Kara Goucher is a two-time Olympian and all-around badass. She’s also a sage of running. She gives advice, I listen. So when she told me to start incorporating naps during high volume training I naturally took her word as gospel.
Still, it was hard to put in practice. I’m busy like everyone. Sacrificing precious free time for an afternoon snooze seemed like too high a price to pay.
Then I tried it and I was convinced.
After a big run sandwiched between two days of bigger runs, I marched up to my bedroom. I wanted make Goucher proud but wasn’t expecting much. But after a little tossing and turning, followed by at least 45-minutes of uninterrupted sleep, I woke up refreshed and crushed my workout the following day. Goucher told me that the nap increased my natural production of Human Growth Hormone, or HGH, and helped me recover. Sleep helps athletic performance because the HGH released during shut-eye helps repair and rebuild muscles.
While the benefits of that day’s nap were readily apparent to me, it’s still an open question how much endurance athletes can benefit from naps. It might not always help—and timing seems to be the key.
In a study, published in the Journal of Sport Science, researchers studied how afternoon nap influenced the endurance runners’ performance. For the study, 1 fit and trained runners completed a treadmill run for 30 minutes at 75% VO2 max in the morning and returned to run later in the day for 20 minutes at 60% VO2 max, then to exhaustion at 90% VO2 max.
In one of the trials, a set of runners had a 20-minute afternoon nap about 90 minutes before the evening exercise were compared to a set that didn’t. Researchers found that only some of the runners’ time to exhaustion was improved post-nap.
The lengths of naps might contribute to how much benefit they offer. Studies show that 10-minute naps immediately reduce fatigue and help cognitive performance. Short naps don’t cause sleep inertia, the feelings of sleepiness, disorientation and confusion upon waking from longer bouts of sleep. However, naps of 20 minutes or longer brought sleep inertia. But once sleep inertia is shaken off, a longer nap offers longer-lasting benefits.
But the benefits weren’t felt equally. Researchers found that runners whose endurance most improved after naps had slept less than seven hours the night before. It was a small, single-gender study, so it’s results aren’t conclusive. Nonetheless, it seems reasonable to think that a nap isn’t needed when you’ve had a solid eight hours at night. But if you take an afternoon snooze before an afternoon obligation, pay attention to how long you sleep so you feel refreshed without the pull of sleep inertia.