Nudging people off of the couch. A nudge experiment on physical exercise in collaboration with SATS.

Abstract

In this paper we demonstrate that it is possible to increase average weekly exercise frequency by up to 9.45%, by sending the study participants e-mails. Several of the leading causes of death globally are closely linked to physical inactivity. In fact, more people die from coronary heart disease than from starvation every year. Exercise can mitigate the risks of these diseases and increase general health. We consider exercise as an intertemporal choice in the context of the Hyperbolic discounting model. To increase exercise frequency we perform a natural field experiment with the Nordic gym chain SATS, where we send three different types of e-mails to three randomized treatment groups over nine weeks. We then compare the treatments to a randomized control group with a difference-in-differences approach. The results show a difference in magnitudes in coefficients for the three different treatments, indicating that the textual contents of the e-mails matter for treatment outcome. This thesis contributes to the body of literature by including very large sample sizes compared to previous studies within the field, and furthermore, by having a completely randomized sample and not having any self selection into the study.