Exercise is often touted as the antidote to everything from depression to insomnia. “Take a brisk 10-minute walk on your lunch break and power through that glass ceiling!” magazines often advise (note to mags: What does one do about the sweat on one’s power suit? Because I’m not changing into my running tights and Nikes for 10 minutes.) But what if exercise works against you?
Gym Buddy Allison made an interesting observation on the stretching mats (a.k.a. the mats of ill repute) the other day as we navigated the damp spots of other people’s bodily fluids in order to find a dry spot to leave ours on.
“How much do you sleep?”
I shrugged, “As long as my kids will let me.”
“No,” she said, “if nobody woke you up and you could sleep as much as you wanted, how long would it be?”
Most nights I get 6-7 hours of sleep. I feel like busting out the Rodgers and Hammerstein if I get 8. Nine hours and not only would The Hills be Alive but I might actually do something about the hills of laundry in bedroom. So I replied intelligently, “I don’t know.”
“Because I’ve noticed that I need about nine hours, maybe even a little more, per night to feel really good. Plus I usually end up taking a nap every afternoon.”
“Okay, that’s still in the range of normal.” Secretly I’m jealous her sons let her sleep that long. Okay, it’s not really a secret.
“Not for me! I used to only need 7 or 8 hours of sleep a night.”
“What changed?”
She cocked an eyebrow. “This. Our workouts.”
And the light went on. Since that conversation about a week ago, I’ve been paying a lot more attention to how my need for sleep correlates with my exercise. You can probably file this under “duh” but the more I exercise, not only do I get hungrier, but I need more sleep. Apparently I am the least introspective person on the block as this revelation was surprising to me.
Deena Kastor, of Olympic fame, reportedly sleeps 10 hours a night in addition to taking a two-hour nap every afternoon. This phenomenon is well documented in high-caliber endurance athletes. Steven Spence, another elite marathoner, says that when he trains he literally sleeps half his life away, needing 12 hours a night. Between eating – Kastor eats about 3,000 calories a day to maintain her svelte 105 lbs – training and sleeping, an athlete’s life may not consist of much else.
As Gina Kolata from the NY Times points out:
It’s one of the mysteries of sleep: Why is it that mild exercise can be invigorating, but strenuous endurance exercise — whether it’s crew practice, long runs as training for a marathon or juggling back-to-back workouts to prepare for a triathlon — makes people groggy?
Wannabe Jocks
I am not training for anything. I’m certainly not an Olympian. In fact, while I exercise for many reasons, one of the primary reasons I love it is because it gives me more energy. Except when it doesn’t. I had chalked up my increasing fatigue to a busier schedule and and children that reappear like groundhogs for two hours every night after we “put them to bed.” But it seems I need to lay some of the blame at the feet of my workouts. I’ve talked before about how after a particularly gruelling workout, I’ll be overcome with an overwhelming need to sleep. As in immediately. After starting CrossFit, I remember one day where I literally fell asleep on the kitchen floor while my kids ran circles around me. But I thought these were isolated metabolic events not a pattern. I didn’t notice the sleep creep until Allison pointed it out but she’s right.
Research
According to Dr. Alex Chediak, president of the American Academy of Sleep Medicine, says that while nobody is sure exactly how or why endurance athletes need more sleep – “Runners are more of a curiosity. And because intense endurance exercise isn’t what most exercisers do, it is not even feasible to reason by inference.” – he thinks it has to do with the release of cytokines, the hormones that signal the immune system.
Kolata further explains:
Exercise prompts muscles to release two cytokines, interleukin 6 andtumor necrosis factor alpha, that make people drowsy and prolong the time they remain sleeping. In fact, those cytokines also are released when people have a cold or infection, which is why people sleep so much when they are ill.It turns out that the single most important factor for increasing the release of those two cytokines is increasing the duration and intensity of exercise, Dr. Chediak said. And, he noted, that’s what is happening when endurance athletes train. “A sprint will not get you as great an effect,” he said.
This is not what I want from my workouts. I want my exercise to energize me, not deplete me. I think it is obvious from this blog that I often suffer from a more-is-better mentality. Allison summed up the problem perfectly, “Over the past year, I’ve had to add an hour of sleep per night. I want that hour back.” So now I want to know:
Have you ever noticed this effect? And where is that point of diminishing returns? How long should a workout be to give you the energy without the drag? How many hours a night do you sleep?
Written with love by Charlotte Hilton Andersen for The Great Fitness Experiment (c) 2011. If you enjoyed this, please check out my new book The Great Fitness Experiment: One Year of Trying Everything