“Our circadian rhythms, or sleep cycle, require consistency,” explains board-certified sleep specialist Michael Breus, PhD, author of Good Night: The Sleep Doctors 4-week Program to Better Sleep and Better Health. “Anytime you try to sneak an extra snooze or get an artificial boost, you’ll find yourself physically tired but mentally wired when trying to get to bed, and then drowsy again the very next day—it’s a vicious circle.” Messing with those rhythms will wreak havoc with a host of bodily functions including hormone release, body temperature, weight control, and even immunity, not to mention that it will zap your energy, mood, memory, and powers of concentration. Here, the 8 worst moves you can make when you’re sleepy.

  1. Taking a nap Unless you’re about to get behind the wheel or perform brain surgery, pass on the mid-day snooze, tempting as it may be. “Napping will ultimately lower your sleep drive,” Breus explains, which is the body’s desire to sleep. With a lowered sleep drive, you’re more likely to stay up later, leaving you zombie-fied the next day. If you literally can’t keep your eyes open and absolutely must sneak in some shut-eye, the best window is between 1 pm and 3 pm, early enough that the afternoon snooze won’t keep you awake when it’s time to turn in for the night. And limit the nap to 25 minutes to prevent falling into a deeper stage of sleep that will leave you groggy when you wake and dramatically impact your ability to get to sleep at night.
  2. Turning in early When you’re totally exhausted, it’s tempting to revive your third-grade bedtime, but that’s likely to desynchronize your circadian rhythm over time. “Your brain is not ready to fall sleep early, so you will get in bed, exhausted, and what I call ‘wired and tired’—body tired and brain on,” Breus says. “This usually just leads to frustration when you can’t fall asleep, which makes it even more difficult to nod off.”
  3. Sucking down extra coffee Depending on your personal tolerance to caffeine, it may be fine to sip coffee or other caffeinated drinks until 2 pm. The average half-life of caffeine is 8 to 10 hours (meaning the time it takes for half of the caffeine to work its way out of your system), so you should be fine to go to bed at 10:30 pm. But too much of a jolt (over 200 mg, roughly the amount you’d get from two cups of coffee or one Monster energy drink), especially after about 2 pm, can sabotage your sleep quality. “You might drift off easily enough, but the caffeine in your system will keep you in the lighter stages of sleep,” Breus says, so you won’t feel as rested or refreshed when you wake up. MORE: The Amount Of Caffeine In 29 Of Your Favorite Foods And Drinks
  4. Sleeping in Ah, weekends. No work, no alarm, just sweet slumber til your eyes gently flutter open. Sorry to burst your idyllic Saturday morning bubble, but this is a bad idea. “Your sleep clock will readjust after just one morning of sleeping in,” Breus explains. “Even just 30 minutes over a two-day span could cause a shift, prompting your body to want to sleep later and get up later.” Translation: Monday morning will be way more painful than usual.
  5. Having a nightcap Some pre-bedtime booze may feel like a sedative, but you won’t sleep as deeply, especially during the second half of the night, and you might even wake up once the alcohol is fully metabolized. A 2013 review of 27 studies found that alcohol reduces rapid eye movement (REM) sleep, the part of the cycle considered to be the most mentally restorative. Studies also show that REM sleep is when we move information from short-term to long-term memory. A drink with dinner is fine, just be sure to empty your glass a good three hours before turning in.
  6. Soothing with social media Your lids are drooping but you’ll just check Facebook one more time, right? Wrong. Besides the fact that you’ll probably fall down a social media rabbit hole, which may be more likely when you’re sleepy and fresh out of self-control, research shows that the short, blue wavelength light emanating from your screen mimics daylight, throwing off your circadian rhythm. “The light from your laptop, tablet, or phone can have an effect,” Breus says, “but even worse is the engagement of social media at night. It really amps up the brain, making it tough to fall asleep.” And the more brainpower you use, the more alert you will become. “If you’re chatting back and forth with friends, that’s a higher level of cognitive engagement than if you’re passively watching a video,” Breus says.
  7. Doing Asanas True, yoga poses can relax you—unless you do the wrong ones. “Yoga is meant to be relaxing but also energizing,” Breus says, “especially inversions, or poses where your head is below your heart.” The safest bets are corpse pose, child’s pose, and other still postures that won’t increase your heart rate. Hold each pose for 10 to 30 gentle breaths for maximum zen. (Try these 3 yoga poses to help you sleep.)
  8. Eating a midnight snack We don’t always make the wisest food choices when we’re tired (hello, leftover Chinese food!), and feasting on food that leaves you feeling heavy means you could spend the next few hours counting sheep. “The body was not meant to digest food lying down,” Breus says. “In many cases eating late, or eating foods that are spicy or hard to digest—like hamburgers, because of the high protein—can cause silent reflux, a type of heartburn that you may not even realize you have.” It makes it hard to go to sleep and causes damage that you’re unaware of. Going to bed hungry could also keep you awake, so if you must snack before sleep, choose a 250-calorie nibble that’s 80% carbs and 20% protein, a combo shown by research to have a calming effect. Try cheese and crackers, Greek yogurt with bananas, or pairing almond milk and low-sugar cereal. To avoid getting sleep deprived in the first place, your best bet is to follow the old “sleep hygiene” advice you’ve no doubt heard a million times and have been choosing to ignore: Go to sleep and wake up around the same times each day (within 15 to 20 minutes is fine) and create a grown-up version of the bedtime routine that works so well with kids. About an hour before hitting the sheets, shut off your devices, close down the kitchen, and do things you find soothing—reading, meditating, listening to music, etc. Make sure your bedroom is dark and on the cool side (68 to 72°, if possible), so you can sleep deeply and feel rested the next day. MORE: 12 Ways To Look Like You Got A Great Night’s Sleep