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How Sleep Deficit Is Killing Your Athletic Performance

If sleep deficit is chronic, the effects become physiological.

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Eight hours of shut-eye a night, maybe more in heavy training phases—that’s the goal. But by the time you add in work, family, a rudimentary social life, basic home biohazard control, and dental flossing, you’re looking at six hours—if you’re lucky.

But what the heck, if you’re walking and talking like a boss, is lack of sleep really affecting your athletic performance?

According to Steve Magness, sports scientist, coach and author of Peak Performance, it’s a matter of degree, duration, and understanding what you’re dealing with: sleep deprivation or sleep deficit. Sleep deprivation refers to total lack of sleep, usually for a limited amount of time. Sleep deficit happens when you’re chronically getting below optimal sleep levels. “So, if you’re only getting five hours of sleep a night five days out of the week, you’re building a sleep deficit of two to three hours a night that accumulates over time,” Magness says. The greater the deficit, the greater its effect on athletic performance.

Most studies, Magness says, use sleep deprivation, keeping participants awake for anywhere from 24 to 48 hours. Mentally, results show some lack of alertness, slower reaction time and slightly reduced cognitive ability, but little reduction in muscle function or power output. Good news!

“So, a night here or there of poor sleep, or not sleeping the night before a race is not going to have much effect on performance,” he says. “That is, if the athlete is healthy and generally well rested.”

Sleep deficit, on the other hand—the category lots of busy people fall into—does affect athletic performance. “Psychological effects show up before large physiological effects—things like increased perception of effort—everything seems harder—giving up on the task sooner, less willpower, increasingly negative thoughts and outlook.”

If sleep deficit is chronic, the effects become physiological. Stress hormones—specifically cortisol—stay elevated, and growth hormones meant for muscle repair drop. Chronically elevated cortisol levels are not only a result of sleep deficit but can also keep you awake in the limited amount of time you’ve got between the sheets, so the problem snowballs. “Elevated cortisol levels cause your body to stay in a catabolic state—muscles are breaking down, and at the same time, the repair process is impeded,” Magness says.

The result? Endurance drops, actual power output is reduced, chance of injury increases, and that’s on top of the mental muck that’s happening between the ears.

“It’s a matter of degree,” Magness says. “If the race is short enough or the sleep deficit not that great, there’s a possibility there’d be no impairment of performance. But in an endurance event, even if the deficit is just enough to produce a negative mood or greater perceived effort without affecting actual muscle function, performance will be affected detrimentally.”

Part of athletic success is overcoming obstacles, like the sleep deficit that comes with a night class or a new baby. Magness suggests some real-life hacks for minimizing real-life sleep deficit. For example, go to bed an hour earlier in the week prior to a race. By banking sleep against travel days or night-before nerves when you know you’re not going to sleep well, you ensure sleep loss doesn’t affect you as much.

Sometimes it’s easier to fit in an hour of down time during the day than tacking it on at night. “Naps are important. If you’re not getting enough sleep on a regular basis, naps make you feel a lot fresher. It’s a psychological boost,” he says.

And day of race? “Taking caffeine before a race counteracts sleep loss, at least temporarily, and helps with mental focus,” says Magness.

One caveat: Over-the-counter sleep aids, Magness warns, may help you sleep initially but come up short in quality of sleep. When you factor in residual morning sluggishness, they’re really not a
practical solution.

RELATED: A Triathlete’s Guide to Sleep

Snooze for Recovery

Don’t just lie there—harness the power of advanced sleep technology. While these products can’t guarantee more hours of shut-eye, they claim to make your sleep more comfortable, more restful, and thus more effective in aiding recovery.

Under Armour’s Tom Brady Recovery Sleepwear is printed inside with a “bioceramic” material that absorbs body heat and reflects it back to the skin as far infrared, a type of thermal radiation that’s known to stimulate recovery in cells and tissue.

Sheex Performance bedding transfers nearly 50 percent more heat and moisture away from your body than cotton sheets. More comfortable sleep is more restful sleep, the Sheex peeps figure.

Bear foam mattress seems to do both, reflecting back healing infrared radiation and keeping you cool and comfortable via better airflow. Bonus: It’s also made from eco-friendly foam.

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