Mental fatigue can affect physical endurance

Findings could become research model to help those with chronic fatigue

Mentally tired individuals will reach exhaustion quicker that those who are not mentally fatigued according to findings of a study by Bangor University.

In the trial conducted by exercise physiologists at the University's School of Sport, Health & Exercise Sciences, participants who performed a mentally fatiguing task prior to a difficult exercise test, reached exhaustion more quickly than when they did the same exercise when mentally rested.

The study also found that mental fatigue did not cause the heart or muscles to perform any differently. Instead, our “perceived effort” determines when we reach exhaustion. 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.

Dr. Samuele Marcora, and Post-graduate students Walter Staiano and Victoria Manning's results will appear in the March print edition of the The American Physiological Society's Journal of Applied Physiology.

"This research could provide a way to study chronic fatigue syndrome," Dr. Marcora said. "People with chronic fatigue report that they lack energy and experience “brain fog,” just like the mentally fatigued participants in this study. In addition, as in this study, people with chronic fatigue perceive exercise to be more difficult despite physiological responses considered normal during exercise.

"The research model may also be helpful for military personnel. They do physically demanding tasks after long period of vigilance. Vigilance produces mental fatigue.

"Finally, our study suggests that people doing high intensity training, such as competitive athletes, should do their training while mentally rested. However, people who exercise after work should continue doing so, even if mentally fatigued. Most people work out at a moderate intensity, which still gives plenty of physiological and psychological benefit, including relief from stress and improved mental performance."