Nevertheless, frenzied corporate cultures still confuse sleeplessness with vitality and high performance. An ambitious manager logs 80-hour work weeks, surviving on five or six hours of sleep a night and eight cups of coffee (the world’s second-most widely sold commodity, after oil) a day. A Wall Street trader goes to bed at 11 or midnight and wakes to his BlackBerry buzz at 2:30 am to track opening activity on the DAX. A road warrior lives out of a suitcase while traveling to Tokyo, St. Louis, Miami, and Zurich, conducting business in a cloud of caffeinated jet lag. A negotiator takes a red-eye flight, hops into a rental car, and zooms through an unfamiliar city to make a delicate M&A meeting at 8 in the morning.

People like this put themselves, their teams, their companies, and the general public in serious jeopardy, says Dr. Charles A. Czeisler, the Baldino Professor of Sleep Medicine at Harvard Medical School.¹ To him, encouraging a culture of sleepless machismo is worse than nonsensical; it is downright dangerous, and the antithesis of intelligent management. He notes that while corporations have all kinds of policies designed to prevent employee endangerment—rules against workplace smoking, drinking, drugs, sexual harassment, and so on—they sometimes push employees to the brink of self-destruction. Being “on” pretty much around the clock induces a level of impairment every bit as risky as intoxication.

As one of the world’s leading authorities on human sleep cycles and the biology of sleep and wakefulness, Dr. Czeisler understands the physiological bases of the sleep imperative better than almost anyone. His message to corporate leaders is simple: If you want to raise performance—both your own and your organization’s—you need to pay attention to this fundamental biological issue. In this edited interview with senior editor Bronwyn Fryer, Czeisler observes that top executives now have a critical responsibility to take sleeplessness seriously.

I wonder what America would look like if everyone got eight hours of sleep and got half an hour of exercise every day.