How Mental Fatigue Can Wreck Your Workouts and Your Race Day Mojo
- Jono Blodgett
- Jul 6
- 4 min read
I like to think of myself as pretty mentally tough. I’ll gladly line up for a challenge, plaster on a determined smile, and dig deep when my muscles start sending SOS signals. But let’s be honest: there are times when it’s neither my quads nor my cardio that wave the white flag, it’s my brain. And if you pretend mental fatigue isn't real, it can quietly gut your best workouts or steal the edge right out from under your race-day shoes.
As Dr. Samuele Marcora, one of the leading researchers in the field, puts it:
“Mental fatigue can have a significant effect on exercise tolerance, even when the muscles are physically capable of more.”
In other words: your brain often decides you’re done before your body truly is.
The Cost of Mental Fatigue
Mental fatigue isn’t just feeling tired or wishing for “just five more minutes” of sleep. It’s the cumulative toll of stress, endless information, and life’s general clutter. Dr. Walter Staiano explains,
“When the brain is loaded with cognitive demands, your perception of effort increases. You feel things are harder—so you stop earlier.”
Suddenly, even the easy days feel uphill, and small tasks seem monumental.
Spartan Races and the Dreaded Memory Obstacle
If you've entered a Spartan race, you know a thing or two about physical challenges. But let me tell you, the memory obstacle stands in a league of its own. Spartan got rid of this obstacle years ago, but imagine you’re six miles in, muddy, sore, heart pounding and that’s when someone hands you a random string of numbers and words to memorize. No big deal when you’re fresh, but try it half-delirious and calf-deep in fatigue. Later in the course, you’re expected to recall it perfectly. Miss a piece? Congratulations, you just earned thirty burpees.
Here’s the twist: just about everyone dreaded this obstacle more than the barbed wire crawls or ice-cold river dips. Why? Because when your body is tired, your cognitive abilities take a hit and the reverse is often true, too. I can’t count the number of times I watched even laser-focused athletes blank out, staring into space as if the answer might be hiding in a distant mountain. I’ve been there, desperately racking my brain for a memory code that might as well be ancient Greek by mile seven. It’s a harsh reminder: physical and mental fatigue play off each other, sometimes hilariously, sometimes humblingly.
How Mental Fatigue Tanks Your Training
It isn’t just race obstacles or burpee penalties. Research consistently shows that mental fatigue “reduces endurance performance and increases perceived exertion,” as Dr. Marcora found in his landmark studies. Here’s what that looks like on the ground:
Motivation? Hard to Find
When your mind is worn out, self-talk loses its spark. Suddenly, “you’ve got this!” sounds about as convincing as spam email.
Focus Falters
Technique-heavy sessions or challenging intervals require attention. But fatigue makes distractions louder and mistakes more likely.
Endurance Fades Sooner
You hit your “I’m done” point faster. Your mind throws in the towel even if your muscles have more in the tank.
This isn’t just a problem for athletes chasing medals; it’s the universal struggle of anyone trying to stick to a fitness routine. Picture this: You’ve spent all day navigating emails, meetings, and the endless grind of to-do lists. You promised yourself you’d hit the gym after work, had the leggings packed, playlist ready, and everything. But then 5 p.m. hits, and the couch starts whispering sweet nothings in your ear. Mental fatigue swoops in like an uninvited guest, and suddenly the idea of peeling yourself off the cushions feels like scaling Everest. That workout? Yeah, it’s now “tomorrow’s problem.”
Mental strain, compounded by stress from news, work, and the digital noise of modern life, raises your cortisol and chips away at recovery and confidence. Dr. John Raglin, a sports psychologist, often points out:
“Psychological stress affects not just mood, but physiological readiness and performance.”
The more fried your brain feels, the more jittery and uncertain you can show up on the starting line—regardless of how well you’ve trained.
Mental Toughness Means Knowing Your Limits
Mental toughness isn’t about ignoring when your brain is tired. It’s being smart enough to recognize when your “grind” mentality is undermining your efforts. Giving your mind a breather is often the bravest, and most strategic, move you can make for your performance.
Taking a Mental Hiatus: Hitting Reset
How do you know it’s time to push pause?
You’re glued to your phone, cycling through social media and feeling drained.
News headlines leave you wired and anxious.
Workouts feel more punishing than rewarding.
Motivation and joy have left the building.
If that sounds familiar, the solution isn’t to double down—it’s to reset.
What helps?
Tech Downtime:
Move your phone out of reach. Hours (or even a weekend) without notifications can work wonders. This is especially important the days leading up to a big race. You don't want to waste mental energy when you should be saving it for decision making during the race.
Swap the Negative for the Positive:
Ditch the doomscrolling for uplifting inputs—nature, music, a non-work book.
Prioritize Sleep:
Lack of rest leaves your brain a mess. Make sleep a non-negotiable.
Try Mindfulness:
Meditation, even in small doses, is backed by science to lower stress and boost cognitive function. Do like I do and get in the sauna!
Learn to Say No:
You don’t need to be everywhere or do everything. Protect your mental bandwidth.
The Benefits of Addressing Mental Fatigue
Once you respect mental fatigue and work to address it, you unlock a new level of resilience. Dr. Staiano notes,
“Recovery is key. Giving your mind time to reset improves both physical and cognitive performance.”
You’ll train with more consistent focus, approach races with a clearer head, and bounce back better when challenges hit.
Bottom line: You can be tough and still care for your mind. Ignoring mental fatigue doesn’t toughen you up, it just leaves you vulnerable to mistakes, burnout, and unexpected burpees.
Listen to your brain. Take a step back when you need to. And next time you hit a memory obstacle, on the course or in life, you’ll be ready for it.
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