"Do you not observe that these athletes sleep away their lives, and are liable to most dangerous illnesses if they depart, in ever so slight a degree, from their customary regimen?"
(Plato, Republic, Bk III)
Sleep is the better half of training, or thereabouts. I learned this from my baby daughter, tiny Zen Master of my days and nights. When she was just a few months old and still figuring out how to move her limbs, she would invent a few new wiggles each day. Then, late at night, we could hear her thump-thump-thumping as she practiced the same moves in her sleep. Next morning we'd find our not-yet-crawling baby girl totally turned, tangled, and backwards in her crib.
It's the same for the athlete. The neural network absorbs training all night long, constellating neurons and ganglia from the shocks and motions of the day's work. So the sleepless athlete gets nowhere.
Re-enter the Zen Master. Nowadays, she crawls, stands, and is cutting teeth. After months of sleeping solidly through the night, she's back to waking us at unkind hours with gale-force bawling. This morning, 4 am found me cradling her against my chest for 45 minutes while her sobs slowly ebbed. It took me another hour after that to fall back into a restless sleep.
I treasure every minute with my daughter, including and especially 3/4 of an hour holding her tight to my drowsy body. I won't be able to solve her problems so easily forever.
On the other hand, I'm nearing the peak of marathon training. Last Sunday, 22 miles, with a fast pickup mile at the end. Tuesday, a bunch of 1-mile intervals at 10K pace (well, a little slower) and some hill sprints. And tonight, another 6.5 miles of tempo running. My legs feel good, but a week's poor sleep has left me soft.
I've learned from experience that my Zen Master always has some important life lesson for me in her visceral riddles. I don't think she's telling me to get less sleep. Probably it's something about being flexible. It's hard to bring it into focus though. I'm just so sleepy.