Have you ever wondered why scrolling on your phone at night can leave you tossing and turning for hours? You’re not alone. Experts have extensively studied the connection between our digital habits and sleep quality, and the findings are clear. This guide will decode the science behind how screen time affects your slumber.
When sleep experts discuss screen time, the conversation almost always begins with blue light. This isn’t just a buzzword; it’s a specific type of light that has a powerful effect on our brains.
All of our screens, from smartphones like the iPhone and Samsung Galaxy to laptops and TVs, emit high-energy visible (HEV) light, commonly known as blue light. During the day, exposure to blue light from the sun is beneficial. It boosts alertness, improves reaction times, and elevates mood. Your brain interprets this light as a signal that it’s daytime and you should be awake and active.
The problem arises at night. Your brain doesn’t distinguish between blue light from the sun and blue light from your phone. When you’re exposed to it after sunset, it sends a confusing signal that can disrupt your body’s natural sleep-wake cycle, known as the circadian rhythm.
Specifically, blue light suppresses the production of melatonin. Melatonin is a crucial hormone your brain’s pineal gland releases in response to darkness. It’s often called the “sleep hormone” because it signals to your body that it’s time to wind down and prepare for rest. According to research from institutions like Harvard Medical School, exposure to blue light at night can delay the release of melatonin and shift your circadian rhythm, making it harder to fall asleep and reducing the quality of the sleep you do get.
While blue light is a major physiological factor, experts also point to the psychological effects of our screen-based activities. The content we consume before bed plays a significant role in our ability to fall asleep.
Think about what you typically do on your phone at night. You might be:
Essentially, these activities keep your brain engaged and prevent it from entering the relaxed state necessary for sleep. Instead of winding down, your mind remains active, alert, and emotionally stimulated.
Another key point sleep specialists make is about what screen time displaces. Every minute you spend on a device before bed is a minute you are not doing something that could promote better sleep.
A healthy pre-sleep routine often involves calming activities that signal to your body and mind that the day is over. Screen time often replaces these beneficial habits. For example, instead of scrolling on a phone, you could be:
These activities help transition your body from the busyness of the day to a state of rest. By displacing them with screen time, we miss a critical window for relaxation.
Understanding the problem is the first step. The next is taking action. Based on expert recommendations, here are practical strategies to manage screen time and protect your sleep.
This is one of the most effective strategies. Designate a “screen-free” period of at least 60 to 90 minutes before your intended bedtime. Use this time for the relaxing, non-screen activities mentioned above. Set an alarm on your phone to remind you when it’s time to put it away for the night.
If you absolutely must use a device in the evening, make use of its built-in features to reduce blue light exposure.
Experts strongly advise keeping screens out of the bedroom. This strengthens the mental association between your bed and sleep, rather than work or entertainment. Charge your phone in another room, like the kitchen or living room, and use a traditional alarm clock to wake up.
If you use a device during your wind-down period, be mindful of the content. Instead of engaging in stimulating activities, use your device for something relaxing. Consider listening to a guided meditation on an app like Calm or Headspace, an audiobook, or a soothing podcast. The key is to choose passive, calming content over active, stimulating content.
What about e-readers like a Kindle? E-readers with e-ink screens that are not backlit, such as the basic Kindle or Kindle Paperwhite, are generally considered fine for bedtime reading. They don’t emit the same disruptive blue light as LCD screens on tablets and phones. However, be cautious with tablet-style e-readers (like an iPad with the Kindle app), as they use the same type of screen as a smartphone.
Is watching TV before bed just as bad as using a phone? While a TV also emits blue light, its effect can be slightly less potent than a phone’s for two reasons. First, it’s typically farther away from your face. Second, watching a show is often a more passive activity than actively scrolling and engaging with a phone. However, it still exposes you to blue light and potentially stimulating content, so it’s best to turn it off well before you plan to sleep.
Is it really just about the light? No. As discussed, the psychological stimulation from the content you consume is a major factor. Even with a blue light filter on, checking stressful work emails or getting into a debate on social media will still activate your brain and make it harder to fall asleep. The combination of both the physiological effect of light and the psychological effect of content is what makes nighttime screen use so disruptive to sleep.