioral and environmental habits that can lead to a better night’s sleep. The idea behind sleep hygiene is that, by practicing good sleep habits during the day and at night, you can set yourself up for success and better sleep.

Some easy ways to implement good sleep hygiene include:

  • Avoid stimulants before bed: Stimulants like caffeine and alcohol can negatively impact your sleep quality and lead to more sleep disturbances during the night.
  • Reserve your bedroom for sleep and intimacy: Spending too much time during the day in your bedroom can cause you to associate those other activities with your sleeping space. To prevent this, implement a sleep- and intimacy-only rule in your bedroom.
  • Optimize your bedroom layout: To make your bedroom feel like your personal oasis rather than a sleepless night chamber, you’ll want to make sure that your room is optimized for sleep. One of the best ways to do so is to ensure your mattress is the right size for your room. For example, a king size memory foam mattress would feel too small in a 10-by10 room but would look completely at home in a primary bedroom. As a side note, a mattress that’s too firm might be the underlying cause of your sleeplessness. Think of ways to soften it to help you sleep better.

18. Kick the Afternoon Caffeine

Although coffee is typically thought of as a morning beverage, many people grab another cup of joe for an afternoon pick-me-up. However, coffee can stay in your system for up to 10 hours — meaning that 2 p.m. caffeine kick might be keeping you up past midnight.

If you’re used to two or more caffeinated beverages each day, consider swapping your typical afternoon drink for a decaf version instead.

19. Exercise Earlier in the Day

Although a nighttime sweat can increase the amount of deep sleep you get, working out releases endorphins — the “happy hormone” that can sometimes keep you up. According to Charlene Gamaldo, M.D., medical director of Johns Hopkins Center for Sleep, exercise can also raise your core body temperature, signaling to your body that it’s time to be awake. 

To minimize the unintended consequences of a late-night workout, try to end your exercise at least one to two hours before you plan to hit the hay.

20. Limit Your Naps

For nearly one-third of American adults, napping is a common activity. But while some power naps can help you feel rejuvenated and ready to take on the day, consistent napping may inhibit your natural circadian rhythm and cause you to feel more alert at night. 

Studies have shown that quick five-minute naps are too short to allow you to recharge, but naps that pass the 30-minute mark can cause people to feel groggy after waking up. Try to keep your naps in the sweet spot of around 20 minutes, so you wake up feeling refreshed rather than groggy.

21. Create a Better Environment for Good Sleep

Creating a sleep-friendly environment to build good sleep hygiene starts from the ground up. Just like you want your workspace to foster creativity and your workout area to get you pumped, you want your sleep space to feel calm, relaxed, and cozy.

Creating an environment that’s conducive to sleep is individual, and can encompass everything from picking the best bedroom colors for sleep to putting the right plants in your bedroom.

Studies have shown that optimizing your sleep environment by controlling room temperature, humidity, light, and noise levels can increase your quality of sleep.

22. Follow a Consistent Sleep Schedule

While your sleep schedule can sometimes be unpredictable, keeping a general sleep cycle can help you feel more productive and focused and help you develop a fixed sleep pattern. This is because your body runs on a circadian rhythm, an internal clock that naturally tells you when to wake up and go to bed.

However, if you’re used to an inconsistent sleep schedule, you should aim to slowly adjust your routine towards a consistent sleep schedule in around 15-minute increments each night. 

For example, if you normally go to bed at 2 a.m. and wake up at 10 a.m (hey, we’ve all been there), you should start by sleeping at 1:45 a.m, then 1:30 a.m, and so on, until you reach your desired bedtime.

23. Talk to a Sleep Specialist

If you’re struggling with sleep issues, it might be time to go see a sleep specialist about your sleep problem. Sleep specialists are trained to evaluate you to look for deeper conditions like a sleep disorder, and can provide you with more in-depth information that’s specific to your personal needs.

Being tired but unable to sleep is an extremely frustrating situation. While you’re up restless at night, it can feel even more difficult to wake up the next morning. Whether it’s a one-time thing or you’re consistently up counting sheep, we hope this guide can help you figure out what to do when you can’t sleep, and give you some tips for how to fall asleep.

Fall Into a Deep Sleep with Casper

In the grand scheme of things, sleep is more than just a fleeting luxury, but an absolute necessity for our overall well-being. So, whether it’s a minor bout of insomnia or a prolonged struggle, remember to take heart! Turn the tables on your sleeplessness by employing these tips and tricks with an open mind. Make your bed a haven of comfort, cultivate mindful habits, and always aim to set the stage for a sound night’s rest. With time and patience, you’ll find that elusive ticket to dreamland and never look back. Trust us, there’s a silver lining in every sleepless night; it’s just a matter of finding what works best for you.

