A study published in Proceedings of the National Academy of Sciences reveals that light from tablets like the iPad impairs our ability to fall asleep and reduces sleep quality.
The culprit? Blue light.
Neuroscientist Anne-Marie Chang from Brigham and Women's Hospital in Boston, USA, demonstrates that screens on smartphones, laptops, tablets, and TVs harm sleep. This blue light from LEDs suppresses melatonin production—the hormone crucial for quality rest—by more than 50%.
Tablets throw off our internal clock.
Reading before bed: For two weeks, 12 participants read on a tablet for four hours on five consecutive evenings, then switched to a printed book the following week. They went to bed at 10 p.m. and woke at 6 a.m.
Results: Blood tests showed tablet readers took 10 extra minutes to fall asleep. They reported less immediate fatigue but experienced shorter sleep cycles overall.
Tablets suppress the sleep hormone.
Researchers observed over 50% less melatonin, disrupting our circadian rhythm. The next day, tablet users felt more fatigued than those reading print books, even after eight hours of sleep.
Shallower, less restorative sleep?
Tablet use delays sleep onset, leads to lighter sleep with micro-awakenings, daytime tiredness, and dozing.
Psychiatrist and sleep expert Sylvie Royant-Parola notes: "The effects are worse in complete darkness, as with smartphones used close to the eyes at bedtime, intensifying blue light exposure."
Practical tips.
Avoid blue-light devices before bed. Use apps like Twilight (Android) to filter blue light, gradually shifting to warmer tones at sunset and preserving your natural sleep cycle. iPhone users can apply screen films for similar protection.
Laura Girard
