1. 睡眠的重要性

Other than eating and breathing, sleeping is the most important source of recovery in our lives. In addition to its energy renewing function, sleep is also a period during which substantial growth and repair occurs - most of it at the deepest level of sleep, when slow-wave delta brainwaves are dominant. During those periods, cell division is most active, the greatest number of growth hormones and repair enzymes are released and muscles that have been stressed during the day have an opportunity to regenerate.
In short, we heal and grow most during the deepest periods of recovery.
< The Power of Full Engagement>

2. 什么时候睡觉？

sleep is made up of 2 phases: REM sleep, in which memories and thoughts are processed, and non-REM sleep, in which restorative functions occur and hormones are released to help the body recover. <The Ultimate Guide to Sleep>

As we sleep, we experience 90-minute cycles of these 2 types of sleep.Between the hours of 11 pm and 3 am, most of these cycles are non-REM (restorative), and between 3 am and 7 am, most of these cycles are REM (memory processing).<The Ultimate Guide to Sleep>

因此，为了得到身体最大程度的恢复和修养，尽量在11点前睡觉。我的目前的目标是11点入睡，最终目标是每天10点入睡（6点起床）。

The mean half-life of caffeine in plasma of healthy individuals is about 5 hours. However, caffeine's elimination half-life may range between 1.5 and 9.5 hours, while the total plasma clearance rate for caffeine is estimated to be 0.078 L/h/kg (Brachtel and Richter, 1992; Busto et al., 1989). This wide range in the plasma mean half-life of caffeine is due to both innate individual variation, and a variety of physiological and environmental characteristics that influence caffeine metabolism (e.g., pregnancy, obesity, use of oral contraceptives, smoking, altitude). <Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Chapter 2 Pharmacology of Caffeine)>

咖啡因的半衰期1.5-9.5小时，平均半衰期5小时。因此，10点睡觉，大约下午2点之后就不要摄入任何含有咖啡因的饮品。

午休是另外一个让我们保持精力的办法。

You must sleep some time between lunch and dinner and no halfway measures. Take off your clothes and get into bed. That's what I always do. Don't think you will be doing less work because you sleep during the day. That's a foolish notion held by people who have no imagination. You will accomplish more. You get two days in one-well, at least one and a half, I'm sure. When the war started, I had to sleep during the day because that was the only way I could cope with my responsibilities. Winston Churchill <The Power of Full Engagement>