Catching more quality ZZZs can make you a stronger, better runner.
Status Update: Late night last night. Still managed to get up at 4, knock out a 28K run, and get the kids to school on time.
Status Update: Didn’t get enough sleep this week. Stayed in bed for an extra hour and skipped my run.
Let’s say these two status updates showed up on your Facebook or Strava feed. Which would get more ‘likes’? If you’re like many runners, you probably admire the badass who fought through fatigue to complete her run and suspect that the slumbering beauty is a slacker.
Our society views sleep as a luxury, at best. Many people think that revealing your need for it marks you as a weakling, says John Caldwell, Ph.D., a psychologist who has researched sleep deprivation and fatigue for NASA and the US military. “We think if you’re really a good athlete, that means you’re tough and you’ll take whatever life throws your way,” Caldwell says. “Part of being tough is not needing to sleep.”
By that line of reasoning, some of the top marathoners rank as total slouches. After all, Ryan Hall pens naps in his calendar as ‘business meetings’, and both Deena Kastor and Shalane Flanagan log as much as 10 hours of shut-eye a night. They clearly understand what science is increasingly revealing: it’s during sleep that your body recovers from hard training and builds you into a better runner.
Indeed, recent research suggests that just one night of bad rest can have an impact (albeit largely psychological) on your running performance. Meanwhile, chronically shorting yourself of even an hour of sleep per night has cumulative negative effects on your running and your health. “Sleep is as important as your workouts,” says Joe English, a running coach. “When you start robbing from that pot to get everything else done, the quality of your training – and of everything else – starts to fall apart.”
No lab test can tell you exactly how many hours of sleep you need – the number varies widely by individual. But the average adult needs between seven and nine hours each night, says Matthew Edlund, M.D., director of the Center for Circadian Medicine in Florida, USA, and author of The Power of Rest. Not surprisingly, how much you run impacts how much you need to sleep, but it’s not a simple more-means-more equation. Research has linked moderate exercise to higher-quality, more efficient slumber – possibly by increasing levels of a compound called adenosine that promotes sleep. And so, people logging moderate mileage might actually need less sleep than those who don’t run at all. But as anyone who’s ever trained for a half-marathon or longer can attest, sleep needs can change at the start of a new running program or in the midst of a tough training cycle, says Cheri Mah, a Stanford University sleep researcher. There’s not yet a handy chart for correlating weekly mileage to required hours of sleep.
Your body will likely supply some cues when you don’t get enough. You’re likely short on Z’s if you fall asleep the second your head hits the pillow, you find yourself dozing off during meetings or at the movies, you rely on caffeine to get through the day, or you hit the snooze button more than once. “If your body is literally going back to sleep immediately after being asleep all night long, you are probably not getting enough sleep,” says Robert Oexman, D.C., a runner and the director of the Sleep to Live Institute in North Carolina in the US.
Ignore these signals at your peril. “When you don’t obtain your required amount of sleep, it can build up like a debt, almost like a credit card,” Mah says. Most of us have racked up some, sleeping six hours or less each night. “Over time,” Mah says, “that accumulated debt can affect performance and mood.”
While You Are Dreaming
Night after night of restricted (or interrupted) sleep – where you rest some, but not enough – sets off a cascade of hormonal shifts with harmful biological effects. Within a week or two, you’ll have higher levels of the inflammatory marker C-reactive protein and the stress hormone cortisol, keeping your heart rate higher and your nervous system on constant alert.
Human growth hormone, which repairs muscle and bones, is secreted by your pituitary gland during deep sleep, says Shelby Harris, director of the Behavioural Sleep Medicine Program at Montefiore Medical Centre in New York. The less sleep you get, the lower your levels – and the slower your recovery from workouts or minor aches and pains. Your muscles’ ability to store glycogen for energy declines, meaning you risk running out of gas no matter how much you carb-load, says Harris, who is also a runner. There is also some research that indicates your risk for injury goes up if you don’t get enough shut-eye.
Sleep also serves as a time for memory consolidation, Dr. Edlund explains – and not just for cognitive skills, like maths or a second language. “Running is a very big learning experience,” he says. As you train, your brain takes in information about the world around you, the way muscles and nerves must work together to power each stride, and the way your body position shifts in space (proprioception), he explains. It’s during sleep that you process, synthesise, and catalogue these details, and skimping means the memory-related areas of your brain don’t file away as much as they should.
Being sleep-deprived doesn’t just make you tired, but also jittery, achy, and injury-prone. There’s no magic number of hours that protects you from poor performance or from running-related pains – again, everyone’s sleep needs differ, Dr. Edlund says. But the more nights you get less than your required amount, the greater the potential consequences to your running.
And in the bigger picture, you’re probably harming your overall health, too. Sleep deprivation throws your hunger hormones out of whack, increasing levels of the hunger-inducing ghrelin and decreasing satiating leptin, Harris says, which in turn may cause you to eat more and gain weight. In addition, not getting ample sleep suppresses the immune system (leaving you susceptible to infection); your mood can sink down into the dumps; and your risk for developing chronic diseases, such as type 2 diabetes, rises.
Toss and Turn, Crash and Burn?