Ready to turn out the lights? Check out our collection of drool-worthy memory foam mattresses and buttery soft bed sheets for the type of sleep that dreams are made of.

Disclaimer: This article is for general information only and is not intended to be medical advice. Consult your physician before taking any supplements, beginning any diet or fitness plan, or adopting any treatment for a health problem.

Sources:

  1. Breus, Ph.D, Michael. 2022. “How to Sleep When It’s Hot Outside.” Sleep Doctor. December 13, 2022. https://sleep.org/articles/does-your-body-temperature-change-while-you-sleep/ 
  2. Breus, Dr Michael, and Dr Michael Breus. 2022. “How Sleeping with Lights on Can Ruin Your Health.” The Sleep Doctor. June 16, 2022. https://thesleepdoctor.com/sleep-environment/light-and-sleep/
  3. Brooks, Amber, and Leon Lack. 2006. “A Brief Afternoon Nap Following Nocturnal Sleep Restriction: Which Nap Duration Is Most Recuperative?” Sleep 29 (6): 831–40. https://doi.org/10.1093/sleep/29.6.831 
  4. “Charlene Gamaldo, M.D., Professor of Neurology.” n.d. Johns Hopkins Medicine. Accessed July 28, 2023. http://www.hopkinsmedicine.org/profiles/results/directory/profile/0019244/charlene-gamaldo 
  5. Conrad, Melissa. 2005. “Progressive Muscle Relaxation for Stress and Insomnia.” WebMD. WebMD. May 23, 2005. https://www.webmd.com/sleep-disorders/muscle-relaxation-for-stress-insomnia
  6. D’Aurea, Carolina V.R., Dalva Poyares, Giselle S. Passos, Marcos G. Santana, Shawn D. Youngstedt, Altay A. Souza, Juliana Bicudo, Sergio Tufik, and Marco T. de Mello. 2019. “Effects of Resistance Exercise Training and Stretching on Chronic Insomnia.” Brazilian Journal of Psychiatry 41 (1): 51–57. https://doi.org/10.1590/1516-4446-2018-0030 
  7. Dr. Weil. 2014. “Video: Dr. Weil’s Breathing Exercises: 4-7-8 Breath.” DrWeil.com. June 26, 2014. https://www.drweil.com/videos-features/videos/breathing-exercises-4-7-8-breath/
  8. “Exercising for Better Sleep.” 2021. Www.hopkinsmedicine.org. August 8, 2021. https://www.hopkinsmedicine.org/health/wellness-and-prevention/exercising-for-better-sleep# 
  9. Farokhnezhad Afshar, Pouya, Fatemeh Bahramnezhad, Parvaneh Asgari, and Mahmoud Shiri. 2016. “Effect of White Noise on Sleep in Patients Admitted to a Coronary Care.” Journal of Caring Sciences 5 (2): 103–9. https://doi.org/10.15171/jcs.2016.011
  10. Gradisar, Michael, Amy R. Wolfson, Allison G. Harvey, Lauren Hale, Russell Rosenberg, and Charles A. Czeisler. 2013. “The Sleep and Technology Use of Americans: Findings from the National Sleep Foundation’s 2011 Sleep in America Poll.” Journal of Clinical Sleep Medicine 9 (12). https://doi.org/10.5664/jcsm.3272 
  11. Harding, Edward C., Nicholas P. Franks, and William Wisden. 2019. “The Temperature Dependence of Sleep.” Frontiers in Neuroscience 13 (April). https://doi.org/10.3389/fnins.2019.00336
  12. Hilditch, Cassie J., Stephanie A. Centofanti, Jillian Dorrian, and Siobhan Banks. 2016. “A 30-Minute, but Not a 10-Minute Nighttime Nap Is Associated with Sleep Inertia.” Sleep 39 (3): 675–85. https://doi.org/10.5665/sleep.5550 
  13. “Insomnia: Relaxation Techniques and Sleeping Habits.” 2017. Nih.gov. Institute for Quality and Efficiency in Health Care (IQWiG). March 9, 2017. https://www.ncbi.nlm.nih.gov/books/NBK279320/ 
  14. Krystal, Andrew D., Aric A. Prather, and Liza H. Ashbrook. 2019. “The Assessment and Management of Insomnia: An Update.” World Psychiatry 18 (3): 337–52. https://doi.org/10.1002/wps.20674 
  15. Messineo, Ludovico, Luigi Taranto-Montemurro, Scott A. Sands, Melania D. Oliveira Marques, Ali Azabarzin, and David Andrew Wellman. 2017. “Broadband Sound Administration Improves Sleep Onset Latency in Healthy Subjects in a Model of Transient Insomnia.” Frontiers in Neurology 8 (December). https://doi.org/10.3389/fneur.2017.00718
