A study in the journal Cognition reveals that people can maintain their focus or “vigilance” much longer when their brains are given something else to think about every 20 minutes. That’s the time when thinking becomes less efficient. This trick is called momentary deactivation. If your mind isn’t as sharp after a long period of work, it may not be completely fatigued. It just needs to focus on something else to refresh the specific neural network you’ve been using.

Work with your own circadian rhythms.Are you an early bird or a night owl? Do you fade every afternoon, or is that when you are strongest? Don’t schedule an important meeting at a time when you will be operating on one cylinder. And don’t waste your peak work time at a doctor’s appointment.Relax for 10 minutes every 90 minutes.When you’re awake, your brain cycles from higher alertness (busy beta waves) to lower alertness (alpha waves) every 90 minutes. At that point, you become less able to focus, think clearly, or see the big picture. You know the signals: You feel restless, hungry, and sleepy, and reach for a coffee. Herbert Benson of Harvard, author of The Relaxation Response, recommends working to the point where you stop feeling productive and start feeling stressed. At that moment, disengage. Meditate, do a relaxation exercise, pet a furry animal, go for a quick jog, take a hot shower, pick up your knitting, practice the piano, or look at paintings. Allowing your brain to go into a state of relaxation, daydreaming, and meditating will reset your alertness.

Take power naps.Researchers have found the human ability to learn declines as the day wears on. But an afternoon power nap increases scores on memory tests by 20%.