Sleep consists of non-REM sleep (three progressively deeper stages) and REM sleep (rapid-eye-movement sleep associated with dreaming). Each stage helps restore the body and mind, allowing us to wake up feeling refreshed.
The Stages of Sleep (NREM 1–3 and REM)
Understanding sleep stages helps us appreciate their importance. A normal night’s sleep includes three NREM stages (N1, N2, N3) and REM sleep, each serving unique purposes:
Stage 1 (NREM1, Light Sleep)
This initial phase lasts about 1–7 minutes. Brain activity and muscle tension decrease, but you remain easy to awaken. Stage 1 doesn’t restore much on its own; it mainly prepares your body for deeper sleep.
Stage 2 (NREM2, Light Sleep)
Stage 2 is slightly deeper, lasting 10–25 minutes at first, then longer later in the night. Body temperature decreases, muscles relax further, and heart rate and breathing slow. Your brain creates brief bursts called “sleep spindles,” helping you stay asleep despite minor noises. Although not the deepest sleep, Stage 2 makes up about half your night’s sleep and helps memory and refreshment.
Stage 3 (NREM3, Deep Sleep)
Stage 3 is deep sleep, lasting about 20–40 minutes in early cycles. It’s the most restorative phase, characterized by slow delta brainwaves. Your body repairs tissues, builds muscle, strengthens immunity, and restores energy. Getting enough Stage 3 sleep also improves creativity, cognitive health, and memory.
REM Sleep (Rapid Eye Movement)
REM sleep is when dreaming usually occurs. The first REM period may last around 10 minutes but becomes longer in later cycles. Brain activity increases almost to waking levels, eyes move rapidly, and your body experiences temporary muscle paralysis to prevent dream enactment. REM sleep strengthens memory, emotional health, and creative thinking. Missing out on REM can harm memory and emotional stability.
Every sleep stage contributes to restorative sleep. Light sleep (Stages 1 and 2) guides us into deeper stages, Stage 3 rejuvenates the body, and REM rejuvenates the mind. Missing or cutting short any stage reduces sleep quality, leaving you feeling tired despite adequate sleep time.
How Smartphones Interfere with Sleep
Smartphones can negatively affect your sleep by disrupting natural sleep patterns and body rhythms. Here are the main issues:
Blue Light and Circadian Rhythm:
Smartphone screens emit blue light, which tricks the brain into thinking it’s daytime. This reduces melatonin (the sleep hormone), delaying sleepiness and shifting your internal clock later. This makes falling asleep more difficult, similar to experiencing jet lag.
Difficulty Falling Asleep and Reduced Deep Sleep:
Screen exposure before bedtime lengthens the time spent in Stage 1 (light sleep), reducing total sleep time in deeper restorative stages (Stage 3 and REM). Studies have shown nighttime screen usage reduces vital deep sleep, affecting cognitive functioning, immunity, and mood.
Mental Stimulation from Smartphone Content:
Engaging with stimulating content (emails, social media, games) keeps your brain active and alert when it should be calming down. This mental alertness delays sleep onset and reduces sleep quality.
Sleep Fragmentation from Alerts:
Notifications or the presence of a phone nearby can disrupt sleep by causing frequent awakenings, preventing continuous progression through sleep stages. This reduces overall sleep quality and leaves you less refreshed.
Shorter Sleep Duration and Insomnia Risk:
Frequent nighttime smartphone use leads to less sleep overall. A study found each hour spent on screens before bed increased insomnia risk significantly, reducing total sleep time and affecting REM sleep in particular.
Bottom line: Nighttime smartphone use delays sleep onset, reduces deep and REM sleep quality, and disrupts overall sleep patterns. Experts recommend keeping phones away from bedtime routines for better sleep.
How to Use Smartphones to Improve Sleep
While smartphones can disrupt sleep, smart use can actually improve sleep hygiene. Here are practical ways:
- Night Mode and Blue Light Filters:
Activate Night Mode to reduce blue light and melatonin suppression. Blue-light filtering glasses also help, but it’s still best to limit evening screen time. - Do Not Disturb and Bedtime Modes:
Silence notifications automatically during sleep hours to avoid disruptions. Bedtime modes further reduce screen distractions. - Relaxation and Meditation Apps:
Apps like Calm or Headspace offer guided meditations, helping you relax and sleep better. Use these apps audio-only to avoid screen exposure. - White Noise Apps:
Soothing ambient sounds or white noise apps mask disruptive noises, promoting deeper sleep. - Sleep Tracking and Smart Alarms:
Sleep apps raise awareness about sleep habits and gently wake you during lighter sleep stages, reducing morning grogginess. - Routine Reminders:
Set alarms to remind you to wind down, enforce good sleep habits, and create consistent bedtime routines.
Smartphones, when used wisely, can enhance sleep quality through helpful features, relaxation techniques, and mindful sleep tracking.
Smartphone Usage Tips by Age Group
Different ages have unique sleep challenges. Tailor smartphone habits accordingly:
Children (up to 12 years):
- Stop screen use at least 1 hour before bedtime.
- Keep phones/tablets out of bedrooms overnight.
- Use parental controls, Night Mode, and consistent sleep schedules.
Teens (13–18 years):
- Discuss phone use boundaries and establish nightly screen-free time.
- Keep phones outside bedrooms or in Do Not Disturb mode overnight.
- Avoid emotionally charged or stimulating content late at night.
Adults (19–64 years):
- Set strict bedtime limits for phone use.
- Avoid work emails and stressful content at night.
- Keep bedroom device-free or only use calming apps.
Seniors (65+ years):
- Avoid screens at least an hour before bedtime.
- Use Night Mode and reduce screen brightness.
- Limit nighttime phone checks to minimize sleep disruption.
Good sleep hygiene at any age includes mindful smartphone use, prioritizing restful sleep, and creating a calm bedtime environment.
Conclusion: Balancing Smartphones and Healthy Sleep
Smartphones impact sleep significantly, but how we use them determines the outcome. Avoid harmful habits like bedtime scrolling, and instead use helpful tools and apps to enhance your sleep. Be mindful of how smartphone use affects your sleep quality, and make intentional choices to improve rest and health at every age.
Remember: Prioritize sleep over your smartphone, especially at night. Your sleep—and overall health—will thank you. Sweet dreams, and don’t forget to power down for a good night’s sleep!