But the recent experiments, along with a relaxation of the old 9-to-5 rigidity, have awakened employers to the benefits of on-the-job sleep. A growing number of companies either make nap rooms available to their employees or encourage them to put their heads down on their desks. High-tech firms with a youthful workforce tend to be cooler with on-the-job snoozing than old-line companies staffed mainly by veterans — a contrast that shows up at The Post. The paper’s headquarters in downtown Washington lacks a room dedicated to naps, whereas the company’s Internet operation in Arlington has a small one set aside for that purpose.

According to information collected by the National Sleep Foundation, Toyota encourages naps at its Tokyo headquarters, where they are easy to take thanks to an energy-conservation policy: During lunch hour, the company turns off its lights.

In New York, those who can’t find the peace and quiet they need to nap at work can patronize Yelo, a Manhattan sleep salon.

All this should please Sara Mednick, perhaps napping’s most ardent advocate among the US scientists: She’s so sold on the practice that she calls a napless existence “the madness of monophasic sleep.”

Mednick brings to her discipline impressive credentials — she is a professor in the psychiatry department at the University of California at San Diego.

Last month, Mednick was in Washington to give a talk at the Role of Sleep in Memory and Learning Conference, a co-production of the National Sleep Foundation and the Atlanta School of Medicine. She used slides and cited studies, but above all she projected enthusiasm for her favourite practice.

... contd.