What are the Effects of Sleeping with the Lights On?

Some people prefer sleeping with the lights on because it offers a sense of security at night. Although it can keep Boogeyman away, turning on the lights at night can also affect your body’s internal clock and compromise the quality of your sleep. It can also increase your risk of developing sleep disorders. Is it better to sleep with the lights on? Let’s have a look at its pros and cons.

Benefits of Sleeping with the Lights On

There are only a few benefits of sleeping with the lights on. Here are some of its notable advantages, including alternative methods to help you wake up easily and feel a sense of security.

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— Helps You Wake Up Easily

Sleeping with the lights on may only be advantageous if you’re trying to take a nap and avoiding deep sleep. It increases your alertness, learning capacity, and memory. However, taking a nap with the lights on can still feel uncomfortable.

To help you wake up right away, setting an alarm is a must so you can stay within the recommended length without affecting the quality of your nap. Stick to 20 minutes or 90 minutes so you don’t wake up tired.

It’s also recommended to nap during the early afternoon to avoid messing up your sleep-wake cycle. Take an afternoon siesta between 1 PM and 3 PM.

— Sense of Security

There are many scientific explanations for why we feel afraid of the dark. From an evolutionary perspective, our ancestors were more exposed to predators, causing them to develop an innate fear of the dark.

As children, we felt safer sleeping with the lights on to avoid whatever kind of ghost we think is there. Some of us brought this habit into adulthood. We feel anxious that someone might break into our homes and put us to danger.

The best way to overcome a phobia of the dark is by facing your fear of it. Start with trying breathing techniques, reading any self-help book on getting over a phobia, then going to a therapist for cognitive behavioral therapy. You can also eliminate frightening sounds like fans and white noise so you can stay comfortable. Lastly, limit your exposure to violent or scary images.

— Safety

Going to sleep with the lights on can help children and the elderly navigate dark bedrooms and hallways in case they wake up. It avoids falling and tripping, especially when your kid’s room is full of toys, books, and other clutter.

If leaving the lights on is vital for your safety, pick a red or orange night light because it does not affect the circadian rhythm the same way white and blue light does. You may also try low-light bulbs.

Disadvantages of Sleeping with Lights On

Now, let’s discuss the significant downsides to sleeping with the lights on. These lights can inhibit your sleep and affect your health.

Affects Sleep Cycle

Human beings go through four to six cycles of sleep including rapid eye movement (REM) and non-REM. Each cycle lasts 1 to 2 hours. With light exposure during the evening, the transitions between each sleep cycle can be interrupted.

You are more likely to be awakened multiple times at night and the time you spend in deep, restorative sleep becomes shorter.

Increases Risk of Insomnia

An issue as minor as exposure to light at night can lead to a severe sleeping disorder like insomnia. Because your body is low in melatonin, you will wake up more often at night. Soon, these interruptions become more consistent and you will develop a pattern that leads to insomnia.

Keeping the lights dim two houses before sleeping helps you travel to dreamland easier. So if you want to be asleep by 10 PM, the overhead light should be off by 8 PM. Use warm colors like yellow and orange to prevent your internal clock from being affected.


You may develop migraine in two ways when you leave the light on. First, direct exposure to light can cause migraine because it activates the pathway from the eyes to your brain. Research even suggests that around 89% of 4000 participants with migraine are also more sensitive to light.

Another reason why exposure to light can cause migraine is the lack of sleep that comes with it. The disturbance of your sleep-wake cycle causes severe headaches throughout the day.

Hormonal Imbalance

Sleeping with the light on affects your hormones in many ways. First, it hinders the body’s melatonin production, a hormone that’s responsible for controlling your circadian rhythm. Melatonin Is produced in the pineal gland to regulate your sleep patterns. But low levels will prevent you from catching some Zs.

Your cortisol levels also spike when you’re sleep-deprived. This hormone, also known as the stress hormone, results in trouble falling asleep at night even though you are too tired.


Not getting enough sleep can also make you less alert. If you drive a car, your lack of alertness can lead to misfortune. You are also more susceptible to falls when you are sleep-deprived.

This is because lack of sleep can impair your cognition and affect your reflexes and reaction time. Your decision-making process becomes slower and you also tend to misjudge your choices.


A study shows that women who slept with a light or television on are more prone to obesity. They also have a high chance of gaining around 11 pounds in a year. The results only apply to leaving the lights on inside the room. Outside the room, turning on the light does not influence weight gain.

One reason behind this is their increased food intake due to lack of sleep. The less rest you get, the more you are likely to eat.

You may want to read: The Best Night Lights


In the end, it’s still your choice whether you want to sleep with the lights on or off. But it’s healthier to sleep in the dark or with a light that offers low illuminance. Turning off all devices and using blackout curtains can also let you doze off.

We hope this article taught you that darkness also matters! Would you rather sleep with a light turned on or off? Or do you use a nightlight? Share your sleeping experiences and questions with us in the comments below. And for more sleep health tips, check out our guide to the best sleep aids.

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