Imagine your brain is a smartphone. Each app you open — answering a question, remembering a name, following a conversation — drains the battery just a little. But with cognitive fatigue, it’s like your phone’s battery never charges past 20%. Even simple tasks can send it into low-power mode. Mental exhaustion can be a daily reality for many people living with a brain tumor.
What is Cognitive Fatigue?
Fatigue is a persistent sense of exhaustion that doesn’t go away with rest, and it can significantly impact one’s ability to perform daily tasks. Due in part to the tumor’s location and/or side effects from treatment or medication, patients may experience physical fatigue, cognitive fatigue, or both.
Cognitive fatigue is mental exhaustion that impacts concentration, memory, and mental sharpness.
What Does Cognitive Fatigue Feel Like?
“Cognitive fatigue feels like my brain and body are working on two separate tracks,” said Carly N., who has glioblastoma. “My brain can’t keep up with my body! I’ll cognitively feel tired mid-sentence, so sometimes I won’t finish my train of thought while in conversation, feel my eyes drop downwards, and want to close. Or if overstimulated and overwhelmed, it’ll give me a big headache, and my brain shuts down.”
Cognitive fatigue impacts people in different ways, but many patients report symptoms like:
- Persistent brain fog
- Memory lapses or forgetfulness
- Trouble finding the right words
- Irritability or increased frustration
- Feeling overwhelmed
- Difficulty concentrating or following conversations
- Frequently losing your train of thought
- Making more frequent mistakes
- Struggling with problem-solving or critical thinking
- Taking longer to complete tasks that require mental effort
“I feel mentally tired, but I often describe it as my mind feels like a dark and cloudy day,” said Tresa Roebuck Spencer*, a former clinical neuropsychologist with recurrent glioblastoma (GBM). “Sometimes it’ll be like the clouds separated and the sun has come back out. When the sun’s back out, I can pick up the phone and call a friend or get on my computer and try to do some work. When it’s cloudy, it’s just harder to think quickly. Everything just feels effortful where it shouldn’t feel hard. Cognitive fatigue feels like I’m just really, really overtired, and my mind is not sharp or thinking quickly.”
What Can Patients Do to Manage Cognitive Fatigue?
While there’s no quick fix for cognitive fatigue, there are strategies that can help you conserve mental energy, reduce frustration, and feel more in control. These practical tips from people living with a brain tumor can make daily life more manageable.
1. Talk to Your Health Care Provider
If you’re struggling with persistent mental fatigue, bring it up during medical appointments. Cognitive fatigue is a real, often overlooked symptom of brain tumors and their treatment.
Your care team may suggest rehabilitation options such as cognitive therapy, speech language therapy, or even medication adjustments to help manage the fatigue and improve cognitive function.
2. Prioritize Tasks and Plan Around Your Energy Levels
Cognitive energy is limited and may fluctuate throughout the day. Learn to schedule demanding tasks like phone calls, paperwork, or important conversations during the times you feel most mentally sharp.
“People will ask me how I can lift barbells, and I share that it’s a different part of the brain,” said Molly M., who has astrocytoma. “Mentally, I have a different kind of tired. By the time the afternoon comes, I’m a different person. That’s why I prioritize talking to people before noon.”
Some patients describe having a finite supply of mental energy each day, so it’s key to be strategic about how and where they spend that energy.
“During recovery, the amount of brain energy I had was very limited,” said Ana H., who was diagnosed with central neurocytoma. “If you asked me to translate at work, it would take twice as long, and I’d need a literal nap after. I would have to go into the dark room for 30 minutes to an hour because my brain will be done for the day. I had to be very intentional about what I said yes to.”
Even everyday tasks can be mentally draining.
“Turning on the TV could take 20 steps,” Ana said. “I’d get frustrated and have to walk away. We don’t realize how much brain power our morning routines take until we’re low on it. Simplify as much as you can out of your morning.”
Other ways to preserve cognitive energy include:
- Break big tasks into smaller steps
- Delegate when possible
- Avoid multitasking and focus on one task at a time
- Say “no” or “not right now” to non-essential commitments
“Even small talk can drain me,” Ana said. “So I streamline what I can and advocate for myself if a task is going to burn me out. If I do this one thing, it might mean I can’t do anything else that day.”
3. Use Routines and Memory Tools
Routines and simple tools can be quite helpful when dealing with cognitive fatigue. Structured habits reduce the mental effort needed to remember what to do and when.
“I used to remember everything, and now I write everything down,” said Julia C., who has a benign brain tumor. “I need to have sticky notes. I need to keep notes in my phone.”
Keeping track of to-dos, appointments, and ideas with reminder apps, calendars, or checklists can ease the cognitive load.
“I definitely had some cognitive issues immediately following treatment,” said Alex E., who was diagnosed with pineal germinoma in college. “My memory was worse than I’d like. I would have conversations with some of my best friends, and I’d forget about them. I would really need to keep lists, or things would just start to slip through the cracks.”
Helpful memory tools can look like:
- Sticky notes in visible places
- Smartphone alarms or voice reminders
- Daily planners or bullet journals
- Medication organizers
- Visual checklists for morning or evening routines
- Designated holding spot for keys, phone, wallet, etc.
4. Look for Ways to Minimize Overstimulation
For many people living with a brain tumor, sensory overload from loud sounds, bright lights, or busy environments can quickly lead to mental exhaustion. Reducing these stimuli can help prevent or lessen cognitive fatigue.
Tresa said, “If I have a lot of noise around me — either a lot of people in my house, or if I’m out at a loud restaurant, or if I go out to the movies — I will experience that cognitive fatigue because I get overstimulated.”
