Talking about how many hours you work is not impressive. Far from being an indication of industrious achievements or alpha status, it should be seen as a professionally embarrassing sign that, quite frankly, you have nothing else to boast about.

Showing off about overwork is now so ubiquitous it’s difficult to remember a time when lack of sleep and hours spent at the office weren’t talked of with a puff of pride. “We just maximize every hour we can, however we can do it,” Twitter executive chairman Omid Kordestani told the Wall Street Journal (paywall) in 2015, explaining that he became chief executive Jack Dorsey’s driver so they could talk business as they commute. “When you hear the so-called apocryphal stories about Tim Cook coming to work in the wee hours and staying late,” Don Melton, who started Apple’s Safari, told Debug podcast in 2014, “it’s not just some PR person telling you stories to make you think that Apple executives work really hard like that. They really do that,” And, of course, just last month, the patron saint of work boasts, Tesla chief executive Elon Musk, declared that “nobody ever changed the world on 40 hours a week.” Musk said in November that he worked 120-hour weeks, and on Twitter claimed that 80 to 100 hours per week is necessary to change the world.

As countless studies have shown, this simply isn’t true. Productivity dramatically decreases with longer work hours, and completely drops off once people reach 55 hours of work a week, to the point that, on average, someone working 70 hours in a week achieves no more than a colleague working 15 fewer hours.