Affective forecasting error in exercise: Differences between physically active and inactive individuals

The tendency to underestimate how enjoyable exercise will be-an affective forecastingerror-is thought to undermine motivation for regular physical activity. We sought toclarify limitations of previous work by examining whether (a) physically inactive individualsshow the same forecasting error as physically active individuals, and (b) experiencedenjoyment mediates the relation between expected enjoyment and intentions, and whetherphysical activity levels moderate this relation. Prior to a 30-min workout, physicallyinactive (<60 min of physical activity/week; N = 18) and active (≥150 min of physicalactivity/week; N = 24) individuals reported their expected enjoyment. Afterward, theyreported experienced enjoyment and exercise intentions. We found a marginally significantinteraction (p = .07, partial η² = .08) between group (active, inactive) and time (expected,experienced enjoyment), suggesting the forecasting error differed for active and inactiveindividuals. Specifically, inactive individuals reported significantly lower expected enjoymentthan active individuals (p = .02, d = .73), but reported similar levels of experienced enjoyment (p = .27). We also found that experienced enjoyment mediated the relationbetween expected enjoyment and exercise intentions for inactive (ab = .367, 95% confidenceinterval [CI]=.075, .742) but not active individuals (ab = -.079, 95% CI = -.269,.089). The findings suggest that lower expectations for exercise enjoyment characterizephysically inactive individuals and provide support for the conclusion that the affectiveforecasting error undermines motivation for regular physical activity. However, amonginactive individuals, experienced enjoyment had a stronger relation with intentions toexercise regularly than expected enjoyment.