It pays to sleep on the job.

Critics have been slamming New York Mayor Bill de Blasio for reportedly napping on his City Hall couch for 30 or 45 minutes after he works out every day, with public office frenemy Gov. Andrew Cuomo sniffing that, “I’m not a napper, really, I never have been.”

Maybe Cuomo should take a time out, since many world leaders have sworn by power naps.

Former President Bill Clinton admitted he used to nap in the White House. “On the days when I’m a little short of sleep, I try to work it out so that I can sneak off and just lie down for 15 minutes, a half hour, and it really makes all the difference in the world,” he told CBS News anchor Dan Rather in 1993. Former President Ronald Reagan was also a napper. And British Prime Ministers Winston Churchill and Margaret Thatcher also swore by naps – perhaps because Thatcher famously only got four hours of sleep a night.

Research shows that overworked Americans are accumulating a massive sleep debt – and missing those seven to nine hours of sleep a night costs the U.S. economy $411 billion in lost worker productivity. But catching a cat nap during your 9-to-5 can help beat that late afternoon slump, improve performance and even boost the immune system.

See also: You have to try this scientist’s technique for falling asleep faster

A NASA study on tired military pilots and astronauts found that a 40-minute nap improved their performance by 34% and alertness 100%. Research from the Department of Veterans Affairs Hospital in Northport, N.Y. also concluded that a siesta improved cognitive functioning and alertness by 30%. Short naps also make employers happier and less stressed, and even aids in memory processing, so workers can pick up on new tasks and retain information more efficiently.

Taking a catnap at work can make you feel more energized and productive. (PeopleImages/iStock)

Media mogul Arianna Huffington, who founded Thrive Global to end corporate burnout, has become the patron saint of better sleep. The Huffington Post founder wrote to Moneyish earlier this summer that while naps are not a substitute for a good night’s sleep, “they are very helpful for those nights when you simply don’t get enough – and are a much healthier alternative to caffeine or sugar.”

She installed two nap rooms while at the HuffPo, and says they now have a nap pod at Thrive Global. And workplaces including Facebook, Uber and Google have also cozied up to letting employees take power naps.

See also: Watch this: This desk encourages sleeping on the job

The National Sleep Foundation recommends dozing for just 20 to 30 minutes, which provides “significant benefit for improved alertness and performance without leaving you feeling groggy or interfering with nighttime sleep.”

But many workers don’t have the luxury squeezing in 40 winks in the afternoon. Or, if they have the free time to squeeze in some shut-eye, there’s no peaceful place (or even a spare couch) to decompress.

So the National Sleep Foundation has a couple of p.m. pick-me-ups.

Eat energizing snacks that mix complex carbs with protein, such as veggie sticks with hummus, or a bowl of cereal, which get digested quickly – and creates more energy. Food is fuel, after all. But avoid sweet vending machine snacks or simple white carbs, which cause a rapid spike in blood sugar – followed by a crash that will leave you tired and crabby.

Drink water, since dehydration can leave you feeling more sluggish or fatigued. You’ll want to skip the coffee, though; the caffeine can impact your sleep that night if you’re slipping after 2 p.m. You can swap in green tea to get the same hot drink experience, however. It’s got a lower caffeine count, and the natural antioxidants can also perk you up.

Better yet, take a walk outside to pick up another bottle of water or cup of tea. Moving around will get your heart rate up, and the sunlight will make you feel more alert.

Or recreate your morning routine in the office bathroom – throw some water on your face, brush your teeth or even change your shirt, to recreate that feeling of getting up and going again.