The researchers found that children ages two and older who napped took longer to fall asleep in the evening, and slept for less time across the night, than those who did not.
Napping—or not napping, for that matter—did not seem to have any significant effect on the children’s behavior or health.
Although the study was published in a prestigious journal, I’m sure that the findings come as no surprise to most parents, who observe this in their daily lives and those of their children.
Because sleep is a state during which the brain consolidates memory, processes experiences, and regenerates itself, each of us requires a certain amount of sleep per 24-hour day. This is similar to other needs of the body, such as food and drink. The body is not set up, however, to “bank” sleep, and so once the necessary amount is achieved, the brain no longer demands sleep. This makes sense, as if we were able to continue to sleep unless interrupted, we’d be hard pressed to do everything else we need to in order to survive such as to eat, seek shelter, reproduce, care for our young, etc.
One way of understanding this is by imagining the 24-hour day as a pie, of which we can eat a certain amount. We can take it all in one piece—which is how most adults do it—or we can break it up into pieces, which is what happens when we nap.
The take-home message is that as long as your child receives an age-appropriate amount of sleep during the 24-hour day, it really doesn’t matter whether or not it’s in one block or two. However, if getting your kid into bed earlier rather than later in the evening is important to you (and your sanity), it may be worth considering whether it isn’t time to phase out that nap.
Dennis Rosen M.D.