Today, the Wall Street Journal tells us that, within limits, extra sleep can make up for missed sleep. Plus this:
Recent data suggests that banking sleep in advance of a long night can actually offset upcoming sleep deprivation. "If you knew you were going to give birth on a particular day, for example, you could sleep for 10 hours a day for multiple days before the event, and be fine," he says. Just plan ahead.
Just plan ahead! Who are these people, anyway? Can most of us really just choose to sleep ten hours for a few days in a row even if we don't really need it? Hell, I can't do it even when I do need it. Which has been for approximately the past 20 years.
On the other hand, I'm also pretty unlikely to be giving birth anytime soon, so I guess it all evens out.