Runners know insomnia is common the night before a big race. But they take comfort from this often dispensed piece of wisdom: “It’s not your sleep the night before a race – it’s the night before the night before that counts.” Anecdotal evidence bears this out. No one sleeps much the night before an Olympic race, says Paula Schnurr, who ran the 1500 metres for Canada in the 1996 Summer Olympic Games. Few first-time marathoners rest well either, English says. But many perform well anyway, fuelled by race-day excitement and adrenaline.
Research supports this hypothesis, to a degree. When scientists keep people up all night and then ask them to cycle, lift weights, or run on a treadmill, they can do it just as well as when they’ve slept. But interestingly, they report that each kilometre or rep feels harder and they often don’t want to put forth the effort. “In order to run a good race, you have to be in a state of mind where you’re going to push it,” Caldwell says. “We’ve known for years that sleep deprivation typically doesn’t really affect absolute things like muscle contractions, speed and power. But it definitely affects your willingness to perform your best.” When you head out for a training run sleep-deprived and with no cheering crowds or competition, these deficits could lead you to slack. As a result, you might not give your body a strong enough stimulus to adapt and improve your running, English says. What’s more, lack of sleep impairs cognitive function and reaction times, which could put you at risk of a collision if you’re crossing busy streets or running on a crowded path or rocky trail, says neurologist Lev Grinman.
In fact, if you’ve slept fewer than about six hours, you might benefit more from staying in bed an hour longer than from forcing yourself to stumble out on a run, says Shawn Youngstedt, Ph.D., an exercise physiology researcher at the University of South Carolina, US, who is also a runner. Even top coaches and athletes sometimes follow this guidance. Schnurr – now the head track coach at McMaster University in Ontario, Canada – says she can tell when her student athletes show up to practice without having slept well. She often modifies their workouts or sends them home from practice entirely, knowing they wouldn’t reap the benefits of a tough training session while sleep-deprived.
Many people can bounce back quickly from one or two nights of poor rest. But performing well gets harder the longer you’re deprived. “I’ve had some really good races after I didn’t sleep for one night, but I’ve never had a good block of training while sleeping poorly for a few months,” says Hansons-Brooks athlete and former NCAA 5K champion Bobby Curtis, who has suffered from bouts of insomnia.
Avoid an Energy Crisis
When Mah asked Stanford basketball players to sleep up to 10 hours a night for five to seven weeks, they performed better on the court. She found similar results in swimmers, too. Now, spending almost half the day in bed isn’t a luxury most of us can afford – and it may not even be necessary. Your body’s optimal amount could be seven hours; it could be eight. Harris recommends determining your ideal sleep pattern when you have a weeklong vacation or other situation that doesn’t require a strict schedule: don’t use an alarm clock, wake up naturally, and take note of what time you went to sleep and got up. By the fourth day, you’ll have caught up on sleep debt; take the average amount of sleep you get on nights four through seven for a good estimate of your true needs, she says. Once you’ve figured out about how much sleep your body naturally wants, schedule your bedtime in advance, just like you would any other commitment, Caldwell advises.
Mah says that runners can still benefit from ‘sleep-loading’ – getting extra shut-eye in the week or two before beginning a training program that ramps up your mileage. Committing to just a half hour more each night to pay off your sleep debt in between training cycles enables you to kick off a new program refreshed and strong. “That’s a half hour less texting or checking your e-mail, or catching up on your favourite TV shows,” Mah says. And, of course, there’s the chance that you’ll feel so good during this period of time that you might decide to make an earlier bedtime permanent.
Experts also recommend tracking your sleep – just like you log your KMs – in order to help you correlate your rest to your running performance. While that won’t give you more hours in the day, it may help you place sleep and training on equal footing. “If you’re obsessed with logging your runs, try to be as obsessed with logging your X hours of sleep a week,” English says. “When you do, it’s going to really positively impact the quality of your workouts.”
Keeping track can also help you recognise if something goes awry in your training. In a recent study in the journal Medicine and Science in Sports and Exercise, athletes who overreached – or who ran more kilometres, or did more intense workouts, than their bodies could handle – showed disrupted sleep patterns, possibly because of an overactive autonomic nervous system (the part that controls your heart and other internal organs. if you’re unable to sleep well, it could mean you need to cut back or incorporate more rest days to absorb all the hard work you’re doing, says study author Yann LeMeur, Ph.D., of the National Institute for Sport, Expertise, and Performance in Paris, France.
Finally, monitoring your sleep habits often gives you a bigger-picture view of whether your goals mesh with your life at the moment, Harris says. If you just had a baby and you’re also studying for a master’s degree, for instance, now may not be the time to train for your first half-marathon. “You really have to be realistic – maybe you just can’t get up at 5 in the morning to run if you can’t go to bed until midnight,” Harris says. You don’t have to stop running – remember, runners tend to sleep better – just consider whether you should scale back expectations, or run for stress relief rather than trying to stick to an aggressive plan. On the flip side, if you have an ambitious goal – say, setting a new PB or qualifying for Boston – plan it for a time when you can rearrange your life to accommodate the training and recovery necessary.
If you happened to be Facebook friends with Hall, he’d probably tell you the same thing (and he wouldn’t like a post about skipping shut-eye). “I rarely stay out past 9 pm when I am in hard training, and I always protect my ‘business meetings’ by not scheduling any phone calls or appearances in the afternoon,” he says. “It is the most crucial part of my training. If I cannot recover from my training, then there is no point training.”