Today is world sleep day. In celebration, I urge you all to drop everything and take a nap. As I mentioned back in April last year, research has shown that getting 8 hours of sleep a night is important for optimal cognitive function. We all know how crappy we feel when we’re sleep-deprived. Brain fuzz takes over. We start to yawn uncontrollably in an effort to oxygenate our exhausted neurons. Our eyes start hurting and feeling dry, prompting us to rub them for relief. Every horizontal surface starts to look attractive. But there is a lot more to it than just feeling lousy.