This is not an area of research where there’s any reasonable debate; the medical opinion is in: Sleep is good for you, and not sleeping is bad for you in every way—dangerous and potentially lethal. Three recent meta-analyses, comprising millions of research participants, found overall around a 12 percent greater risk of all-cause mortality among those who slept fewer than five or six hours a night.27 If you make only one change in your life after reading this book, let it be getting more sleep.
