e use of light-emitting electronic devices before bedtime may contribute to or exacerbate sleep problems. Exposure to blue-wavelength light in particular from these devices may affect sleep by suppressing melatonin and causing neurophysiologic arousal. We aimed to determine if wearing amber-tinted blue light-blocking lenses before bedtime improves sleep in individuals with insomnia. Fourteen individuals (n = 8 females; age ± SD 46.6 ± 11.5 y) with insomnia symptoms wore blue light-blocking amber lenses or clear placebo lenses in lightweight wraparound frames for 2 h immediately preceding bedtime for 7 consecutive nights in a randomized crossover trial (4-wk washout). Ambulatory sleep measures included the Pittsburgh Insomnia Rating Scale (PIRS) completed at the end of each intervention period, and daily post-sleep questionnaire and wrist-actigraphy. PIRS total scores, and Quality of Life, Distress, and Sleep Parameter subscales, were improved in amber vs. clear lenses condition (p-values <0.05). Reported wake-time was significantly delayed, and mean subjective total sleep time (TST), overall quality, and soundness of sleep were significantly higher (p-values <0.05) in amber vs. clear lenses condition over the 7-d intervention period. Actigraphic measures of TST only were significantly higher in amber vs. clear lenses condition (p = 0.035). Wearing amber vs. clear lenses for 2-h preceding bedtime for 1 week improved sleep in individuals with insomnia symptoms. These findings have health relevance given the broad use of light-emitting devices before bedtime and prevalence of insomnia. Amber lenses represent a safe, affordable, and easily implemented therapeutic intervention for insomnia symptoms.

The Sleep Foundation reports that exposure to blue light leading up to bedtime can hinder sleep. This is because: Group of answer choicesAll of the above are correctBlue light reduces the body temperatureBlue light may suppress the body's secretion of melatoninBlue light reduces heart rate

The Sleep Foundation names some common sources of blue light. These include: Group of answer choicesComputer screensLED lightsFluorescent lightsAll of the above

What do you do each night before closing your eyes? Do you use your phone to send messages, play games or even watch movies? You’re not alone. But did you know that the light from your screen can interfere with your sleep? If you are one of the millions of teenagers worldwide who are not getting a good night’s sleep, you may want to consider turning off your phone an hour before bed.Before the arrival of artificial lighting, we began and ended our day at the command of the sun. As sunlight diminishes, our bodies naturally produce a chemical called melatonin which helps to bring on sleep. But with artificial light, our brains can be fooled into thinking that night-time is actually daytime. The light from a phone’s screen is more problematic than other forms of artificial light because it has a higher concentration of blue light, the colour of light from the visible spectrum that most impedes melatonin production. This means that looking at a screen late at night can play havoc with your natural sleeping pattern, affecting the quality of your sleep, and making you feel tired in the morning even if you slept for a long time. Some phones have a special night-reading mode where white text is displayed on a black background. This helps to reduce the amount of blue light entering your eyes, but if you’re looking at the screen for a couple of hours, the purpose is defeated.Of course, screen time is not the only factor that affects your ability to sleep. For example, eating high-protein foods before bed can also affect how well you sleep. However, given that sleep is so important to your health, it may be time to evaluate your own mobile phone habits.Question promptWhy is blue light a problem at night?

Among the sleep disorders studied, insomnia demonstrated a more extensive association with indoor environmental factors, including light effect, temperature effect, and bed effect in men and temperature effect and bed effect in women, compared to other sleep disorders.

For people with delayed sleep phase disorder, light therapy is an option. When should people with DSPD get light exposure, if they want to bring forward their sleep-wake schedule?Group of answer choicesIn the two hours before bedtimeImmediately before bedtimeTwo hours after waking upImmediately on waking up