How adequate sleep can enhance your half-marathon training, marathon training, or triathlon training

Nothing promotes muscle recovery—and full-body recovery—from the stress of exercise like good old-fashioned sleep. In fact, lack of adequate sleep is itself a stressor, so if you consistently under-sleep, you will not recover from your workouts as quickly and you will also be unable to handle as much marathon training or triathlon training as you could handle if you did sleep adequately.

Consider this: As few as four nights of partial sleep deprivation result in skyrocketing levels of the stress hormone cortisol, which inhibits muscle recovery and repair. In addition, research in non-athletes has shown that short-term partial sleep deprivation increases circulating levels of C-reactive protein, a biomarker of inflammation. Therefore, the muscle damage-related inflammation often caused by training is likely to be exacerbated by inadequate sleep.

Muscle Recovery Aside

The impact sleep has on athletic performance doesn’t stop with recovery. Insufficient sleep reduces the body’s ability to process glucose, and therefore to produce energy. Human growth hormone, the muscle-building hormone that plays the biggest role in rebuilding tissue after exercise, requires sleep for full activation, so the less sleep you get, the less muscle you wake up with. Sleep loss also weakens the immune system by reducing the activity of interleukins, molecules involved in signaling between cells of the immune system.
 
The latest neuroscience suggests that sleep even plays a crucial role in relation to motor skill refinements—such as those that make you a more efficient swimmer, cyclist, and runner. During sleep, the brain’s motor center appears to “practice” movements performed by the body during the day. So, in a sense, if you miss out on sleep, you miss out on some of your training.

The Pros and Pillow Time

Looking for real-world evidence that endurance training increases sleep needs? Take a poll and you’ll find that most elite endurance athletes sleep a lot. Marathoner Deena Kastor sleeps 10 hours a night and takes a two-hour nap every afternoon. Most amateur endurance athletes find that their sleep needs increase as their training load does. This may be because exercise causes the muscles to release particular cytokines that induce sleepiness and prolong sleep.

The effect of exercise on sleep needs, however, has been little researched. Some athletes go by propound rules of thumb, such as the suggestion that every mile a runner runs each week increases his sleep needs by 10 minutes per night. But there is no scientific basis for these formulas. They may be accurate for everyone, or just some people, or nobody. We just don’t know.

Snooze So You Don’t Lose

So how do you determine how much sleep is enough? Sleep experts believe that there is a high degree of variation in sleep needs between individuals. It’s best to sleep until you are “slept out,” regardless of how much time it takes. In other words, you should sleep long enough so that you awaken spontaneously in the morning and couldn’t sleep more if you tried. And you will probably find that it takes longer to sleep yourself out when your marathon training or triathlon training is in high gear. Quite simply: Trust your body and do as it tells you.