Issue link: http://viewer.e-digitaleditions.com/i/57764
sheila I feature I Danger can hide in the most unassuming places. Forget radiation, this cuplrit is sinister screen time. There you lay, tucked up in bed, your partner breathing rhythmically beside you. Laptop perched upon bended knees, you focus on the day ahead – purchasing groceries ready for delivery to your door, paying bills, ordering school books, sending one more work email … before rewarding yourself with a quick browse on net-a-porter. By the time you close the lid and join your partner in the land of nod, you've clocked up some eight to 14 solid hours on a computer screen. Add to that the time you have spent sending and receiving text messages on your phone and browsing facebook on your tablet. It probably won't surprise you to know that research shows spending prolonged time on a backlit computer screen can play havoc with your health. And no, it doesn't end with eyestrain. Women of this generation are particularly hard hit. It's easy to see why when you consider that more women are active in the workforce than ever before and with electronic technology increasingly becoming an integral part of everyday life, there's less chance than ever before that the modern female can simply switch off t's late. Past pretty much everyone's bedtime. The house is in darkness … except, of course, for one pool of light in the bedroom. when she leaves the office. By the time she arrives home from work, prepares dinner, attends to some chores, it's likely she will pick up either a laptop, turn on a home computer, use a tablet or trawl the internet on her smart phone. Portable devices mean that when everyone else in the household has gone to sleep, it is entirely possible to continue working on screen in bed. The result, for many, is that when sleep finally is a priority, the body has trouble shutting down. The problem is that direct exposure to abnormal light sources inhibits the body's secretion of melatonin. Melatonin signals are sent through the brain in response to darkness, telling the body to prepare to shut down for the night. However, light-emitting devices such as phones, tablets and laptops, tell the brain to stay awake. Experts say the problem is worse for portable devices because users hold them close to the face and the effect is more marked than it is with something like a television or bedside lamp. The National Sleep Foundation in the US did a study last year which showed 95 per cent of people exposure to a backlit PROLONGED SCREEN PLAYS HAVOC who were not getting enough sleep were also using some kind of electronic device within an hour of going to bed. "Artificial light exposure between dusk and the time we go to bed at night suppresses release of the sleep-promoting hormone melatonin, enhances alertness and shifts circadian rhythms to a later hour – making it more difficult to fall asleep," says Charles Czeisler, PhD, MD, Harvard Medical School and Brigham and Women's Hospital. "This study reveals that light-emitting screens are in heavy use within the pivotal hour before sleep. Invasion of such alerting technologies into the bedroom may contribute to the high proportion of respondents who reported that they routinely get less sleep than they need." M looks at technologies that are passively received – such as TVs and music – versus those with interactive properties such as video games, telephony and internet access, which may affect the brain differently. "The hypothesis is that the latter devices are more alerting and disrupt ichael Gradisar, PhD at Flinders University, Australia, says his research SHEILA MARCH 2012 35