Plenty of us sleep less as the price of making time for other things we feel matter more: Family time, work, a Thursday night outing, one more episode of Black Mirror. Plenty of us are aware that this choice probably isn’t the best for our long-term well-being, but some people tend to cope better with reduced sleep than others, which makes it easier to pretend you’ll be fine if you just drink Red Bull instead. The consensus? “When we get fewer than seven hours [of sleep], we’re impaired (to degrees that vary from person to person). When sleep persistently falls below six hours per 24, we are at an increased risk of health problems,” according to The Atlantic. But the number of hours you spend catching z’s isn’t the only factor that should be considered if you’re concerned about your sleeping habits: staring at your phone or other light-emitting devices actually does interfere with your physiological readiness to sleep, and all that coffee you’re drinking might make you more productive now, but you might want to think about cutting back a little for your New Year’s resolution. “Caffeine works primarily by blocking the action of a chemical called adenosine, which slows down our neural activity, allowing us to relax, rest, and sleep. By interfering with it, caffeine cuts the brake lines of the brain’s alertness system. Eventually, if we don’t allow our body to relax, the buzz turns to anxiety.”