A claim you hear on longevity podcasts

Does screen time before bed hurt sleep?

The claim checked: Evening screen use can harm sleep for some people Hear it at 33:46

What do the studies say?

Strong consensus for

Nine of ten studies linked screen use, much of it in the evening or at bedtime, to shorter or worse sleep, and lab trials showed lower melatonin; most of the evidence is observational.

Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.

What was said on the podcast?

“So one of the reasons why screenius in the evening can for some people negatively impact their sleep is because it's working in complete opposition to what your body's circadian rhythm wants.”
Rangan Chatterjee · If Your Body Does THIS, Something Is Silently Draining Your Life & Energy · 33:46 on YouTube
The auto transcript writes "screenius" for "screen use".
Comes up in 3 episodes of the show.
Episode check Late caffeine hurts your sleep, the episode says. Ten studies split on it. 3 claims checked against 31 studies · 2 chapters not checked yet See the whole episode →
The point checked Strong consensus for

Evening screen use can harm sleep for some people

Agree 9

systematic review · 2015 · landmark

“Despite the above limitations, given the large number of studies with consistent findings, we report that there is a significant association between screen time and reduced sleep duration and increased sleep problems, across a range of screen types and sleep outcomes in 90% of the studies.”

Screen time and sleep among school-aged children and adolescents: a systematic literature review. Sleep Med Rev
Who: school-aged children and adolescents (primarily 5-17 years) across 67 studies worldwide
PMID 25193149

trial or observed group · 2015 · landmark

“This study demonstrates that use of a light-emitting electronic device in the hours before bedtime can have significant impact on sleep, alertness, and the circadian clock.”

Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proc Natl Acad Sci U S A
Who: Twelve healthy young adults (mean age 24.9 years, six women), inpatient randomized crossover
PMID 25535358

pooled analysis · 2016 · landmark

“Bedtime access and use of media devices was significantly associated with inadequate sleep quantity; poor sleep quality; and excessive daytime sleepiness.”

Association Between Portable Screen-Based Media Device Access or Use and Sleep Outcomes: A Systematic Review and Meta-analysis. JAMA Pediatr
Who: Children and adolescents aged 6-19 years (school age) in 20 cross-sectional studies; 125,198 children, 50.1% male
PMID 27802500

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other primary study · 2015 · landmark

“Extensive use of these devices was significantly and positively associated with SOL and sleep deficiency, with an inverse dose–response relationship between sleep duration and media use.”

Sleep and use of electronic devices in adolescence: results from a large population-based study. BMJ Open
Who: adolescents aged 16-19 in Hordaland County, Norway (youth@hordaland survey)
PMID 25643702

other primary study · 2016

“Exposure to a smartphone screen, particularly around bedtime, is associated with a lower quality of sleep.”

Direct Measurements of Smartphone Screen-Time: Relationships with Demographics and Sleep. PLoS One
Who: Adults (>=18 years) in the internet-based Health eHeart Study with Android smartphones; sleep analyses in subsets who completed the PSQI
PMID 27829040

pooled analysis · 2024

“In conclusion, our updated meta-analysis affirms the consistent negative impact of electronic media use on sleep outcomes, with problematic online gaming and smartphone use being particularly impactful.”

Electronic Media Use and Sleep Quality: Updated Systematic Review and Meta-Analysis. J Med Internet Res
Who: Children, adolescents and adults (study mean ages 9.9 to 65.6) in correlational studies from many countries; general and problematic use of smartphones, social media, online gaming and internet
PMID 38533835

controlled trial · 2018

“We found that unrestricted evening use of a LE‐tablet computer led to self‐selection of later bedtimes, and this was associated with suppression of the sleep‐promoting hormone melatonin, decreased evening sleepiness, delayed circadian rhythm timing, later sleep onset, and increased morning sleepiness compared to evenings with unrestricted use of only printed materials.”

Unrestricted evening use of light-emitting tablet computers delays self-selected bedtime and disrupts circadian timing and alertness. Physiol Rep
Who: 9 healthy young adults (6 men, 3 women), aged 25.7 ± 3.0 years, inpatient laboratory study
PMID 29845764

other primary study · 2023

“Low melanopic light shortens the time to fall asleep, attenuates evening melatonin suppression, reduces morning melatonin, advances evening melatonin onset and decreases alertness compared to high melanopic light.”

Melanopic irradiance defines the impact of evening display light on sleep latency, melatonin and alertness. Commun Biol
Who: 72 healthy males aged 18-35, in-lab
PMID 36854795

pooled analysis · 2020

“Toddlers' and preschoolers' evening screen time was unfavorably associated with sleep in 8/9 associations.”

Associations of screen time, sedentary time and physical activity with sleep in under 5s: A systematic review and meta-analysis. Sleep Med Rev
Who: Healthy children aged 0-4.99 years (infants, toddlers, preschoolers) in cross-sectional, longitudinal and experimental studies; 8 studies examined evening screen time
PMID 31778942

Partly agree 1

systematic review · 2018

“Another longitudinal study found cross-sectional associations between nighttime awakenings by the phone and sleep problems, perceived stress, and depressive symptoms in young adults, but no statistically significant prospective associations were seen at the one-year follow-up [ 269 ].”

Mobile Phone Use and Mental Health. A Review of the Research That Takes a Psychological Perspective on Exposure. Int J Environ Res Public Health
Who: Children, adolescents and adults (over 60% of adult studies in university students) in quantitative observational studies of mobile phone use
PMID 30501032

Disagree 0

None.

What else was said but not tested?

  • One reason is evening light exposure, which opposes the circadian rhythm and is alerting, making it harder to fall asleep
  • Other reasons: over-stimulation, stressful content, news

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