Reconceptualizing the measurement of expectations to better understand placebo and nocebo effects in psychological responses to exercise

ABSTRACT

The understanding of placebo and nocebo effects in psychological responses to exercise may be improved by measuring expectations. Despite availability of several validated expectation measures, we argue for using scales that take both positive and negative expectations for exercise-induced changes into account. A cross-sectional survey was used to collect information on positive and negative expectations pertaining to how exercise would affect 14 different outcomes related to psychological health (n = 966). Outcomes for which a majority of the sample (>50%) reported positive expectations for exercise-induced changes included: psychological well-being (75.3%), depression (74.3%), relaxation (74.2%), sleep quality (73.3%), stress (72.2%), anxiety (69.8%), energy (67.1%), and attention (60.2%). Outcomes for which a majority of the sample (>50%) reported a negative expectation for exercise-induced changes were muscle pain (66.3%), fatigue (57.3%), and joint pain (50.7%). Across all 14 outcomes, the percentage of participants with negative expectations for exercise-induced changes ranged from 5.9 to 66.3%. Elucidating the potential presence of placebo and nocebo effects through measurement of expectations may improve the understanding of variability in the direction and magnitude of exercise-related effects on psychological health. Although there were only 3 outcomes for which the majority of participants reported negative expectations, we found that negative expectations were present to some degree for all 14 outcomes. Thus, for researchers who wish to characterize expectations in studies of psychological responses to exercise, we recommend using measures that give equal consideration to positive and negative expectations.

Keywords:

• Cognition
• health
• mood
• physical activity

Acknowledgements

The authors declare that they have no competing interests. The contents do not represent the views of the Department of Veterans Affairs or the United States Government. We would also like to thank the members of the University of Wisconsin–Madison Exercise Psychology Laboratory for assistance with editing the instructions and items that were used in the expectation questionnaire.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Jacob B. Lindheimer http://orcid.org/0000-0002-1581-3210

Attila Szabo http://orcid.org/0000-0003-2788-4304

John S. Raglin http://orcid.org/0000-0002-5298-9514

Chris Beedie http://orcid.org/0000-0003-0106-3479

Kaitlyn E. Carmichael http://orcid.org/0000-0002-9667-8208

Patrick J. O’Connor http://orcid.org/0000-0002-9249-4938

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Jacob Lindheimer was supported by Career Development Award [number IK2 CX001679] from the United States (U.S.) Department of Veterans Affairs Clinical Sciences R&D (CSR&D) Service.