THAT QUICK CATNAP might not always work to make you less sleepy. But a new study suggests a surprising benefit of 30-minute snoozes on the sleep-deprived: less sensitivity to pain.
Experts have known for a while that – among other negative effects on your running and health – slacking on sleep decreases your pain tolerance, says W. Christopher Winter, M.D., medical director of Charlottesville Neurology & Sleep Medicine (who wasn’t involved with the study). That means everything from a hard interval workout to an injury hurts worse.
In the new study, French researchers confirmed this by restricting 11 healthy men to just two hours of sleep, then testing how painful heat, cold, or pressure felt in three spots: upper back, lower back, and thigh. After the nearly sleepless night, participants reported that heat on their lower back and pressure on their upper back hurt more than it did when they were well rested.
Then, the men went through all the tests again, but were allowed to take two 30-minute naps in the morning and afternoon. The siestas didn’t decrease how drowsy the participants felt – in fact, most reported more sleepiness post-snooze. But naps did restore pain sensitivity to baseline levels, essentially reversing the effects of poor sleep on physical suffering.
The results, published in the journal PLOS One, make sense based on previous research, Dr. Winter says. Although not a substitute for a full night’s rest, napping might jump-start some of the crucial recovery processes that occur during sleep, including tissue repair and the release of muscle-building human growth hormone.
Not every participant saw the same degree of benefit, and more research will be needed to confirm the results of the small study, says Matthew Edlund, MD, director of the Center for Circadian Medicine in Sarasota, Florida, and author of The Power of Rest. But since an increasing amount of data points to the importance of shut-eye for athletes’ bodies and minds, he suggests trying a 10- to 30-minute nap during the day and then tracking your training, seeing if the supplemental sleep improves your results.
Dr. Winter agrees and advises runners to try morning naps: “A nap earlier in the day adds to the sleep period before it – whereas one late in the day subtracts from the sleep period afterward,” he says. Napping would likely work better for runners whose sleep was interrupted by an external factor, like a late-night text or an early-morning wake-up call. If you’re prone to tossing and turning, napping may worsen the problem; if your insomnia lingers, consider talking with a doctor or sleep expert about treatment, he says.