Why the Typical “Work Day” Structure Doesn’t Work For Your Brain

In my works as a productivity coach, one of the most common issues clients bring to me is their perception that they aren’t optimizing their time well enough.

Many report that after a few hours of working at their desks on an engaging cognitive task they flame out. Even after taking a short break to recover, they struggle to get back into the zone.

If you’re in this group, you’re not alone. In fact, I often feel the same way.

Before we get to strategies to help you optimize your day to produce more, it’s important to ask:

Are you being unrealistic in your expectations for how much cognitive work you can do in a day?

Unrealistic Expectations

Your unrealistic expectations did not spring up out of nowhere.

From the time we start school, our culture conditions us to the expectation that our cognitive work is supposed to happen in a basically uninterrupted 8-hour stretch of time. Once we’re done with school life, the block of time from 9–5 that once contained school shifts to work.

Because of this construct, we tend to think of our days as being divided in these big chunks of time. There’s the “work day,” which generally gets defined as the “9–5.” Then there’s the “before work” — the “5 to 9 before the 9 to 5” — and after work, the “after–5.”

The expectation is that once you’re “on the clock,” you’re completely focused on your work tasks with the exception of your “lunch break.”

That approach may work in settings where your work is largely automated, physical, or manual. But it doesn’t work when the work you do is largely cognitive — work that involves thinking, organizing ideas, writing, communicating, or creating.

It doesn’t fit the reality of how the brain works.

The fact that your brain needs a break after a sustained effort of cognitive work isn’t a personal flaw or failing; it’s a feature of the system.

Cognitive Work is a Workout

Think about your physical exercise regimen.

You wouldn’t expect your body to hold up to several hours a day of intense workouts and heavy lifting. For people who exercise regularly, the sweet spot is usually around 60–90 minutes. Even professional athletes who train multiple times a day cap each session at 90 minutes to 2 hours. Then they take a break to refuel and recharge before returning for another training session — which is likely to be something completely different.

You certainly wouldn’t expect yourself to walk around all day holding a dumbbell in the bicep curl position. Your arm would eventually give out.

It helps to think of cognitive work in this frame. After all, your brain is a muscle, and cognitive work fatigues that muscle.

How Sustained Cognitive Work Depletes Your System

In fact, trying to sustain intense cognitive work for hours on end is actually more unnatural than trying to sustain physical movement for hours. Your body is designed for movement and physical activity.

Think about how good it feels to go on a long hike or walk, and how refreshed you feel after, compared to how you feel after sustained brain work.

Studies show that sustained cognitive effort depletes attentional and processing resources. This is especially true for people with ADHD, who start with more limited attention bandwidth. Women in perimenopause, likewise experience a magnified version of this effect thanks to declining estrogen and other hormonal fluctuations.

The sustained cognitive effort doesn’t only create brain fatigue; it also creates physical fatigue.

This isn’t just about “fatigue,” however. Just like lifting heavy weights tears the muscle fibers and creates structural changes in the body, heavy cognitive lifting creates distinct changes in the connectivity and integration of brain networks.

And just like you need to give your sore legs a rest before you do another leg-intensive exercise, you need to give your brain time return baseline before you engage in another heavy cognitive lift.

Crossover Effects of Physical and Cognitive Activity

Physical activity and cognitive activity almost seem to have opposite crossover effects:

An intense physical workout can give you a boost of adrenaline and dopamine that helps hone your focus and attention for cognitive work. If you hit your deadlifts too hard, is you might have sore legs the next day, forcing you to focus on a different part of your body.

But when you push your brain too much at once, it doesn’t just deplete your attention — it can shut down your whole system.

Your Inability to “Push Through” is Not a Personal Failing

The idea that you should push through is both unrealistic and detrimental to your overall health.

Rather than berating ourselves for not meeting unrealistic expectations, we can learn to plan schedules that work with our neurology instead of against it.

I’ll share more about this in the next installment.