For years, achievers have tried to crack the productivity code. The idea of getting more done in less time is a seductive one. With so many tasks competing for our attention, how could we not love the idea of getting a handle on the never-ending to-do list? I am the queen of the 15-minute call — my philosophy is that 75 percent of meetings can be had in a 15-minute call. This technique allows me to get a lot done and connect with many people without having calls and meetings drain my day. Still, I’m always looking for the next productivity hack.

Here’s a secret of highly productive entrepreneurs and creatives: they respect their ultradian rhythm. You’re probably familiar with the term circadian rhythm, which describes the cycles of waking and sleeping periods. Ultradian rhythm refers to recurrent physical cycles within a 24-hour period. These cycles include blinking, urination, heart rate, and hormonal release. It also extends to the high and low tides of your energy levels. Focusing on your ultradian rhythm is an untapped yet powerful way to work with your body’s natural tides of energy and get more done.

Energy management expert Tony Schwartz recommends working in 30-90 minute intervals and resting or doing something unrelated for a short period before returning to another 30-90 minute sprint. I personally use this method and it works extremely well. Its effectiveness stems from the fact that your mind can be completely centered on one task when you know that a break is coming.

Plus, there is a diminishing marginal return on the investment of attention and time. You may have experienced this if you’ve hunkered down to work on something for hours and you slowly notice your focus dissipating and your energy levels declining. Breaks are a key aspect of productivity. Some people use their breaks to nap while others can surf the web for a bit to clear their mental palate. The most important thing is that you give your brain a rest for 10-15 minutes before diving back in.

Here’s how to uncover your ultradian rhythm:

1. Note your energy levels
Do you know when your golden time is? It’s the time of day when you have the most focus and mental clarity. It also tends to be the time of day that you’re most effective. Time seems to slow down, and you can blow through important tasks. The easiest way to discover your golden time is to create a time journal for a week. Note how you feel each hour and what you’re working on. After a week, review the journal and note any patterns. Do you feel more energy before 9 a.m. or after 10 p.m.? Is writing easier in the afternoon than the morning? Use the data to assess when you’re most effective and mold your schedule around your golden times.

2. Experiment
Try working from home for an entire week. Explore what happens when you schedule all of your calls in a single day instead of spreading them out over the week. Try breaking tasks into 90-minute chunks for a few days. Your productivity revelations won’t come down from the heavens. The more you experiment, the sooner you’ll uncover how to master your ultradian rhythm.

3. Try a nap
Thomas Edison noted the importance of naps as he pursued thousands of inventions. Other historical figures such as Winston Churchill and John F. Kennedy are known nappers. The nap doesn’t have to be long — just 15 minutes can be a big difference in your energy levels. Tony Schwartz recommends taking naps every day in the afternoon. Give it a try and see how it affects your energy levels.

Productivity is about more than getting things done. It’s also about maximizing your enjoyment and satisfaction during working hours. Now you’ve got a new tool to for managing your daily tasks.

This post originally appeared on the author’s blog.