Surprising link between exercise and negative memory bias discovered

Exercise is typically known for its positive mental health effects and even as effective as antidepressant medication or psychological treatment in reducing depressive symptoms. But in an attempt to understand how exercise improves depression, researcher, Michele Schmitter, discovered that exercise can exacerbate the tendency to recall negative as opposed to positive material among those who engage in high levels of rumination.

The research group of the Radboudumc, Department of Psychiatry, led by Janna Vrijsen, published the results in the Journal of Cognitive Behaviour Therapy in February, 2023. They conducted an experimental study where healthy participants were invited to the lab. To induce a depressive mood state, participants first saw a segment of a sad movie, then they either exercised at moderate-intensity or rested for 30min. Afterwards, the researchers measured depressotypic cognitions such as a negatively biased memory or rumination. 

Surprisingly, the exercise condition recalled more negative as opposed to positive material among those who engage in high levels of rumination, while at the same time experiencing more positive affect. No differences were found in other depressotypic cognitions or negative affect. Therefore, it seems that a single exercise bout is not sufficient to improve depressive cognition and can even aggravate negatively biased memories in some individuals. 

One explanation for this finding is that individuals prone to ruminate may have experienced the exercise session as stressful. Exercising was not voluntary initiated and may be very different from usual exercise activities such as going for a run in nature. Especially being monitored during the session and being required to keep the right intensity level might have been experienced as stressful. Accordingly, the researchers have already set up a secondary study to examine the effect of exercise on deperssotypic cognitions in the naturalistic environment.

Publication

Schmitter, M., Vanderhasselt, M. A., Spijker, J., Smits, J. A., & Vrijsen, J. N. (2023). Working it out: can an acute exercise bout alleviate memory bias, rumination and negative mood? Cognitive Behaviour Therapy, 1-14.