Can Blue Light from Phones Actually Affect Your Sleep?
It is often reported that smartphone screens emit blue light, which can interfere with your body’s production of melatonin—a hormone that regulates sleep-wake cycles. In theory, exposure to any light, but blue light in particular, before bedtime can delay sleep onset and reduce sleep quality by suppressing melatonin, a hormone key to the sleep-wake cycle.
However, the primary study often cited when claiming that blue light from a smartphone delays sleep onset involved subjects reading on a tablet at full brightness for four hours before attempting to sleep. This extreme scenario does not reflect typical phone use.
A more recent review study, published in Sleep Medicine Reviews in August 2024 looking at various studies over the past decade, found no conclusive evidence that the small amount of blue light emitted by a phone was enough to significantly impact the time it takes to fall asleep or overall sleep quality.
The study concluded that although the light emitted from devices may make a small difference to sleep onset time for some people, it is far less impactful than previously thought.
While phone screens are often blamed for sleep disruptions, overhead lighting in bedrooms may be playing a more significant role. Bright light from any source can suppress melatonin production, making it harder to fall asleep. Exposure to bright lights, especially in the hour leading up to bedtime, can trick the brain into thinking it’s still daytime, delaying the natural sleep cycle.
To create a more sleep-friendly environment, consider dimming overhead lights in the evening and using warm, soft lighting to signal to your body that it’s time to wind down. Installing dimmer switches or using bedside lamps with lower-wattage bulbs can also help reduce the impact of artificial lighting on sleep quality.
Dimming device screens or using night/eye-saver modes reduce blue light levels, further decreasing the chances that your night’s sleep will be affected by artificial light.
What You’re Viewing Might Matter More Than the Light
Engaging with smartphones before sleep can lead to psychological arousal, making it harder to fall asleep. Activities like reading emails, browsing social media, or playing games can stimulate the mind, delaying sleep onset and affecting sleep quality.
For example, viewing work-related emails or messages can trigger stress and anxiety, as these activities often require mental processing and problem-solving. This heightened state of alertness can prolong the time it takes to unwind and fall asleep.
Similarly, scrolling through social media can evoke emotional responses—whether excitement, frustration or worry—that further delay sleep onset. Interactive activities like gaming or online chatting can also keep the brain engaged, making relaxation before bed more difficult.
Any pre-sleep activity that is engaging might cause someone to lose track of time and remain awake beyond the intended bedtime. This is not exclusively an issue with technology, many people fall victim to a good book keeping them up for too long, but a key cornerstone of good sleep hygiene is consistent sleep and wake times.
Repeated delays in sleep onset can have significant negative effects on subsequent night’s sleep.
Rather than focusing solely on blue light exposure, it’s essential to consider the content you engage with on your phone. Opting for calming activities such as watching TV rather than replying to emails can help counteract these effects and support a smoother transition to sleep.
If I Dim the Lights and Read Calm Articles, Am I Safe?
Notifications and message alerts, even subtle ones, can be disruptive during the night. A simple buzz or vibration can pull you out of light sleep or keep you from fully relaxing at bedtime. This disruption is not just physical but psychological as well—work-related or emotionally charged messages can trigger stress and anxiety, making it harder to fall back asleep.
Over time, these disturbances can accumulate, leading to fragmented sleep patterns and leaving you feeling unrested and groggy in the morning.
One way to combat this issue is to enable “Do Not Disturb” mode or silence non-essential notifications during your sleep hours. Many smartphones allow you to customize these settings so that only critical alerts, like calls from close family members or emergencies, are permitted.
Additionally, consider placing your phone across the room or in a different location to avoid the temptation to check it when you wake up during the night. These small adjustments can help create a more restful and uninterrupted sleep environment.
Recommendations for Better Sleep Hygiene
If you’re worried about getting a good night’s sleep, it’s important to address both physical and psychological barriers that might be affecting your rest. For some people, removing technology from the bedroom can be useful but it’s not always practical or even necessary.
Technology in the bedroom should not disturb during the night, be used later than the intended bedtime or be used for mentally or emotionally engaging activities.
To improve sleep quality and reduce potential health risks, you might consider adopting the following strategies.
- Maintain a Consistent Sleep Schedule: Go to bed and wake up at the same time every day, even on weekends, to regulate your internal body clock.
- Limit Caffeine and Heavy Meals: Avoid caffeine and large meals in the hours leading up to bedtime, as these can disrupt your ability to fall asleep easily.
- Create a Relaxing Bedroom Environment: Ensure your bedroom is cool, quiet, and dark. Use blackout curtains, white noise machines, or earplugs if necessary.
- Incorporate Physical Activity: Regular exercise during the day can promote better sleep, but avoid vigorous activity close to bedtime.
- Avoid Napping Late in the Day: If you nap, try to keep it short and avoid doing so late in the afternoon, as it can interfere with nighttime sleep.
- Try Aromatherapy: Use calming scents like lavender to help relax your mind and body before bed.
- Engage in Relaxation Techniques: Practice mindfulness, deep breathing, or progressive muscle relaxation to reduce stress and prepare your body for rest.
- Minimise Alcohol Before Bed: While alcohol may make you feel sleepy initially, it can disrupt sleep quality later in the night.
- Establish a Pre-Sleep Routine: Engage in calming activities before bed, such as reading a physical book or practising relaxation techniques, to signal your body that it’s time to sleep.
- Adjust Lighting Levels: Dim overhead lights in the evening and use softer lighting options to create a calming atmosphere before bed.
By adopting these practices, you can create a healthier sleep environment and reduce the potential negative impacts of sleeping next to your phone.