In case you've been living under a rock for the past 20 years (and if so, you're probably well rested, so this wouldn't apply to you), Americans need more sleep. Seven to nine hours is the sweet spot for waking up refreshed, and as anyone who has pulled a late-nighter with her Netflix queue knows, getting less than that can leave you groggy, cranky, and way worse. Just one night of insufficient shut-eye can slow your job performance, derail your gym routine, and even sabotage your relationships, new research shows. But worry not, weary eyes. We've pinpointed exactly what suffers when you're sleepy and how to sidestep those problems and feel wide awake.
One bad night's sleep reduces the body's ability to process sugar the next day and leads to greater fat storage, a study in the Journal of Clinical Endocrinology & Metabolism found. According to Amy Jamieson-Petonic, RD, a spokeswoman for the Academy of Nutrition and Dietetics, you can thank a triple threat of hormones that go haywire with too little slumber: ghrelin, which makes you crave fatty and sugary foods; leptin, which regulates how much you eat; and cortisol, which tells your body to hold on to visceral fatty tissue around the abdominals.
Wake-up call: As tempting as it may be to reach for a bacon, egg, and cheese sandwich or a chocolate-chip muffin, giving in to cravings can backfire. Fatty foods require a lot of energy to digest, leaving you even more sluggish, and sweet treats and processed carbohydrates cause your blood sugar and energy levels to spike and crash. "Counter the bulge by choosing foods that keep blood sugar steady throughout the day for lasting energy," Jamieson-Petonic says. A mix of complex carbs and protein is your best bet: oatmeal and an apple for breakfast, grilled chicken on whole wheat bread with a salad for lunch, a banana with two tablespoons of peanut butter as a snack, and salmon with brown rice and veggies for dinner.
Your morning run or Spinning class is also great for middle management: Not only does exercise help reduce cravings, but it also moves excess sugar from your bloodstream to your muscles instead of converting it to fat and storing it in your fat cells, according to Michele S. Olson, PhD, a FITNESS advisory board member and professor of exercise science. So if you do sneak those chips, they're less likely to end up on your hips.
Your Exercise Routine
A restless night may make you hit "Snooze" on your workouts. Men and women who slept poorly were 57 percent less likely to exercise the following day, a recent survey by the National Sleep Foundation found. A few wakeful nights strung together can seriously spiral. "Because exercise helps you sleep better, letting your gym routine slide until you're less sleepy will make it more difficult to fall asleep, setting you up for a vicious cycle," says Shawn Youngstedt, PhD, an associate professor of exercise science at the University of South Carolina in Columbia.
Wake-up call: Even if you're dragging, it's crucial to do something. "Tell yourself that you'll work out for 15 minutes," Youngstedt says. "Studies show that once people start exercising, they want to continue and often feel more energized when they're done." In fact, adults who did 20 minutes of low-intensity bike riding experienced a 65 percent decrease in fatigue, according to a study from the University of Georgia. An earlier review from the same research team found that exercise had a more powerful effect on a person's level of energy than stimulant drugs did.
But moderation is key. Exercising too hard can make you more tired and increase your risk of injury, because fatigue can hamper concentration and form. "When you're feeling sleepy, back off a little from your workout status quo; reduce the intensity and duration of your exercise," Youngstedt suggests. And toss the old idea that working out before bed makes it harder to fall asleep: People who exercise, no matter the time of day, sleep better than those who don't exercise at all, according to the same National Sleep Foundation survey.
Related: 5 Gadgets to Get More Sleep
Ever notice how days seem to drag when you're most tired? Sleep-deprived people take longer to complete routine tasks and are less productive than those who sleep soundly, according to a study in the Journal of Vision. (Only anecdotal evidence suggests that it takes the clock longer to reach 5:00 p.m. when you're zonked.) "A bad night's sleep wreaks havoc on the prefrontal cortex, the part of your brain responsible for creativity and innovation," explains Christopher Barnes, PhD, a sleep and ethics researcher at the University of Washington in Seattle. "When you're sleeping, those brain cells regenerate, so you function optimally the next day. When you cut that process short, performance suffers."
Wake-up call: Napping, even for 10 to 20 minutes in your car on your lunch break, is the best way to mitigate the effects of a poor night's sleep and help you regain focus, Barnes says. If you don't drive to work (and falling asleep in the bathroom stall isn't an option), the next best thing is to organize your day around your body's circadian rhythms. Schedule creative projects and tasks that require brainstorming for the morning, when you tend to be most alert. Tackle routine to-dos -- the ones you can do in your, um, sleep -- at 3:00 p.m., when your energy nosedives.
