Evening use of computers might disrupt healthy sleep
The findings could be relevant also for those who use laptops and smartphones at night.
By JUDY SIEGEL-ITZKOVICH
If you’re having trouble getting to sleep at night, it may be due to using a tablet computer before your bedtime. A new study by Boston researchers just published in the journal Physiological Reports found that evening use of light-emitting tablet computers can induce delays in when a person wants to go to sleep, suppress secretion of melatonin (the hormone that regulates sleep and wakefulness) and impair next-morning alertness.Nine healthy adults participated in a randomized and counterbalanced study comparing five consecutive evenings of unrestricted use of light-emitting tablet computers versus evenings reading from printed materials.When the participants used light-emitting tablets in the evening, they self-selected bedtimes that were on average 30 minutes later; showed suppressed melatonin levels; experienced delayed timing of melatonin secretion onset; and had later sleep onset. When using the tablets, participants rated themselves as less sleepy in the evenings and less alert in the first hour after waking the following mornings.The findings could be relevant also for those who use laptops and smartphones at night.“These findings provide more evidence that light-emitting electronic devices have biological effects,” said co-author Dr. Jeanne Duffy of Brigham and Women’s Hospital and Harvard Medical School.“Using light-emitting electronic devices in the late evening can postpone our decision to go to sleep and make us more sleepy the next morning.”