Stress influences your performance, both on and off the job. The trick is to keep stress under control so that it's a performance booster rather than a performance buster. The figure on the left shows the impact of stress on performance. Numerous studies have shown that when stress is low performance is also low. Performance increases with increasing stress, but only up to the point called the stress/performance (SP) threshold. Once past the SP threshold, performance deteriorates progressively as stress increases. Your stress levels can actually get so high you may have difficulty performing at all.

To make things even more complicated, the SP threshold changes according to how much you have to think to perform a task. Recent research has shown that tasks requiring concentration, integration of information from different sources, and decision making have lower SP thresholds than tasks that require application of acquired knowledge or manual tasks. The figure at right illustrates the fact that it takes less stress to interfere with a manager's performance than it does to interfere with a knowledge or production worker's.