Coffee also helps, because caffeine can boost concentration and mental alertness, according to a study in the Indian Journal of Social Science Researchers. Plan your java fix for when you need the most brainpower. Coffee's effect is strongest 30 minutes to three hours after your first cup. Be careful not to drink it too late in the day because lingering effects of caffeine could prevent you from nodding off at night, says Jeffrey Mechanick, MD, an endocrinologist at the Icahn School of Medicine at Mount Sinai in New York City. Big meeting at 4:00? Take a 10-minute walk directly beforehand to get the blood flowing and bring oxygen to your brain, says Joyce Walsleben, PhD, a professor of sleep medicine at New York University. Fog lifted!
Lack of sleep can turn you into a serious Medusa. Without sufficient shut-eye, brain chemicals like serotonin don't have time to replenish, making you irritable and moody, Walsleben says. It's no surprise, then, that sleep-deprived couples have a tough time valuing and expressing appreciation for their significant other the next day, according to a recent study from the University of California, Berkeley. "When people feel taken for granted, it makes them angry and unwilling to give," says Mira Kirshenbaum, PhD, a relationship therapist and the author of I Love You, But I Don't Trust You. "That can build resentment in an otherwise loving relationship."
Wake-up call: You can't control brain chemicals, but you can quash the tendency to point out the negative, Kirshenbaum says. Make it your goal to notice thoughtful gestures when you're short on sleep, like whether he brought you coffee or called to wish you luck before a big meeting. The more you focus on the positive, the more you'll find, and the more you'll value your partner, she says. On mornings when you're both tired, play a game to see who can be most thoughtful. It sounds silly, but the point is to make you both less cranky and more caring. Last, the day after a bad night's sleep is not the time to have difficult discussions or talk about feelings or grievances, Kirshenbaum says. Catch some zzz's, then tackle the tough stuff.
When you're groggy, so is the imaginary angel on your shoulder, and the devil gets full rein. The prefrontal cortex of the brain that regulates self-control (and tells you not to friend your ex on Facebook or have one more drink) gets thrown out of whack, Barnes says. The result: Those who are sleep deprived are more likely to have less self-control, take greater risks, and focus on the reward rather than the danger.
Wake-up call: Take a walk and think it over. Ten to 40 minutes of physical activity improve self-control and reinforce inhibition, according to a study published in the British Journal of Sports Medicine. Researchers speculate that exercise increases blood and oxygen flow to the prefrontal areas of the brain, snapping you back to your normal-thinking self. Or try this trick that fosters good decision making: Tell yourself what you will or won't do and why (such as, "I will not click on that e-mail from Gilt because I'm saving for a vacation") and you'll be more likely to stick with your goal. Know, too, that friends can help when you're short on self-control. Enlist a trustworthy pal to help keep you accountable by telling her, "I want to have only one glass of wine or cookie tonight" or "Don't let me spend more than $50 at the mall today." Finally, ask yourself, Will I regret this tomorrow? If the answer is maybe, then sleep on it.
Eat for All-Day Energy
After a rough night, skip the energy-drink IV in favor of revitalizing nutrients. "It's amazing how eating the right foods can help you make it through the day," says Lauren Antonucci, RD, the director of Nutrition Energy, a private nutrition-counseling service in New York City. Her meal plan will keep you revved -- and full -- until dinner.
When you wake up: Dehydration compounds fatigue, so down two glasses of water first thing. Aim to sip half your body weight in fluid ounces by bedtime (for a 145-pound woman, that's 72.5 ounces, or about nine cups).
Breakfast: Go for eggs, scrambled or hard-boiled. "They're one of the most absorbable types of protein, with just the right amount of fats and a dose of energy-boosting B vitamins," Antonucci says. For staying power, add healthy carbs, like a slice of whole-grain toast and some fruit. A hit of caffeine will kick-start your day; if java makes you jittery, grab a mug of green tea. It has some caffeine, plus a compound called epigallocatechin, which, studies show, produces a relaxed and attentive state.
Midmorning: Improve your focus with a handful of mixed nuts, such as almonds, walnuts, and peanuts. The protein provides a jolt of energy, while the combo of filling fiber and omega-3 fatty acids tides you over until lunch.
Lunch: Build your meal out of lean protein, slow-burning complex carbs, and healthy fats -- try a skinless chicken breast with a broccoli, black bean, and quinoa salad -- to power through the next few hours.
Late afternoon: Chips or chocolate chip cookies may sound awfully good right about now, but after causing a quick spike in your energy level, they will send it crashing. For a steady, long-lasting pick-me-up, choose nutrient-rich high-fiber foods like hummus with a whole-grain pita or baby carrots.