It’s 4 o’clock, you can barely keep your eyes open, and you’ve got a tough decision to make. Should you ride out the exhaustion (and possibly face plant at your desk)? Or should you perk yourself up with a cup of coffee—and potentially put the good night’s sleep ahead of you in peril?
It’s a real tradeoff, and it’s hard to know if it’s one worth making. Here’s what to know about how late you can drink coffee without sacrificing sleep.