For nearly 15 years, I’ve been making the case — in my writing and with corporate clients — that employees can be more productive by working fewer hours and taking more time for rest and renewal during the work day.

At my company, the Energy Project, we’ve tested this assumption over the years by progressively reducing the number of hours we ask employees to work.

Our hours are truly 9 a.m. to 5 p.m., and we encourage all employees to take an hour off for lunch, away from their desks. If people want to take a nap or work out during the day, we support that. We don’t expect them to send or reply to email in the evenings or on the weekends. We provide five weeks of vacation for first-year employees, and seven weeks for those who’ve been with us more than five years.

So how do we get anything done?

Each time we’ve opted to give our employees more time for rest and renewal, I’ve wondered anxiously if we’ve finally gone too far. But every year since 2009, our revenue and profitability have significantly increased. So, too, I believe, has the quality of the work we do and the value we provide to our clients.

I believe our approach is effective for the same reason that interval training is an efficient way to work out. You get more accomplished by working intensely for short periods and then refueling than you do by working continuously over a long period of time. None of us can operate continuously at peak levels for very long.

The psychologist Daniel Kahneman, who won the Nobel in economics for his work in behavioral economics, conducted one of the most fascinating studies in this area. Along with several colleagues, Mr. Kahneman set out to study “diurnal rhythms” — those that occur at predictable times every day — among 909 working women. The goal was to assess whether the way people felt was correlated with the time of day.

The most compelling evidence turned out to be around fatigue. Among a dozen feelings including “happy,” “competent,” “hassled” and “worried,” “fatigued” was far and away the one most strongly correlated to specific times of day.

Interestingly, most respondents in the study experienced the highest level of negative emotions in the mornings, but also the most energy and the greatest feelings of competence. Energy and competence peaked around noon, and then both declined steadily until bedtime.

In short, the longer subjects were awake, the more fatigued they became and the more incompetent they felt.

But there is an antidote to fatigue and its impact on competence. Not surprisingly, it’s rest. Among 16 potential daily activities — including eating, praying, relaxing and exercising — napping had far and away the biggest impact on reducing fatigue.

So what are the implications for how we ought to work most efficiently?

Here, the work of K. Anders Ericsson, one of the foremost researchers into expert performance, is relevant. In his most well-known study, Mr. Ericsson found that top violinists practice in intense, relatively short intervals, first thing in the morning, for no longer than 90 minutes, followed by a break. They almost never practice more than 4½ hours a day. They also report that practicing is the least enjoyable part of their day.

In short, the best violinists do all of their hardest work in the mornings when they have the most energy and the fewest distractions. In the afternoons, the best violinists regularly take a nap, averaging 20 to 30 minutes. They also report that naps — and sleep — are among the most important things they do to improve as violinists.

Mr. Ericsson studied a sample of just 30 violinists, so his findings are not conclusive. But other researchers have found almost precisely the same practice and renewal patterns among athletes, chess players, artists, scientists and writers.

The lessons for the rest of us are surprisingly simple:

1. Do your most challenging and important work as soon as possible after you wake up, when you have the most energy. (If your highest energy is in the evenings, and you have flexibility, save your hardest work for then.)

2. Focus in the most absorbed way possible when you are working and then take a break at least every 90 minutes to refuel your energy reservoir. Any activity — like deep breathing, reading a novel, talking with a friend or taking a run — can be effective. The key is choosing something you find restorative.

3. Always have lunch, preferably away from your desk.

4. If you can, take a nap no longer than 20 to 30 minutes between 1 and 4 p.m. It will give you a surge of energy — and potential productivity — for the rest of the afternoon. If a nap isn’t possible, simply closing your eyes for a few minutes can still be a source of modest renewal.

I’ve been practicing these steps for more than a decade, and they have transformed both my energy levels and my productivity. Unfortunately, they remain countercultural in the vast majority of organizations. If that’s the case, consider sharing this column with your boss.