The human body takes its cues for energy and wakefulness from the sun.
Sunlight influences the circadian rhythms, so we feel more alert and awake during daylight hours and sleepier when the night falls. Ergo, a dark room will always aid rest.
For some people, sleeping in a dark room is a simple matter of psychology. No matter how tired you are during the day, you’ll find it impossible to rest while sunlight streams through the bedroom window.
Keeping your bedroom dark also enhances sleep onset, as darkness encourages the brain to produce melatonin – the “sleep hormone” – and makes sleeping for 8 hours likelier.
Turning out the lights means you’ll burn more calories at rest, protect your eyes from damage, and improve insulin resistance to fight diabetes. A dark bedroom at night also combats depression.
If you can’t sleep without a light on, potentially due to nyctophobia (fear of the dark) or prolonged exposure to light pollution, work to improve your sleep hygiene and break this habit.
Is Sleeping in a Dark Room Better for You?
Sleep experts worldwide recommend that we sleep in complete darkness. This routine is ingrained in most of us since childhood and continues throughout our lives.
Sleeping in pitch darkness isn’t a habit we fail to grow out of. There are many benefits to ensuring your bedroom is dark before you draw your day to a close:
Psychology
Circadian rhythms primarily impact the body, but they also influence the mind. For many people, psychology plays a part in the desire to sleep in darkness. Sleeping during daylight feels wrong.
If you want an early night, perhaps because you slept poorly the day before or have been traveling and are tired, be realistic about when you can fall asleep.
The brain may rebel against the body’s desire to sleep if it’s still light outside.
You can bring darkness into your bedroom through artificial means, including shielding your eyes and drawing curtains, but it may take a while for the brain to accept this and allow itself to be tricked.
Easier To Fall Asleep
Perhaps the most significant advantage of sleeping in a dark room is that you’ll be able to sleep much faster. As discussed, circadian rhythms in the body are guided by natural light.
When this light dims and disappears, the brain releases the hormone melatonin.
Melatonin isn’t a direct sedative and won’t put you to sleep regardless of your environment. Melatonin encourages the muscles and brain to relax, which can lead to feelings of drowsiness.
Melatonin production and release can quickly be reversed and blocked by light, which is why it’s so important to keep your bedroom as dark as possible.
Start the melatonin release process by dimming lights throughout the evening and adjusting to darkness.
Sleep Quality
We’ve established that you’ll sleep easier in darkness, but does a darker room improve sleep quality?
Resting in a dark room, especially if the bedroom is also chilled to an appropriate temperature, can help you remain asleep for multiple sleep cycles instead of being wrenched from sleep unexpectedly.
You’ll likely be woken if somebody flips a light switch while sleeping.
Your body will acknowledge the arrival of light, and your circadian rhythms will reset, convincing you it’s time to wake up. It may then take some time to doze off again.
Artificial light sources also diminish the length and quality of your sleep.
Somnologie explains how lamps and overhead lights cause circadian rhythm sleep-wake disorders (CRSWD), which confuse the body as to whether it should sleep deeply or just nap.
Physical Health
Sleeping in a dark room will also improve your health, partly due to higher quality rest. The more time you spend in slow-wave sleep, the greater opportunity your body will have to heal and repair itself.
Eye health is the first concern that sleeping in darkness can alleviate. While many children and some adults prefer to sleep with a night light, the BMJ warns that this can damage vision.
Turning out the lights while you sleep allows your eyes to rest and recuperate after a day of exposure to brightness, especially if you work with screens or frequently use them for recreation.
Sleeping in darkness can also have a positive impact on your weight. The human body burns calories during sleep, but JAMA International Medicine warns that illumination can slow this process down.
You’ll still need to watch your diet to control your waistline. Sleeping in darkness alone isn’t equivalent to a crash diet, but you’re likelier to avoid weight gain while sleeping.
You may even find that sleeping in a dark room improves your skin and helps you look younger over time. The cells in the skin regenerate much faster when not exposed to prolonged light.
Mental Health
Sleeping in darkness can also improve mental health, lifting mood and improving cognitive function.
As a dark room will encourage you to sleep through the night, you’ll enjoy superior memory and decision-making skills upon waking.
The American Journal of Epidemiology also connects sleeping in an illuminated room with depression.
A study found that participants subjected to even low light levels in a bedroom led to depressive symptoms, even if they weren’t present before.
Insomnia and broken sleep are also frequently linked to low mood, irritability, and anxiety.
By keeping the lights out in your bedroom and sleeping well through the night, you’re likelier to wake up in a better frame of mind.
How Dark Should Your Room Be To Sleep?
Allowing the body to embrace its circadian rhythms fully, your bedroom should only contain natural light during sleep. If you live in an area with a lengthy summer and the sun doesn’t set beyond bedtime, some illumination will be inevitable.
You can probably work around this and prevent light from disrupting your sleep. but don’t allow additional brightness to enter your sleep.
As well as turning off all the lights in a bedroom, take the following steps:
- Prepare yourself for darkness by dimming all lights in the home as the night progresses.
- Draw curtains and blinds, as long as you can be trusted to wake in the morning without the sun acting as an alarm clock.
- Wear an eye mask to block light if necessary.
The darker your bedroom is, the more melatonin your brain will produce, and the better you’ll sleep.
Why Can’t I Sleep Without a Light On?
If you find it impossible to sleep without a light or lamp on, here are the explanations:
- You have nyctophobia, or fear of the dark, and struggle with feelings of anxiety in darkness.
- Your bedroom is subject to light pollution from outside the house, such as bright streetlights, which creates an expectation of sleeping with some illumination.
- You’re using screens late into the night, whether a TV, computer, laptop, or cellphone, and your eyes continue to expect to be exposed to light.
These concerns can be managed, though nyctophobia will be the biggest challenge.
Light pollution can be managed by changing your sleep habits. Get blackout blinds or wear an eye mask periodically during the day until you create a psychological association between sleep and darkness.
A reliable sleep hygiene routine is at the heart of breaking a reliance on the blue light emitted by screens. Avoid using technology for at least 1 hour before bed, and retire at a set time each night.
Side Effects of Sleeping with Lights On
Sleeping with the lights on may alleviate feelings of anxiety or unease you experience in darkness, but there are long-term repercussions to illuminating your bedroom at night.
Keeping the lights on can lead to weight gain overnight – or, at the very least, reduced weight loss – alongside an enhanced risk of diabetes and myopia.
Proceedings of the National Academy of Science also warn that keeping the lights on at night can increase your heart rate and blood pressure. This can lead to cardiovascular issues later in life.
If overweight or otherwise at risk of developing diabetes, sleep in pitch darkness. Dozing in illuminated conditions has been shown to increase resistance to insulin the following day, which can harm our health.
If your muscles and organs struggle to manage glucose in your blood, the pancreas will release more insulin to manage the process.
Constantly feeling thirsty and hungry, nocturia (peeing at night), headaches and blurred vision, and slow responses to minor cuts and abrasions are all warning signs of pre-diabetes.
If you need exposure to light overnight, turn out the lamps and overhead illumination in your bedroom, open your door, and leave on a hallway light.
Sleep scientists recommend sleeping in complete darkness with a reduced temperature.
