Want to get faster? Sleep slow. Slow-wave sleep (SWS)—the deepest, most restorative stage of sleep—can help you recover from heavy training and races.
Experts now say what and when you eat affects how much slow-wave sleep you get and how well your sleep recharges and restores your body and mind. Along with good sleep hygiene—like sticking to a regular sleep schedule, powering down electronics in the last hour before bed, and keeping your sleep environment dark and quiet—focusing on what you eat (and when) may help boost the quality of your deep slumber.
Time your diet
“Sleep quality is improved if you shift your carbohydrate intake to the morning, which helps avoid a blood sugar crash right before bed and keeps blood sugar more stable overnight,” says Jose Colon, M.D., MPH, a sleep disorders and lifestyle medicine specialist (and avid runner). You may also want to avoid eating in the last hour or two before bed since digestion draws blood and warmth to the core, disrupting the natural progression into deep sleep. If you need a pre-bed snack, choose something light, and with a lower glycemic index—foods with a high glycemic index reduce slow-wave sleep, possibly because they promote inflammation—such as a cup of veggie-rich soup or a small amount of hummus, no less than an hour before hitting the sheets.
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Limit caffeine
Multiple studies show caffeine results in shorter sleep times and less slow-wave sleep. The compound stays in the system for 8 to 10 hours, so steer clear of the pick-me-up, including caffeinated gels and sports drinks, after 12pm.
Hold the booze
Just one or two drinks daily can throw off your sleep stages, resulting in sleep that’s less restorative. While alcohol makes you feel drowsy, it doesn’t allow you to stay in the deeper stages of sleep and may wake you up in the wee hours once its effects wear off.
Eat bright
A balanced, brightly hued diet rich in phytonutrients that reduce oxidative stress can promote better-quality sleep, says Colon. Aim for 6 to 8 servings a day of colorful produce such as spinach, sweet potatoes, dark berries, plums, and squash.
Try intermittent fasting or keto
Intermittent fasting may improve sleep quality, according to some studies, because digestion, particularly breaking down heavy, high-glycemic-index meals, seems to hamper sleep quality. So limiting the hours your body breaks down food could help you sleep better. Other studies show that low-carb and ketogenic diets similarly boost sleep quality and support slow-wave sleep; scientists believe the higher quantities of healthy fats in these diets may be responsible.
Optimize your micronutrients
The following nutrients may increase the depth and quality of your sleep and boost slow-wave sleep to help restore and recharge your body and mind. As always, talk to your doc before trying any new supplement.
L-theanine
An anxiety-reducing amino acid found in tea. Paired with gamma-aminobutyric acid (GABA), a neurotransmitter that calms the nervous system, it can boost slow-wave sleep by 20 percent.
Zinc
Research links the mineral to longer, better-quality sleep and enhanced athletic performance and recovery. Whole grains, milk, oysters, and red meat are good food sources, or pop a daily multi.
Vitamin D
Vitamin D isn’t actually a vitamin—it’s a hormone that can increase the amount of melatonin (the hormone that regulates the sleep-wake cycle) your body creates. Low levels of vitamin D are linked to insomnia and fragmented, poor-quality sleep. Natural sunlight exposure helps the body make vitamin D (and catching rays in the morning may help sync your circadian rhythm so you’ll fall asleep easier at bedtime, too). When sunlight is scarce, find vitamin D in fatty fish, fortified foods, cheese, and egg yolks, or a supplement.
Amino acids
Taurine, which is found in meat, shellfish, and dairy (in lower amounts), promotes deep sleep by helping the brain process GABA. Get it from food or take a supplement hour before bed. Carnitine, an amino acid found mainly in animal products, can improve sleep quality, mood, and performance. Consider takign a supplement if you follow a vegan or vegetarian diet. The naturally occurring amino acid 5-HTP promotes healthy levels of serotonin, which increases “sleep pressure,” the biological drive to fall into a deep, restful sleep at bedtime. To avoid a potentially dangerous overbalance of serotonin, avoid taking 5-HTP with antidepressants.
Phosphatidylserine
This phospholipid improves sleep by reducing cortisol (the stress hormone, which builds up during intense exercise) and regulating circadian rhythms, especially when paired with omega-3 fatty acids DHA and EPA. You’ll find phosphatidylserine in foods such as soy, fatty fish, and liver, but it’s difficult to get enough of these nutrients through food alone, so consider a supplement.
Iron
The mineral is essential to high quality, restorative sleep; deficiency can cause restless legs syndrome and fatigue. Add iron-rich foods like red meat, beans and lentils, tofu, spinach, and cashews to your plate, or take a daily supplement.
Magnesium
Found in dark chocolate, avocados, nuts, seeds and whole grains, the mineral calms the body and mind to prepare for sleep. Get it through your diet or take a magnesium glycinate supplement one hour before bed. Be careful if you get your magnesium through chocolate, however: Chocolate also contains caffeine.
Magnolia bark extract
Research shows it can significantly increase slow-wave sleep by increasing the activity of GABA receptors.
Sources:
Jose Colon, M.D., MPH, sleep disorders and lifestyle medicine specialist; Michael Breus, Ph.D., sleep specialist; Amy Archer RDN, integrative nutritionist; Angela Foster, nutritionist and performance coach; Carissa Alinat, Ph.D., APRN, hormone therapy specialist; Jason Koop, performance coach.
