Working hard when fatigued could be harmful to one's health, according to new research by psychologists at the University of Alabama at Birmingham, USA.
The research supports a theory which suggests that exhausted individuals' cardiovascular systems are forced to work harder when they attempt to complete tasks, such as those encountered on the job or at school.
The research, published in the July issue of the International Journal of Psychophysiology, found that fatigued individuals had larger blood pressure increases than rested individuals under conditions where they viewed success as both possible and worthwhile.
When fatigued individuals perceive a task as achievable and worth doing, they increase their effort to make up for their diminished capability due to fatigue. As a result, blood pressure tends to rise and remain elevated until the task is completed or individuals stop trying because they think success is impossible or too difficult to be justified.
"Individuals who experience chronically exaggerated cardiovascular responses are believed to be at greater health risk than individuals who do not. Thus, the implication is that chronic fatigue may pose a health risk under some performance conditions," said UAB psychologist Rex Wright, who led the study.
"It might be argued that fatigue is of little concern from a health standpoint because people will tend to withdraw effort once they become fatigued. The problem with this view is that it fails to recognise that people do not always have the luxury of withdrawing effort or perhaps the wisdom to do so."