Sleep Well: What to Eat for Better Sleep

Sleep and Your Diet

Jenniffer Jordan, 34, was at soccer practice with her local team when she first made the connection between the food she ate and the sleep she was -- or, rather, wasn't -- getting. "My teammate started raving about her surge in energy thanks to a new 'whole foods' approach to meals," Jenniffer says.

"I was so tired all the time. I seriously thought I had a sleep disorder. Suddenly I wondered, could it be my diet?" After hearing her friend describe how she was sleeping better and waking up raring to go, Jenniffer decided to clean up her act. Out went caffeine and alcohol; in came fruits, vegetables, and lean meats. Up went her water intake; down went the consumption of high-sugar snacks. "Within a few days I was sleeping sounder, feeling stronger, and having more energy," Jenniffer says. "Before, I could barely wake up for work; now when my alarm goes off, I feel good." An added perk: better workouts. "Three-mile runs used to feel tiring; lately I'm going longer and faster. Who knew changing my diet would start this chain reaction?"

Her epiphany about the diet-sleep-fitness connection is one we could all benefit from. For starters, the amount of sleep women get has declined in recent years: On average, we sleep six hours 40 minutes on weeknights, according to a 2009 National Sleep Foundation poll. Just seven years ago, we were getting six hours 54 minutes, and a century ago Americans averaged nine to 10 hours a night.

At the same time, obesity rates in the United States have skyrocketed, reports the Centers for Disease Control; 66 percent of adults are overweight or obese. Snoozing dips, sizes rise -- coincidence? Probably not. "When you're sleep deprived, your body produces more ghrelin, a hormone that tells you to eat more, and less leptin, which signals you to stop eating," says Michael Breus, PhD, author of Beauty Sleep. Case in point: People who sleep only four hours a night are more likely to choose high-carb, sugary, and starchy foods over healthier picks, a recent University of Chicago study found.

The reverse is also true: Eating certain healthy foods calms your nervous system and triggers a sleep-inducing hormonal response, scientists say, helping you rest better at night.

Getting enough zzz's is particularly important for active women. "Sleep allows your body to recover from tough workouts and readies it for the next one," says Kristine Clark, PhD, RD, director of sports nutrition at Pennsylvania State University. "During deep sleep, every muscle in your body works to rebuild itself stronger than before."

The seven to eight hours of sleep a night that experts say women need may sound like a lot, but just wait: Active women, especially those training for an endurance event, need up to 10 hours for peak performance, says James B. Maas, PhD, professor of psychology at Cornell University and coauthor of the forthcoming Sleep -- At Last! "Well-rested people are typically 20 percent quicker at performing physical tasks than those who lack adequate rest," he says. "Sleep plays a major role in muscle memory, which sharpens your focus and reduces reaction time."

When researchers at Stanford University asked tennis players to sleep 10 hours a night for five to six weeks, the athletes reported sprinting faster and hitting better. Equally important, they felt that they recovered quicker for the next day's practice than when they worked out with fewer hours' rest.

How exactly does sleep help you get fitter? During rapid eye movement sleep (REM), neural connections created during your workout are strengthened, ingraining a new skill (like a tennis serve) into long-term memory, Maas says. In stage 2 of sleep, small bursts of brain activity promote muscle memory for step-by-step actions (like a kickboxing sequence). And slow-wave sleep helps the body produce hormones essential for muscle repair.

On the flip side, too little sleep can slow down your workout. "Studies show that poor sleep quality has the same negative effect on performance as not sleeping at all," Maas says. "In both cases, the body's ability to convert sugar into muscle fuel slows, so muscles don't receive enough energy, causing you to 'hit the wall' during exercise 20 percent sooner."

In other words, eat smarter, sleep better; sleep better, get fitter. It's that simple. Start with the nutrition strategies on the next page for sweeter, sounder dreams tonight and a stronger body tomorrow.