  16. “Michael Perlis, PhD | Behavioral Sleep Medicine Program | Perelman School of Medicine at the University of Pennsylvania.” n.d. Www.med.upenn.edu. Accessed July 28, 2023. https://www.med.upenn.edu/bsm/faculty_perlis.html 
  17. Mindfulness Matters. 2017. “Mindfulness Matters.” NIH News in Health. June 28, 2017. https://newsinhealth.nih.gov/2012/01/mindfulness-matters
  18. National Institute of General Medical Sciences. 2020. “Circadian Rhythms.” Www.nigms.nih.gov. National Institute of General Medical Sciences. 2020. https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx 
  19. Newsom, Rob. 2022. “Sleep & Job Performance: Can Sleep Deprivation Hurt Your Work?” Sleep Foundation. April 19, 2022. https://www.sleepfoundation.org/sleep-hygiene/good-sleep-and-job-performance 
  20. Park, Soon-Yeob, Mi-Kyeong Oh, Bum-Soon Lee, Haa-Gyoung Kim, Won-Joon Lee, Ji-Ho Lee, Jun-Tae Lim, and Jin-Young Kim. 2015. “The Effects of Alcohol on Quality of Sleep.” Korean Journal of Family Medicine 36 (6): 294. https://doi.org/10.4082/kjfm.2015.36.6.294
  21. Patel, Salma I., Bernie W. Miller, Heidi E. Kosiorek, James M. Parish, Philip J. Lyng, and Lois E. Krahn. 2017. “The Effect of Dogs on Human Sleep in the Home Sleep Environment.” Mayo Clinic Proceedings 92 (9): 1368–72. https://doi.org/10.1016/j.mayocp.2017.06.014 
  22. Reports, Consumer. 2016. “Why Americans Can’t Sleep.” Consumer Reports. January 14, 2016. https://www.consumerreports.org/sleep/why-americans-cant-sleep/
  23. Robinson, Kara Mayer. 2022. “Sleep Problems: Can Pink Noise Help?” WebMD. July 12, 2022. https://www.webmd.com/sleep-disorders/pink-noise-sleep
  24. Salamon, Maureen. 2020. “Blue Light and Sleep.” WebMD. October 3, 2020. https://www.webmd.com/sleep-disorders/sleep-blue-light
  25. Scullin, Michael K., Madison L. Krueger, Hannah K. Ballard, Natalya Pruett, and Donald L. Bliwise. 2018. “The Effects of Bedtime Writing on Difficulty Falling Asleep: A Polysomnographic Study Comparing To-Do Lists and Completed Activity Lists.” Journal of Experimental Psychology: General 147 (1): 139–46. https://doi.org/10.1037/xge0000374
  26. Silver, Natalie. 2019. “Best Temperature to Sleep: Research and Sleep Tips.” Healthline. December 13, 2019. https://www.healthline.com/health/sleep/best-temperature-to-sleep
  27. Skarpsno, Eivind Schjelderup, Paul Jarle Mork, Tom Ivar Lund Nilsen, and Andreas Holtermann. 2017. “Sleep Positions and Nocturnal Body Movements Based on Free-Living Accelerometer Recordings: Association with Demographics, Lifestyle, and Insomnia Symptoms.” Nature and Science of Sleep Volume 9 (November): 267–75. https://doi.org/10.2147/nss.s145777
  28. Staner, Luc. 2003. “Sleep and Anxiety Disorders.” Dialogues in Clinical Neuroscience 5 (3): 249–58. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181635/
  29. Suni, Eric. 2020. “Nightmares: Symptoms, Causes, & Treatment.” Sleep Foundation. October 9, 2020. https://www.sleepfoundation.org/nightmares
  30. Taylor, Paul. 2009. “Nap Time.” Pew Research Center’s Social & Demographic Trends Project. July 29, 2009. https://www.pewsocialtrends.org/2009/07/29/nap-time/ 
  31. Tordjman, Sylvie, Sylvie Chokron, Richard Delorme, Annaelle Charrier, Eric Bellissant, Nemat Jaafari, and Claire Fougerou. 2017. “Melatonin: Pharmacology, Functions and Therapeutic Benefits.” Current Neuropharmacology 15 (3): 434–43. https://doi.org/10.2174/1570159×14666161228122115
  32. Zwarensteyn, Jill. 2020. “Here Are the Effects of Sleeping in a Cold Room | Sleep Advisor.” The Sleep Advisor. January 2, 2020. https://www.sleepadvisor.org/sleeping-in-a-cold-room/