You can also let your son know that the arbitrary cutoff of adulthood for sleep requirements — see the chart in the story — is suspect. There's no scientific reason to think a 19-year-old needs less sleep than an 18-year-old. I discuss this in my book as part of a broader take on how unfortunately generalized and questionable the recommendations are for all adults. Bottom line: Each person needs to find the # of hours that makes them feel well-rested (and I go into great detail on how to figure this out).