The federal Centers for Disease Control and Prevention calls sleeplessness a public health concern. Good sleep helps brain plasticity, studies in mice have shown; poor sleep will make you fat and sad, and then will kill you. It is also expensive: Last year, the RAND Corporation published a study that calculated the business loss of poor sleep in the United States at $411 billion — a gross domestic product loss of 2.28 percent.

Companies now fight “presenteeism,” a neologism that describes the lackluster performance of foggy-brained, sleep-deprived employees, with sleep programs like Sleepio, an online sleep coach, and sleep fairs, like the one hosted last month in Manhattan by Nancy H. Rothstein, director of Circadian Corporate Sleep Programs and otherwise known as the Sleep Ambassador, for LinkedIn. For the last few years, Ms. Rothstein has been designing sleep education and training programs for a number of Fortune 500 companies. At the LinkedIn sleep fair, she taught attendees how to make a bed (use hospital corners, please) and gave out analog alarm clocks. (It was her former husband’s snoring, she said, that led her to a career as a sleep evangelist.)

If sleep used to be the new sex, as Marian Salzman, a trend spotter and chief executive of Havas PR North America, proclaimed 10 years ago, today it is a measure of success — a skill to be cultivated and nourished — as a “human potential enhancer,” as one West Coast entrepreneur told me, and life extender.