This key fitness principle can make you more productive at work

If you grind away hour after hour working at a desk, you may not feel like you have much in common with elite athletes.

But if you want to improve at your job or any activity you do — from triathlon-racing to theoretical mathematics to working productively — the equation for getting better is remarkably similar. And it requires a key thing many of us neglect: rest.

The key to improvement and continued success is finding a balance between stress and rest, Brad Stulberg and Steve Magness write in their new book, "Peak Performance: Elevate Your Game, Avoid Burnout, and Thrive with the New Science of Success."

"Success + rest = growth," they write. "This equation holds true regardless of what it is that you are trying to grow."

Contrary to what many of the productivity-obsessed out there may think, the second aspect of that equation is as important as the first.

Stress and rest for athletes

It's easy to see why athletes need rest. Physical exertion, like lifting weights or running long distances, puts stress on the body parts the athlete is trying to strengthen. Those physical challenges actually damage the body. You aren't getting stronger when you lift weight — you are tearing muscle fibers and getting weaker.

It's only during the rest and recovery period that your body begins to heal and adapt so it's better prepared for future stress. Then you can continue, taking on even more weight or distance. But that only works if your rest period was adequate.

This the fundamental principle behind basic athletic training. It's why coaches tell athletes who've been training for months to take an easy week before a big race or event. It's also the reason some athletes do interval workouts, alternating between pushing hard and going easy.

In their book, Stulberg (who writes about the science of human performance) and Magness (a running coach and adjunct professor of strength and conditioning at St. Mary's University) credit physiology researcher Stephen Seiler for some of the first scientific documentation of how top performers across a range of sports follow this same strategy.

"Seiler tracked the training of elite athletes across a variety of endurance sports including running, skiing, swimming, and cycling. He found that, irrespective of sport or nationality, their training followed roughly the same distribution. The best athletes in the world weren't adhering to a "no pain, no gain" model, nor were they doing fitness-magazine popularized high-intensity interval training (HIIT) or random "workouts of the day." Rather, they were systematically alternating between bouts of very intense work and periods of easy training and recovery, even if that meant walking up hills. The ongoing progression and development of elite competitors, Seiler found, was an exercise in stress and rest."

Michael Joyner, a physician and Mayo Clinic researcher who is a world expert on human fitness, previously told Business Insider that one of the most important pieces of advice he gives people is: "Make your hard days hard and your easy days easy."

A similar principle works for creative or professional work as well.

Why taking breaks is key

Research has shown that a cycle of work and rest is key for people learning to master a skill, trying to be productive at the office, or striving for a creative breakthrough.

In "Peak Performance," the authors describe how psychologist Mihaly Csikszentmihalyi — renowned for his work on the concept of "flow" — spent decades interviewing "geniuses from diverse domains," including inventors, artists, scientists, and writers.

"Just as Seiler found that world-class athletes migrate towards a similar style of work, Csikszentmihalyi found that the same held true for creative geniuses: the brightest minds spend their time either pursuing an activity with ferocious intensity, or engaging in complete restoration and recovery. This approach, Csikszentmihalyi discovered, not only prevents creative burnout and cognitive fatigue, but it also fosters breakthrough ideas and discoveries."

The authors write that Csikszentmihalyi found that top performers follow a cycle of total immersion into their work, followed by a disconnected period of rest and recovery. Other productivity researchers have also suggested that regular breaks are essential for people who perform best in fields ranging from computer programming to agricultural work.

This cycle of intense work followed by a real breaks enables the "eureka" moments that are the foundation for breakthroughs — since those revelations usually come when the mind is disconnected from work.

So when your energy runs low or you get stumped on a task, Stulberg and Magness say that's the time to take a break. Get away from what you are doing for at least five minutes — longer if you are particular stressed — and do something that gives your mind a rest from what you were focusing on. That could involve taking a walk, sitting outside, or even taking a shower, but half-hearted breaks spent browsing the internet aren't restorative enough to take your mind out of work mode.

The hard part, of course, is actually doing this. Many of us have been told before that it's important to take breaks, yet we still eat lunch at our desks, half-working and half-browsing the internet.

The key here might be another common bit of wisdom from athletic training: Remember to follow through.