Charles Darwin worked about four hours a day; Gabriel García Márquez, five hours a day; and Ernest Hemingway, six hours a day.

These folks were well known for their output despite the small number of hours they worked every day. But here’s the thing: They weren’t lazy. They were efficient. And now there’s a whole lot of evidence to suggest that a few hours of intensive practice a day is optimal for achieving success.

Science is showing that you can actually get more done in less time and that if you work too much, you are not only inefficient, you might actually be holding yourself back. So can you actually reduce your hours? It would seem yes, as long as you know how to use the hours you work properly. The secret appears to be that your work must be deliberate and you must engage with full concentration.

Here’s how to do it.

Focus – Theodore Roosevelt, former President of the United States, was a boxer, poet and naturalist. He was an insatiable reader and a prolific writer. Apparently he didn’t work long hours. He liked to nap and pursue a number of extracurricular activities. His secret? During the few hours in the day that he worked, he focused. Everything else got put aside, and he invested himself entirely in the task at hand.

Don’t multitask – There are so many distractions, but you need to ignore them. This isn’t easy in the age of smartphones and the quick dopamine hits they offer. Nowadays, the sad reality is that the average attention span is about eight seconds. The experts say that trying to do multiple things at once limits you and actually ends up with your getting less done.

Daniel Weissman, a neuroscientist at the University of Michigan, has concluded that even simple tasks can overwhelm the brain when you try to do several at once. In fact, the concept of multitasking has largely been debunked. You can’t really do two things at once. In reality, what you’re doing is task switching. Not only is this inefficient, it’s mentally exhausting.

Take breaks – No matter how smart you think you are, the research says that you can’t maintain brain power throughout the whole day without some rest. In fact, there are studies to suggest that workers are more productive when they have a fifteen-minute break every couple of hours. This doesn’t mean you read the news or scroll through social media. You actually have to sit back and relax…let your mind wander. Work deliberately, rest deliberately…that’s the trick.

Have a nap – Again, science has spoken. Naps help with alertness and perception and cut through the fog that creeps in during the day. So take a nap (even at work) and don’t apologize for it. It’s probably better to do this during your break. Despite the science, the boss may not appreciate you slouched over, drooling on your keyboard.

Despite these tips, you need to face the reality that success requires a lot of work. Expertise still requires those famous 10,000 hours. However, that doesn’t mean twelve and fourteen hour days. It does mean focused, hard work for a few hours every day along with rest and a few enjoyable activities. If you can’t manage that, get a new job.