If you didn’t know by now, the mind plays a powerful role in our ability to do high level physical work over a long period of time.

For instance, researchers found that after performing cognitively demanding tasks for longer than 30 minutes prior to a performance test, cyclists reached exhaustion 15% quicker.  Not limited to cyclical aerobic efforts, when subjects in another study performed longer duration knee extensor submaximal isometric contractions in a mentally fatigued condition, their arrival to exhaustion occurred 13% quicker.

What’s the take away?  Mental fatigue decreases endurance performance.

But how does this occur?  Is prolonging the arrival of exhaustion a mental skill that can be trained?  Does mental fatigue affect only endurance?  What about strength and power?

I answer those questions and come up with a host of solutions to help you train your brain to fight off fatigue longer and subsequently improve your endurance.

How Mental Fatigue Works

Performance in endurance events is largely a result of the athlete’s level of drive, or willingness to do work.  Drive is impacted in two ways

  1. The perception of the effort’s difficulty.
  2. The potential reward for the effort.

Tasks involving prolonged attention, memory, and response inhibition are effective in triggering mental fatigue.  High pressure practice session, long days at work, or sport competitions are also effective.

Studies show that mental fatigue decreases drive by increasing the perception of the effort required for the activity.  Higher perceived effort for a given task decreases the willingness to continue working.  Interestingly, mental fatigue has no impact on traditional limiters of endurance performance, such as heart rate, the buildup of lactate, and neuromuscular fatigue.

While not entirely proven, researchers believe that mental fatigue accumulates when levels of the neuromodulator adenosine accumulate in the brain after cognitively demanding tasks lasting over thirty minutes.

How to Limit the Impacts of Mental Fatigue on Endurance Performance

So how do we improve our ability to handle the impacts of mental fatigue on our endurance performance?

1.  Sleep more and better.  Studies show that sleep deprivation increases the amount of adenosine in the brain similar to levels following a cognitively demanding task.   8-9 hours of sleep a night is optimal.

2.  Set clear goals for your session/competition.  Having a better understanding of the training session’s or competitions objectives will improve your ability to push longer into fatigue.   Are you training/racing/testing to be your best or be the best?  Are you attaching realistic expectations to your performance?  Both of these ideas target your motivation i.e. your potential reward for your effort.

3.  Practice training in a mentally fatigued state.   Frequent exertion of activities that develop self-control, whether by performing a mentally challenging activity like the Stroop Test or by participating regularly in effortful physical activity, can ‘train’ or improve self-control, which becomes strained by cognitively taxing activities.  Better self control translates directly to your ability to set pace, a decision making skill that allocates how much energy is allocated to the effort at each given moment of the session/competition. Out of the studies reviewed, researchers argue that a minimum of thirty minutes of mentally taxing work should proceed endurance activities in order to train the body in a mentally fatigued state.

4. Develop positive self-talk strategies.  When the sh*t hits the fan as it inevitably will do in the later stages of a long endurance activity, you better have some mantras to which you turn to support you through the rough patches.  “Breathe”, “I am strong”, “I’ve worked hard and I’m prepared”, “I can do this” are a few positive self talk phrases you can return to to make sure you stave off the negative energy that saps performance.

5.Drink coffee.  Hooray!  Yes, for all of you java heads out there, coffee fights mental fatigue and boosts endurance performance.  An antagonist to adenosine, caffeine increases neurotransmitter activity which increases arousal and excitability, reducing the perception of difficulty of effort.

One more fun fact about mental fatigue:  studies show that it does not limit strength, speed, or power.  Good news for all you strength and power athletes out there!

Mental fatigue is a limiter to endurance performance, but with the right strategies and training you can reduce the harmful impacts of mental fatigue on your performance.

Works Cited
Mental Fatigue Impairs Endurance Performance: A Physiological Explanation.  Martin, Meussen, et.al.  Sports Medicine (2018) 48:2041–2051

Drive in Sports: How Mental Fatigue Affects Endurance Performance.  Schiphof-Godart, Roelands, and Hettinga. Frontiers in Psychology (2018). Vol 9 Article 1383.

Drive in Sports: How Mental Fatigue Affects Endurance Performance.  Pageaux and Lepers. (2018). Ch 16: 291-315.