Wednesday, February 25, 2009

Mental exhaustion makes workouts harder: study

By Reuters - Tue Feb 24, 3:06 PM PST
CHICAGO (Reuters) - Being mentally exhausted can impair a person's exercise performance, a finding that may help explain why it is sometimes so hard to work out, British researchers said on Tuesday. They said people who did a mentally tiresome task just before exercising reached exhaustion much more quickly than when they had been mentally rested.

Mental fatigue did not affect the performance of the heart or muscles, but it did affect their "perceived effort," Samuele Marcora, Walter Staiano and Victoria Manning of Bangor University in Wales wrote in the Journal of Applied Physiology. "Our study provides experimental evidence that mental fatigue limits exercise tolerance in humans through higher perception of effort," the team wrote. For the study, the researchers had 16 people take a demanding, 90-minute test that required close attention, memory, and left participants feeling tired and listless. Next, they rode a stationary bicycle to exhaustion, while the researchers tracked their heart rate and other vital signs. On a different day, the same group simply watched a 90-minute documentary film before riding the bike. The researchers found participants stopped exercising 15 percent earlier on average when they were mentally exhausted, even though there was little difference in their cardio respiratory or muscle function. "It provides strong evidence that brain function can limit short-term endurance performance," the team wrote. The researchers said the next step is to look at the brain to find out exactly why people with mental fatigue perceive exercise to be more difficult.
Interesting study. I wonder if the authors wrote this article before or after exercising.

Q1: Does this mean that poor exercise performance can be "all in our heads?"

Q2: Is any other performance decreased due to mental fatigue, such as work or parenting?

I believe the answers are yes, yes and yes, but, a better question would be:

How do we get past the mental fatigue and continue to perform optimally?

As it pertains to exercise, Andy Dick of Optimal Fitness, has the following thoughts on getting past the exhaustion, or as some athletes call it, "getting past the wall".

I believe that this research points out an important point. You can (and should) only focus on so much without breaking down in one aspect or the other. Just like multi-tasking and juggling too many things at work can lead to reduced production in all of your work goals, exercise can suffer as a result of a long day at work. If one can focus on exercise as a method to relieve the day’s stress rather than as a an all-out He-Man workout, it can and should help break up the tightness in your mood. Rather than skipping the workout, re-focus on why you hit the gym!

Andy Dick
Owner, Optimum Results
(609) 304-7598

Check out Optimum Results - Personal Training for this month's healthy tip!

Thanks Andy!!

As I mentioned earlier, I believe mental fatigue, or as we should call it "STRESS", decreases our performance in many daily activities which then leads to phrases like "I woulda, I coulda and I shoulda." These phrases only perpetuate the stress and do not help in finding a way to release it.

My favorite stress release methods include reading a favorite book or magazine, or cooking a favorite meal, low carb of course ; )

If you have any favorite methods to reduce your mental fatigue, please visit my blog and post your annonymous methods in the comments section. This is where I hope we can all learn from each other. And I hope they are better than this next cartoon.

Steven Horvitz, D.O.
Board Certified Family Medicine
Founder of The Institute for Medical Wellness


  1. Anonymous10:06 AM

    I find when I'm mentaly exhausted and not into a workout I tell myself "ok just 10 minutes". Then after 10 minutes I can usually go "ok 10 more". By the time I'm finished with all the "10 mores" I've gotten 30+ minutes in. Focus only on the 10 minutes and the stress of a 30+ minute workout is easier to handle. By the time I'm finished my stress is reduced and I can handle everything better. Especially MY ATTITUDE.

  2. That is a good point. Shorten your goals into something attainable, instead of something that is a set up for failure. Once you complete the shortened goal, your attitude may improve and you can shoot for higher goals.

    Does anyone have any other non-exercise related stress relievers they can share?

  3. Anonymous11:56 PM

    I do a Spa Works! Program (mobile spa business) as my home business. I find that if I follow my own teaching/advice it makes things easier. I'll put on some relaxing music, do a foot soak or foot wrap, cool towel on my eyes and relaxation breathing. Trying to keep my inhale and exhale the same. Each time I exhale I visualize that I'm pushing all the stress out of my body. When I catch myself going back to "thinking about the stress" I start focusing on the breathing again.