The Placebo Effect and Exercise: Testing the Mind-Set Matters Hypothesis in an Everyday Context

Abstract

This study aimed to replicate and extend earlier findings relating to potential placebo effects in exercise. Prior research found that when workers were encouraged to view their job as physically demanding they perceived themselves to be getting greater levels of exercise than before, and experienced positive physical health changes despite actual activity levels not changing (Crum & Langer, 2007). These results suggest that expectations play a critical role in the outcomes associated with physical activities, and therefore that health benefits derived from exercise may be due, at least partially, to a placebo effect. In the current study participants (N = 68) were randomised to either the ‘informed’ group (n = 34), who received information on how their current level of housework and gardening qualified as exercise; or the control group (n = 34), who received an equal amount of information on a neutral topic. Perceptions of current exercise participation, and measures of physiological and psychological wellbeing, were taken at baseline and four weeks’ post-intervention. Contrary to hypotheses, both the informed and control groups perceived themselves to be getting more exercise at follow-up. The informed group did not experience significantly greater reductions in weight, body fat percentage or blood pressure than the control at follow-up, nor an increase in positive affect. The current study therefore found no compelling evidence to support earlier research suggesting that changing people’s mind-sets surrounding their current activities will result in meaningful health changes, and therefore no compelling evidence suggesting a placebo effect in exercise.