Screen Time and Sleep: What the Research Actually Shows

A new study from UCSF’s Weill Institute for Neurosciences is challenging some of the assumptions San Franciscans hold about late-night screen time and its impact on sleep. Published in the June issue of Sleep Medicine, the research tracked 2,200 Bay Area adults, comparing smartphone and tablet use after 8 p.m. against comprehensive sleep tracking over three months. The key result: people who used screens for longer periods after dark went to sleep an average of 37 minutes later than low- or no-device users, but reported only slightly lower sleep quality overall.

Device Habits on Both Sides of Market Street

The findings matter at a moment when insomnia complaints are spiking in San Francisco. According to the Department of Public Health, nearly 22% of city residents surveyed in 2025 reported difficulty falling asleep—up from 16% in 2018. The challenge is citywide, from Dogpatch software engineers troubleshooting code at 11 p.m. to the yoga crowds in Noe Valley scrolling meditation apps before bed. And with so many turning to devices for entertainment, meetings, and even calm-down routines, it’s not only adults: parents from Miraloma Elementary to Gateway Middle say they’re struggling to police screens in the evenings.

Sleep specialists at UCSF’s Osher Center for Integrative Health, just off Parnassus Avenue, see the smartphone-as-sleep-disruptor story play out daily. “A good third of our patients raise the topic on their own,” says a nurse practitioner there. Yet new perspectives are cropping up: therapists at The Sleep Center on California Street, and wellness consultants at Ritual Coffee’s Valencia Street location, increasingly focus on balancing screen time instead of eliminating it outright. Last month, the Inner Sunset’s Mindful Tech Project piloted a Friday night “Screen-Free Sleepover” to help local teens experiment with unplugging for just one night each month.

What the Science Really Measures

The evidence on blue light hasn’t shifted much: multiple studies still suggest that device screens emit enough short-wavelength light to temporarily suppress melatonin, the hormone that cues us to feel sleepy. But real-world research, including the UCSF study and a larger 2024 review in JAMA Pediatrics, suggests the story is about more than just biology. In the UCSF data, heavy evening users spent about $127 more annually on “sleep aids”—from chamomile teas to high-end blackout curtains—compared to light device users. Yet the number of sleep cycles per night among the two groups was almost identical (4.8 vs. 5.1, on average). Sleep timing shifts, but for many, device use doesn’t dramatically reduce total hours of rest.

Meanwhile, local tech companies are responding. Salesforce introduced a “Blue Hour” program this year for its Mission Bay campus, encouraging employees to put down screens after 9 p.m. and bill the company for in-person fitness, reading, or wellness activities one night a week. Fitness centers such as Dogpatch’s The Assembly have started “digital dusk” yoga classes, where attendees surrender their phones at the entrance—sessions typically book out days in advance.

Rethinking Tech and Rest—What’s Next in SF?

For city dwellers wrestling with their own phones at midnight, the advice is less about panicking over occasional scrolling, and more about patterns. UCSF’s public guidance now emphasizes consistency and routine: try to power down devices 30 minutes before your target sleep time, and, more importantly, keep a regular sleep and wake schedule even on weekends. For families, Glen Park’s Family Wellness Collaborative runs monthly workshops on screentime habits for kids, which have become so popular there’s now a waitlist for August and September.

Better sleep in San Francisco may not require going screen-free, but rather, getting smarter about when and how we use tech. For those looking to reset, Golden Gate Park’s early-morning running groups kick off just after sunrise, and countless local bookstores—from Green Apple to Booksmith—are seeing a bump in late-night shoppers looking for low-tech bedtime materials. For more serious, persistent trouble sleeping, doctors still recommend speaking with local sleep specialists. But for most, it’s about managing—not banning—the screens that have become part of city life.