It’s 2:00 p.m. (…ish. You’re too tired to process the exact minute.) A coworker walks by you with a sandwich from the cafeteria. Is that coffee? You know you smell coffee. You look at the clock and, like Peter’s character in the movie Office Space, you realize all of two minutes have gone by. How can that be?! You’ve been working for an eternity. You need coffee.

 

Such is the story of the familiar afternoon slump. And like many workers in the United States, you might feel pressured to ignore your drowsiness and just keep working. But don’t do it! Your brain is sending you an urgent message you can’t afford to neglect.

 

The Ultradian rhythm

 

You probably know about your Circadian rhythm, which is a biological system that controls your sleep/wake cycle over 24 hours. But you have biological cycles that are shorter than 24 hours, too. These are ultradian rhythms.

 

Utradian rhythms have been made famous primarily through sleep study. The “father of sleep”, sleep researcher Nathaniel Kleitman, figured out that people go through ultradian cycles whenever they get some shuteye. It was Kleitman who discovered rapid eye movement (REM) and proposed that sleep included active brain processes. But Kleitman also discovered that a Basic Rest Activity Cycle (BRAC) is present when people are awake, too. Generally, these daily ultradian cycles involve alternating periods of high-frequency brain activity (about 90 minutes) followed by lower-frequency brain activity (about 20 minutes). Scientists think that it’s a delicate balance of potassium and sodium that ultimately controls these cycles. They also know that brain cells use sodium and potassium ions for electrical signals, and that your sodium and potassium levels are involved in the osmosis process that transports other chemicals in and out of your brain cells.

 

Now, here’s where it gets cool (and important for your work).

 

The brain is kind of a resource hog. It uses more energy than any other organ in the body, draining up to 20 percent of the fuel you have available. Most of that energy (about two thirds) is spent getting nerve cells to fire, with the rest spent in cell maintenance. When you work really hard, are alert and your brain is functioning in high brain wave states, you eventually disrupt the sodium/potassium balance. The brain detects this and downshifts, moving toward lower brain wave frequencies for a break. You perceive this as a general fogginess, fatigue or inability to concentrate. Once your brain has had time to get itself together, restoring the sodium-potassium ratio back to normal in the Theta state, the haze passes and you’re ready to charge at your work again.

 

The result of ignoring your natural cycles

 

But what happens if you try to push through the rest phase of your ultradian rhythm? You trigger your body’s fight-or-flight (stress) response. That’s bad news because, as part of your natural survival mechanisms, the fight-or-flight response causes the parts of your brain that handle logic to become less active, the idea being that, if you think completely through a threat, you’ll probably end up getting creamed. You lose the ability to focus, and you’re hyper alert and anxious.

 

The result isn’t pretty. Health Advocate, Inc. asserts that presenteeism–being on the job but not functioning up to capability–costs $150 billion annually in lost productivity. It also says that 60 percent of surveyed workers admitted losing productivity due to stress while at work in the past month. Additionally, Rebecca Maxon of Fairleigh Dickinson University asserts that, more generally, stress costs American companies an estimated $200 billion every year. The American Institute of Stress places that estimate even higher at $300 billion. Not all workplace stress is related to not getting a break, of course, but the figures quantify the need for workers to relax and recharge where they can, and to be more aware of the stress sources that might be less immediately obvious.

 

How to tune in

 

It might be difficult to fight the cultural constructs that push you and others to ignore the physical signals associated with your ultradian rhythm–fully 90 percent of workers don’t take any defined break through the day, caving to the pressure to trade time for money. But ideally, when you start to feel your focus draining due to your ultradian rhythm, crash and take a nap. There are specific productivity and cognitive benefits based on how long you sleep, but 10 to 20 minutes (about the length of the lull in your ultradian rhythm) is ideal for alertness. But if you can’t do that, the next best thing is to set your work aside and shift your attention to something less demanding. Make a lap through your building (or better yet, around it), kick back in your chair with some relaxing music you like, turn away from your desk with a snack or do anything else you enjoy that winds you down. Apps can make your screens inaccessible temporarily or remind you to rest your eyes, too. Just pay attention to your body and work with it. The rewards might surprise you.