Are You Getting Enough of the Right Kind of Sleep?

Malia Jacobson
Photo credit: Matt Trappe
Photo credit: Matt Trappe

From Runner's World

To run faster, sleep slower. A growing body of research suggests runners who want to get fast need more slow-wave sleep—the deepest, most restorative stage of slumber. Slow-wave sleep (SWS) is increasingly prized for its ability to help athletes recover from heavy training and hard racing. In fact, many experts say restorative, high-quality SWS is as important to your training as proper nutrition or hydration.

Why is slow-wave sleep important for athletes?

SWS is named for the slow brain waves it creates on electroencephalogram (EEG) tests in sleep labs, which are a sign that the brain has shifted into a repair/prepare mode. During this stage of sleep, memories are consolidated, learning is enhanced, and the brain is cleansed of toxins that may contribute to degenerative brain disease. Also called deep sleep or stage N3 sleep, SWS helps you recover from one day’s workout and prepare for the next.

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Research now shows that even modest deficits in SWS are linked to declines in athletic performance. That’s likely because reductions in SWS are linked to lower levels of human growth hormone (HGH), a compound that affects the body’s ability to repair muscle mass, bones and tendons, says hormone therapy specialist Carissa Alinat, PhD, APRN, founder and CEO of DoctorCarissa.com.

Without enough SWS, the body can’t repair the damage sustained during training and competition, says Alinat. Research on marathon runners shows that the body experiences higher proportions of SWS during post-race sleep, a finding that supports the role of SWS in recovery after metabolic stress.

The body “rebounds” from occasional sleepless nights by increasing SWS for a night or two. This helps explain why you may feel fine and be able to perform well on just a few hours of sleep. But this recovery effect is short lived: As few as 4 or 5 nights of restricted slumber (sleep that’s reduced by around four hours a night) can suppress the amount and intensity of SWS, according to some research.

How much slow-wave sleep are you getting—and how much do you need?

Normal, healthy adults spend around 20 percent of their snoozing hours in slow-wave sleep. That’s a little more than 90 minutes if you get a nightly eight hours. But deep sleep needs vary by age and activity level; endurance athletes and younger adults may need more.

Age and hormones can impact slow-wave sleep, says Alinat. “Around midlife, as women approach menopause and men approach andropause, we see lower levels of slow-wave sleep.” According to some studies, we lose half of slow-wave sleep after age 50 and secrete less human growth hormone as a result. Research links declining HGH secretion to age-related losses in strength and muscle mass, suggesting that decreased athletic performance and the dreaded “last PR” may be rooted in slow-wave sleep.

Photo credit: Matt Trappe
Photo credit: Matt Trappe

It’s difficult to set a baseline for how much deep sleep you need, because it can vary day to day, says certified sleep health educator Martin Reed, M.Ed., founder of Insomnia Coach. Tracking sleep stages is complex and imprecise outside of a sleep lab, so the best way to ensure you get enough SWS is to make sure you clock higher quality sleep: Time spent in deep sleep is a better predictor of athletic performance than overall sleep time, according to a 2016 study of NCAA athletes. And it can protect mood, health, and athletic performance, even when we can’t sleep as much as we’d like, says Reed.

Digital sleep trackers can help you gauge SWS—though not in the way you might think. Wearables and under-the-mattress trackers can’t measure sleep stages accurately, says sleep specialist Michael Breus, Ph.D., author of The Power of When: Discover Your Chronotype. But they can illuminate patterns: Variations in the amount of deep sleep—say, suddenly logging just 30 minutes of it when you usually get 60—or shifts in when deep sleep occurs (like at the beginning of the night versus the end of it) that last longer than a few days may suggest that long-term sleep deprivation or another issue, like increased stress, a new medication, or too much caffeine, is affecting your SWS.

Ultimately, stressing about sleep is counterproductive—the more you worry about it, the fewer zzz’s you’re likely to get. Instead, put your focus on these slow-wave sleep-boosting habits.

Sync your sleep to your body’s natural clock

“Everyone is genetically predisposed to get their deepest, most restorative sleep during a certain time window—some of us wake early, and some naturally stay up later,” says Breus. “When we sleep out of sync with our own biorhythms, we’ll have lower-quality sleep and feel less rested.” For example, when night owls try to get more sleep by turning in early, they may get anxious and frustrated, not sleepy. This reduces what sleep experts call “sleep pressure” or the biological drive to sleep all night, and increases the chances of experiencing insomnia, middle-of-the-night wakings, and poor-quality sleep. Tying your bedtime and wake time to your personal chronotype optimizes sleep stages so slow-wave sleep can do its job.

Find Your Chronotype

Manage your meds

Certain medications, including benzodiazepines , tricyclic antidepressants, barbiturates, opioids, and over the counter sleep aids that contain diphenhydramine can knock out slow wave sleep, says Breus. Instead, try melatonin, which can help you get to sleep faster and may also extend slow-wave sleep. Foods that contain melatonin (a hormone that promotes sleep), like tart cherries (whole or juiced), milk, tomatoes, cranberries, rice, and corn may also help.

Get warm

Raising your body’s core temperature before bed can lead to longer, more restorative periods of uninterrupted SWS, because it supports vasodilation, the widening of blood vessels, which facilitates a gradual cooling of the body, both of which precede deep sleep. Try taking a very hot (around 104 degrees Fahrenheit) bath 90 minutes before bed, move your workout to the afternoon or early evening, or add another layer of clothing in the hours before bedtime.

Skip pot products

Marijuana can help calm anxiety and may even bring on sleep, but research shows that long-term THC consumption may suppress slow-wave sleep. CBD, which doesn’t contain THC, can yield calm, focused alertness that’s good for the workday but not for sleep—research shows CBD can promote wakefulness rather than rest.

Photo credit: Matt Trappe
Photo credit: Matt Trappe

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