There is plenty of research available reporting the beneficial effects of exercise on mental performance. Rarely do we find a study that examines the opposite. How does mental stress affect our workouts, does mental stress have a negative effect on our workouts?
The answer is YES! A study published in the Journal of Applied Physiology (2009; 106,857-64). Participants were asked to ride a stationary bicycle to fatigue after completing two tasks: a 90 minute computer task and viewing train and automobile documentaries. During the exercise bouts the researchers measured oxygen consumption, heart rate, cardiac output, blood pressure, ventilation and blood lactate levels. Perceived exertion and motivation level were also measured.
The study found that subjects stopped exercising 15% earlier when mentally stressed. The participants stopped exercising at the same point of perceived exertion. When mentally fatigued a greater level of exertion was perceived and exercise was discontinued. Nonfatigued exercisers achieved a higher heart rate and blood lactate levels, most likely do to a longer exercise session.
This study does provide us with proof that stress negatively affects our exercise performance through a higher perception of effort.
Take home message- get your workout in before the stress of the day starts!