Screen time and sleep: what the research actually shows

Adults in Tunis are sleeping, on average, 6.4 hours a night — nearly an hour short of the seven-to-nine hours the World Health Organization recommends. That gap is not random. Sleep researchers increasingly point to a single, familiar culprit sitting on every nightstand: the smartphone screen.

The timing matters. Hormone research published this year has reignited a wider conversation about how melatonin — the hormone that signals the brain to wind down — gets disrupted by artificial light exposure, particularly the short-wavelength blue light emitted by phones and tablets. That disruption pushes the body's internal clock later, compresses deep sleep, and leaves people groggy in the morning even after what felt like a full night in bed. In a city like Tunis, where the summer heat already pushes socialising well past 10 p.m. and cafés along Avenue Habib Bourguiba stay busy until midnight, late-night screen habits compound an already compressed sleep window.

What the research actually says

The core finding is not new, but the detail keeps sharpening. A 2023 meta-analysis published in the journal Sleep Medicine Reviews pooled data from 73 studies and found that each additional hour of evening screen use was associated with a 14-minute delay in sleep onset and a measurable reduction in REM sleep quality. For teenagers the effect was roughly double. The mechanism is straightforward: blue-light wavelengths between 450 and 490 nanometres suppress melatonin production by up to 85 percent for up to three hours after exposure stops.

The catch is that content matters as much as light. A person reading a static e-book emitting warm-toned light is in a meaningfully different position from someone scrolling short-video feeds at full brightness. The psychological arousal — the rapid-fire novelty stimulus, the social comparison, the unresolved notifications — keeps the stress hormone cortisol elevated independently of any light effect. Two people holding identical devices can have very different physiological outcomes depending entirely on what they are doing on them.

Researchers at the Institut Pasteur de Tunis, which has an active public-health education unit on the Rue du Colonel Hédi Chaker campus, have been tracking sleep quality data among working adults in the Grand Tunis region since 2024 as part of a broader non-communicable disease surveillance programme. Preliminary figures circulated at a March 2026 health symposium in La Marsa suggested that 58 percent of respondents reported difficulty falling asleep at least three nights a week, with late phone use cited as a contributing factor by more than half of that group.

What you can actually do about it

The advice that holds up to scrutiny is more specific than a blanket ban on phones. A hard stop 90 minutes before sleep is the most consistently supported intervention in the literature — long enough to allow melatonin levels to recover before the body needs to act on them. Activating a device's warm-colour night mode helps, but the evidence suggests the behavioural change matters more than the filter. Putting the phone in another room outperforms every software setting.

Several wellness practitioners operating out of the Menzah 6 district have started incorporating what they describe as a structured digital wind-down into client programmes — dimming lighting across all devices from 9 p.m., replacing social feeds with low-stimulation audio or print, and keeping the bedroom itself screen-free. The approach borrows from cognitive behavioural therapy for insomnia, known as CBT-I, which the European Sleep Research Society currently rates as the first-line treatment for chronic sleep difficulty ahead of medication.

The Tunis-based association Bien Dormir Tunisie, which runs monthly public workshops at the Centre Culturel International de Hammamet, began offering a free six-session sleep literacy programme in January 2026. Spaces in the October cohort are already filling. Registration is open through their online portal.

None of this requires abandoning your phone. It requires paying attention to when, and how, you use it in the two hours before bed. The science is consistent enough on that point that most sleep specialists consider it settled. The harder question is behavioural, not biological — and that is entirely within reach. Consult a local GP or sleep specialist if persistent sleep difficulties are affecting your daily function.