When: The Scientific Secrets of Perfect Timing by Daniel Pink offers up evidence that the timing of events has significant influence on the outcome. He contrasts the error rates in hospitals comparing the morning to the middle afternoon. At the same hospital, the patient outcomes are much worse in this low energy time in the afternoon.
There are ways to improve this by taking naps lasting no longer than 20 minutes. People wake up from longer naps feeling groggy. He recommends consuming caffeine, taking a brief nap with a timer set to wake up in 20 minutes. It takes 20 minutes for the caffeine to enter the blood stream so people wake up refreshed and energized. This also works to increase retention of information acquired during a study session. Take care not to consume caffeine late in the day as it interrupts sleep patterns.
Daniel Pink - 7 minutes
When discussion by Daniel Pink - 58 minutes