How screens are reshaping sleep health

Digital habits are disrupting sleep across Europe, especially among adolescents. Why this matters for stress, cognition, and long-term health.

Digital devices and the new landscape of sleep disruption

The past decade has seen an unprecedented rise in sleep complaints across Europe, with adolescents and adults reporting shorter nights, more fragmented rest and a persistent sense of fatigue. While multiple factors contribute to this trend, the use of digital devices in the evening hours has emerged as one of the most pervasive and clinically relevant. Smartphones, tablets and gaming consoles have become the final stimulus before sleep for millions of people, subtly but consistently shifting circadian rhythms, increasing physiological arousal and undermining the restorative value of sleep.

The epidemiological signal is clear: young Europeans are sleeping less than ever. Surveys from Northern and Western Europe show a decline of 30 to 60 minutes in average sleep duration over the past 15 years, with marked differences between countries but a homogenous downward trend. Among adolescents, up to one-third now falls below the recommended 8–10 hours of sleep on school nights, a proportion strongly associated with increased screen exposure. Hale and Guan’s review demonstrated that screen media use is consistently linked to delayed bedtimes, prolonged sleep latency and reduced total sleep time in youth.

But the phenomenon no longer belongs to adolescents alone; adults now display similar patterns, influenced by late-night messaging, work-related notifications and the habit of scrolling through news or social media before bed.

Digital overstimulation and the biology of poor sleep

The biological mechanisms underlying this shift are well-characterised. Exposure to short-wavelength (“blue”) light suppresses melatonin secretion, delaying the onset of sleep and shifting the internal circadian clock. Controlled laboratory studies, such as the work by Höhn and colleagues, have shown that even brief evening use of a smartphone can reduce endogenous melatonin and impair the depth of subsequent sleep, with measurable consequences on cognitive performance the next morning.

But the disruptive effect of digital devices extends beyond light itself. Interactive content increases sympathetic activation, emotional arousal and cognitive load, particularly when the activity involves social interaction or competitive gaming. This “alerting effect” contrasts sharply with the physiological winding-down process required for healthy sleep initiation.

Adolescents represent a uniquely vulnerable group

Their circadian system is naturally shifted toward later phases, and evening exposure to screens amplifies this delay, making early school start times even more misaligned with biological rhythms. Studies in the UK, Germany and the Nordic countries have linked nighttime device use with poorer academic performance, mood instability, irritability and higher rates of daytime sleepiness.

Lemola’s longitudinal research went further, showing that nighttime electronic media use is a significant predictor not only of sleep disturbance but also of depressive symptoms, an association likely mediated by a combination of sleep reduction, social stress and emotional overstimulation. The effects accumulate over time, contributing to a cycle in which insufficient sleep worsens self-regulation and increases the likelihood of further late-night device engagement.

Adults, too, are far from spared

Evening digital exposure is common among shift workers and healthcare professionals, whose schedules are already prone to circadian disruption. Notifications arriving during on-call periods, messaging between colleagues and the widespread expectation of after-hours responsiveness keep the sympathetic system activated late into the night. Over time, chronic sleep restriction contributes to higher stress levels, reduced resilience, impaired glucose metabolism and increased susceptibility to infections. For clinicians, this pattern has tangible implications: poorer sleep is associated with slower reaction times, diminished concentration and a higher likelihood of errors.

Beyond individual behaviour, the issue reflects a broader shift in the modern sensory environment. Digital devices occupy the final cognitive space before sleep, replacing activities that historically facilitated relaxation - reading, low-stimulus routines, quiet social interaction. The transition from wakefulness to rest becomes compressed, and the brain receives fewer cues to disengage. Even interventions designed to mitigate harm, such as “night mode” or blue-light filters, provide only partial benefit. Trials in university students have shown modest improvements in subjective sleep quality when blue light is reduced, but these measures do not fully counteract the cognitive and emotional stimulation inherent to interactive devices.

Clinically, this poses several challenges but also opportunities. Traditional sleep hygiene advice remains necessary but insufficient when patients face constant digital stimuli. Instead, evidence increasingly supports the need for structured behavioural interventions, such as cognitive behavioural therapy for insomnia (CBT-I), which addresses pre-sleep arousal, conditioned wakefulness and the cognitive loops that delay sleep. For adolescents, delaying school start times where feasible, establishing protected “digital curfews” and involving caregivers in managing device use may reduce the chronic misalignment that fuels fatigue and emotional dysregulation. For adults, especially healthcare workers, organisational strategies that limit after-hours digital demands and support predictable rest periods may prove more impactful than individual-level recommendations alone.

Europe grapples with rising stress levels

As Europe grapples with rising stress levels, mental health concerns and a persistent decline in sleep duration, it is increasingly clear that sleep health must become a central component of preventive medicine. Digital devices are not the only determinant of sleep disruption, but they represent one of the most ubiquitous and modifiable. Recognising their impact allows clinicians to move beyond generic advice and toward targeted interventions that address the pathways through which the digital environment infiltrates and fragments rest.

Sleep is not merely the absence of wakefulness; it is an active, restorative process essential for physical, emotional and cognitive resilience. In the digital era, protecting it requires both individual awareness and systemic change.

Sources
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  4. Arshad D, Joyia UM, Fatima S, Khalid N, Rishi AI, Rahim NUA, Bukhari SF, Shairwani GK, Salmaan A. The adverse impact of excessive smartphone screen-time on sleep quality among young adults: A prospective cohort. Sleep Sci. 2021 Jan-Mar;14(4):337-341. doi: 10.5935/1984-0063.20200114. PMID: 35087630; PMCID: PMC8776263.