How does sleep affect your performace?

If you look at just about any recommendation on training they all tell you to sleep enough. Usually at least 8 hours of sleep every night is recommended. But most people, me included, usually don't sleep enough. So I wanted to know does sleep actually has an effect on my performance, and I did a bit of testing with the data I have. 

I have used Sleepbot to track how much I sleep, and Omegawave to track my aerobic performance and recovery from training. I put their data together and got quite interesting results. 

Let's look at aerobic readiness. This is a simple index from Omegawave which tells how ready you are for an event requiring aerobic performance (for example racing a marathon). The bigger the figure the better. Here is how the data looks like:

As the figure shows, there is quite clear correlation between sleep and aerobic readiness. The readiness goes up when you sleep more, and drops quickly if you don't sleep enough. And the difference is actually quite big: according to Omegawave, 20 points difference in the readiness index is really huge. I you look at the biggest drops in the data it shows that with the worst slept nights (only 6 - 6,5 hours of sleep) the index might drop 20-30 points. Which is a huge difference in peformance. 

So, what do we learn here? Simply - sleep enough. Especially if you are planning to race in an event, it is crucial to get enough sleep before the race.