The other one looked at a little bit less, so 45 minutes of extra sleep per night, but for a longer duration, this was now 3 weeks. And they found an improvement in reaction time by 4%, as well as a reduction in cortisol by 19%. This was in rugby players.

And these data are very well-rounded from a number of areas—the NFL, the NBA, the NHL, the Olympics, PGA Tour, etc., etc.—there is clear and impressive evidence that those who maximize their sleep win more games.

This is really what set the field on fire... You're talking about Division 1 athletes that have 9% improvements in shooting accuracy over the course of a season by sleeping 2 additional hours per night.

I'm completely obsessed with this topic... and that's because the data are so robust and impressive about what happens when you optimize sleep performance. So again, I'm not really talking about the consequences of bad sleep on your long-term health or things like that; it's the opposite—it is how much of an advantage you can create in your performance when you sleep better.

One of them looked at an additional 1.7 hours of sleep per night over the course of a week, and this was done in tennis players, and they found that it improved tennis serving accuracy by about 6% or so.

In fact, over 80% of the research on sleep and athletes has been published in the last decade alone.

He basically said, when working with one particular NFL team... sleep extension was incredibly powerful at helping people return from injuries.

Athletes tend to sleep less and worse than non-athletes despite the fact that they probably actually need more sleep.