You may live longer but you may not be awake longer. I find that the 16 hours I have after clocking 8 hours are infinitely more "awake" than the 19 hours I get

You may live longer but you may not be awake longer. I find that the 16 hours I have after clocking 8 hours are infinitely more "awake" than the 19 hours I get when I only clock 5. Which is basically what the sleep researchers say. The bottom line is that there's clearly a tipping point, not the same for everyone of course but averaging around 7 hours, below which "wakefulness" (and functioning metabolism in general) experienced throughout the rest of the day rapidly starts to tank.