Noisy spaces can make it difficult to concentrate or follow conversations, especially when your brain is already working harder to process everyday tasks.
“It can get quite overwhelming to try to have a conversation with the people [at your table] with all of the background noise at a restaurant,” Tresa said. “We have multiple pairs of earplugs; my husband has them in his pocket, we have them in my car, and we have them in my purse because the noise can get overwhelming and cause cognitive fatigue.”
Conversations can quickly lead to mental exhaustion, so save your mental energy by talking with one or two people at a time instead of in larger group settings.
“I like to tell people that the filter that you’re using to focus on one thing and ignore other things is a little bit less airtight, so the brain is more prone to distraction and fatigue,” said Amy Maguire, MS, CCC-SLP, of the Massachusetts General Hospital Speech Language Pathology Brain Tumor Team. “Instead of having a conversation with three people, maybe just have a conversation with one person at a time and pace yourself. For example, you can avoid a huge gathering of people when you return home from surgery because you’ll probably tap out after 10 minutes.”
You may reduce or prevent overstimulation by doing the following:
- Use noise-canceling headphones or earplugs in loud places
- Wear sunglasses or a hat to reduce bright light exposure
- Choose quiet settings for meals or socializing
- Take breaks in calm, dimly lit environments
- Politely excuse yourself from situations that feel overwhelming
5. Take Breaks
Just like physical fatigue, cognitive fatigue requires rest. Regular mental breaks throughout the day can help you recover from brain fog and prevent further exhaustion.
“I notice when I start to make mistakes, that’s when I’ve hit my cognitive fatigue wall,” Tresa shared. “I start to have trouble doing simple things that weren’t hard to do before, like making a spreadsheet in Excel. When I notice I keep making mistakes, that’s my cue to stop. After 5-15 minutes of shutting down stimulation and letting my mind take a break, that tends to help me, and I can come back to the task I was trying to do and feel fresh.”
Short, intentional pauses can give your brain the reset it needs to function more clearly. This could mean closing your eyes in a quiet room, doing a breathing exercise, or simply sitting still without looking at a screen.
“My favorite advice [my speech therapist has] given me so far was to take ‘brain breaks’ throughout the day,” said Carly. “It’s where you take a couple of minutes to stare off in the distance like you’re daydreaming, but still cognizant of your surroundings. These breaks allow my brain to reset, especially at work, if I’ve been stressed out and overwhelmed.”
6. Reduce Screen Time
These breaks are most effective when they reduce sensory input. Scrolling through social media or watching a fast-paced show may seem relaxing, but for your brain, they still require effort.
“We think things that are pleasant to us are technically rest, but the world is so much more overstimulating than we realize,” Ana shared. “Let’s say we want to take a break at work and sit on our phone and scroll because it’s downtime, and we want to catch up on a few things. For your brain, it’s still really overstimulating.”
Too much screen time can quickly lead to mental exhaustion and overload for those experiencing cognitive fatigue.
“In the beginning, I used to bounce back more quickly, and just would take a short break and move on,” Tresa said. “Now, I find I get cognitively fatigued if I stare at the screen too long. Before, I would have spent eight hours on the computer because of my job. Now I can make it about half an hour to an hour. Sometimes on a bad day, I can only make 15 minutes. When I realize I’m getting tired and my mind is feeling fuzzy, I shut down the computer and switch to something else.”
Even passive screen use, like watching TV, can be overstimulating depending on the content. Shows with fast-paced dialogue, frequent scene changes, or loud soundtracks may make it harder for your brain to rest.
“When I was first released from the hospital, I could only watch ‘Friends’ because it was a show that I watched a million times,” Ana explained. “And if you think about that show, they’re always in the apartment or the coffee shop. There’s no big change of scenery. Nothing big ever happens. There’s no fast action. It’s the same six people. I’d watch it on silent. Anything more stimulating was too much for my brain to handle.”
7. Optimize Sleep
Getting quality sleep isn’t just about feeling rested; it’s essential for cognitive recovery and managing brain fatigue. Sleep and brain function are closely connected, so when you’re not sleeping well, your memory, focus, and mood may be impacted.
“My memory really suffers the most when I’m tired,” Ana shared. “I probably do four or five different things to sleep well. It’s not just how long I sleep; it’s the quality of that sleep that makes the difference in how I function the next day.”
Some ways to improve the quality of your sleep include:
- Sticking to a consistent sleep schedule
- Avoiding screens at least 30–60 minutes before bed
- Creating a calming nighttime routine (e.g., warm bath, light stretching, reading)
- Making your bedroom dark, quiet, and cool
You’re Not Alone in Managing Cognitive Fatigue
Cognitive fatigue can feel invisible, but its impact is real. Whether you’re living with a brain tumor or caring for someone who is, know that mental exhaustion is common, and there are ways to lighten the load.
Small changes, such as simplifying routines, using tools to stay organized, protecting your energy, and prioritizing rest, can make a big difference.
Remember, you don’t have to push through alone. Talk with your care team about what you’re experiencing. Ask friends and family to take on tasks that use up a lot of your mental energy.
If you’re looking for community, connection, or just a space where others get it, join the National Brain Tumor Society’s Brain Tumor Support Conversations. This monthly virtual support group is a safe, welcoming place to share experiences, ask questions, and feel less alone.
* Note: Tresa passed from recurrent glioblastoma after NBTS interviewed her on the topic of fatigue. With her family’s support, we share Tresa’s perspective and tips for managing fatigue in this blog post.
