After a busy day at the office, many people collapse onto the sofa instead of getting some exercise. The mechanism behind this phenomenon is what Sven van As explored in his Ph.D. thesis, which he is defending at Radboud University on November 2. “When we feel stressed or tired, we tend to go for the easy option.”
Contrary to expectations, Sven van As’s Ph.D. research did not provide evidence that cognitively demanding work leads to lower levels of physical activity. What he did observe is that people are more likely to exercise if doing so doesn’t cost too much effort, and the activity is fun enough.
Path of least resistance
“As humans, we have a natural tendency to physically exert ourselves as little as possible,” explains the psychologist.
“If we have a car at our disposal to do our shopping, we’re likely to leave our bicycle in the shed, especially when we’re tired or stressed. These kinds of automatic processes were useful in earlier times because they helped us to conserve energy, but now they can work against us. Earlier research has shown that people tend to exercise less after a demanding day at work, especially in stressful office jobs with high work pressure and little autonomy. I wanted to better understand the psychology behind this phenomenon.”
Simulated office work
In a first sub-study, Van As asked more than 1,000 office employees who spent more than five hours a day doing computer work to complete a questionnaire, and to do so again one year later. The results showed that the higher the demands on employees, the more tired they felt, and the less physically active they were in their free time.
The researcher also ran some experiments with students. Test subjects were invited to complete easy or difficult office tasks, following which they were repeatedly (60 to 125 times) asked to choose whether or not to engage in a physical activity. In the first experimental study, the options always included a physical and a non-physical activity, based on how much the participant enjoyed these activities. In the second study, the level of physical exertion required by the task varied, as did the reward level. In this way, Van As could accurately map the decision process underlying a subject’s choice to exercise or not.
The study did not provide any evidence that the task demands of office work determined whether students opted for a physical activity. Their choice depended mostly on how much the students enjoyed the physical activity, how much effort it required, and the reward they would get for it.
Still, according to Van As, this does not mean that there is no correlation between cognitively demanding work and lower levels of physical activity. “In the lab, we had students complete tasks that may have been cognitively demanding, but not particularly stressful, and of rather short duration. In a follow-up study, we could look more closely at real-life work situations, or simulate a work setting in which heavier tasks really do lead to more fatigue than lighter ones.”
To predict a person’s willingness to engage in physical activity, it seems important to look at the balance between the effort required for an activity and the reward. This is a valuable insight, says Van As, especially in view of the National Prevention Agreement. “If you find it hard to get moving, it might be a good idea to look for physical activities that you really enjoy, and have an alternative at hand that is less demanding, such as walking instead of running. That way, you increase the chances that you will start moving, and keep moving.”