The Worst Time of Day for Productivity

An excerpt from Daniel Pink's "When" discusses the dangers of the "trough," a lull in the afternoon where productivity reaches an all-time low.

Afternoons are the Bermuda Triangle of our days. Across many domains, the trough represents a danger zone for productivity, ethics, and health. Anesthesia is one example. Researchers at Duke Medical Center reviewed about 90,000 surgeries at the hospital and identified what they called “anesthetic adverse events” — either mistakes anesthesiologists made, harm they caused to patients, or both. The trough was especially treacherous.

Adverse events were significantly “more frequent for cases starting during the 3 p.m. and 4 p.m. hours.” The probability of a problem at 9 a.m. was about 1 percent. At 4 p.m., 4.2 percent. In other words, the chance of something going awry while someone is delivering drugs to knock you unconscious was four times greater during the trough than during the peak. On actual harm (not a slip-up but also something that hurts the patient), the probability at 8 a.m. was 0.3 percent — three-tenths of one percent. But at 3 p.m., the probability was 1 percent — one in every one hundred cases, a threefold increase.

Afternoon circadian lows, the researchers concluded, impair physician vigilance and “affect human performance of complex tasks such as those required in anesthesia care.”

Excerpted from When: The Scientific Secrets of Perfect Timing, by Daniel H. Pink, © 2018, Riverhead Books.

For more from Daniel Pink, read our July cover story, “Well-Timed.”

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