Here are six things that might be preventing you from feeling rested the next day—and what you can do instead to wake up more refreshed, according to Bicycling.

Your cell phone, iPad, and computer all emit blue light that messes with the hormone melatonin, which is responsible for regulating our sleep-wake cycles, according to Chris Winter, M.D., owner of Charlottesville Neurology and Sleep Medicine and author of The Sleep Solution: Why Your Sleep Is Broken and How To Fix It.

“Without melatonin, there’d be nothing to anchor our sleep to certain times,” he says. “We want that melatonin secretion right before we go to bed because it’s preparing us for sleep at night.” So when it’s dark outside and all the lights are off in your bedroom, your brain thinks you’re supposed to go to sleep. Putting a bright light right in front of your face has “the negative effect of your brain thinking that the sun is still out, so you should be awake.”