Jon Johnston

Neurofatigue — How Mental Energy Is Like Water Conservation

You desperately need to conserve it

There was a time in my life when simple tasks weren’t a problem. They were simple, hence the meaning of the word. Calculating a 20% tip at a restaurant wasn’t rocket science. It was easy. I quickly did the math in my head, paid the receipt and went on my way.

That’s changed since I had a heart attack in August 2015, that left me dead for over 20 minutes. Being down that long caused a traumatic brain injury (TBI), the effects of which I will deal with the rest of my life. Six years since, I’m still trying to recover as much of my life as possible.

Back to the restaurant. I try to calculate the tip, then I stare at the numbers on the receipt. I do it again because I don’t trust the total. I’ve resorted to using the calculator on my phone only to hear comments that I’m too stupid to do simple math. It’s easier to hand the receipt to my wife and have her do it. Then I hear comments about being lazy (although not from my wife, she understands what I’ve been through).

It’s clear whatever part of my brain that does math is damaged. I graduated from college with a math minor. Pre-brain injury, I enjoyed reading articles about advanced analytics in sports. I understood investing charts. Converting tablespoons to teaspoons was a breeze.

Post brain injury, I avoid math. Trying to understand a scatterplot graph can exhaust me in as little as 10 minutes and take my chronic headache pain from a two to an eight. I become irritable. I snap at people.

What Is Neurofatigue?

Every brain injury is unique, but one commonality amongst TBI survivors is mental fatigue, sometimes referred to as neurofatigue. Neurofatigue is a lack of mental energy. Neurofatigue doesn’t sound awful until you realize it affects everything you do. Math is especially detrimental to me, but simple tasks such as talking to my family, attending a Zoom meeting, or trying to understand the dialogue during a movie drain mental energy like water pouring down a drain.

Neurofatigue is also called “brain fog”. You cannot concentrate. Simple tasks take forever to complete. You get lost in what you’re doing, such as re-reading the same paragraph of a book over and over.

TBI survivors have a hard time getting other people to understand neurofatigue. If I try to tell someone about it, I frequently hear them respond that they, too, get tired while working. This isn’t the same. Everyone gets worn out from working. What I’m talking about is having your life sucked dry within minutes by some stupid menial task that a five-year-old child could complete in a few seconds, then happily carry on with their lives as if it were a breeze.

This isn’t because I’m old. It isn’t because my job is difficult. It isn’t because of stress. It’s because my brain is damaged. I’ve tried to come up with analogies to explain the problems caused by my TBI. I’ve come up with “warehouse theory” so other people could understand why my memory is so fractured.

Mental Energy As Water

Now I’m going to use a water usage analogy to explain neurofatige. According to the EPA, Americans consume an average of 82 gallons of water per day at home.

People take freshwater for granted. We turn on a faucet and there it is, readily available. We wash our clothes, flush a toilet, or water our lawn without a care as to how many gallons of freshwater we consume. We pay little attention to how much we use because water is always available. (This isn’t always true, such as during water restrictions in a drought, but please just run with it.)
For this analogy, you are limited to 20 gallons of water per day. Old toilets made before 1982 consume 5 to 7 gallons per flush. Newer toilets consume 1.6 gallons per flush. Washing your clothes can take 25–45 gallons of water, dependent upon what type of washing machine you use. An average shower uses 2.5 gallons per minute, so an eight-minute shower will consume your daily water allotment (if I’ve done the math right). These are common daily tasks. When you’re limited to 20 gallons per day, you can see there will be problems.

If you run out of water, you will have none to drink. You can’t wash your dishes, your clothes, yourself, water your lawn, feed your pets, or flush your toilet. You might consider all these necessities, but if you had to live without them, you’d conserve.

You’d be forced to spread them out. You might not shower every day. You wouldn’t run the water when brushing your teeth. You’d be more careful when rinsing dishes. You might not flush the toilet every time you use it, preferring to follow the (hippy) water conservationists’ phrase, “If it’s yellow, let it mellow. If it’s brown, flush it down.” While that might sound disgusting, you don’t get a choice. You are severely limited in water usage and must make hard choices, no matter how difficult they sound.

You will become a dehydrated, smelly, unkempt menace to society with a terrible lawn unless you figure out how to manage your water usage. Your friends will avoid you. Your neighbors will call the association about your crappy lawn. Your family will leave you in search of more water. Your life will dissolve around you.

Photo by Paul Meckes on Unsplash

This type of conservation is forced when you have a brain injury. Daily work tasks consume energy. Anything that involves stress magnifies the consumption of energy as if you were performing a chore with a refrigerator strapped to your back. Having an argument, even a simple argument, with a co-worker or spouse can suck my energy dry in a matter of a couple of minutes.

Like water conservation, you are forced to deal with the bare necessities of life. You’re forced to make choices you wouldn’t have otherwise to conserve your mental energy. I walk away from confrontation as much as possible. I try to avoid conversations about religion or politics unless I know the person I’m discussing these subjects with isn’t going to become unhinged if I disagree with them. I ignore or avoid whatever isn’t specifically important to me, all to keep from running out of mental energy, the same way you would try to avoid running out of water.

You’re done when you run out of mental energy. Life stops. You can’t function anymore. It doesn’t matter where you are or what you’re doing. You might be in the middle of grocery shopping and become disoriented, forget your list, and wander around the store trying to remember why you came there in the first place.


Much like water, TBI survivors can replenish mental energy by letting the tank refill. This is done by taking a break — by resting the brain. “Rest” means doing nothing. It doesn’t mean switching from a mentally challenging activity to another, which still requires mental processing. It means doing just that — doing nothing.

You do nothing by practicing mindfulness. You can meditate. You can try one of my personal favorites — the 10-minute nap. There are countless apps available to assist you; Calm, Headspace, Happify, to name a few. Guided meditation videos on Youtube abound. Trying any of these to see if they can help with neurofatigue requires only an open mind and patience. YouTube is free while the apps offer trials.

What TBI Survivors Need

TBI survivors face neurofatigue daily. We have to understand how to properly use what mental energy we have so we don’t run out and find ourselves abandoned in the produce section at Target. We know we’re slow. We know we look tired. We know sometimes we sound like we’re drunk when we’re not. You don’t need to tell us.

What we need is for you to understand is neurofatigue isn’t the same as you being tired after attempting to complete the New York Times crossword puzzle. We need you to not push us to do more when we can’t. We need time to replenish.

And maybe a glass a water.