Introduction: Little is known about people's awareness of the link between insufficient physical activity and increased risk for multiple health outcomes.
Methods: Of 1161 respondents to an online cross-sectional survey of the US population, we randomly selected 361 and used content analysis to code up to three responses to an open-ended question asking what illnesses are caused by insufficient physical activity. Chi-square and Fisher's exact tests examined relations between disease codes and socio-demographics; t-tests and Mann-Whitney U tests examined relations between codes and physical activity intentions and behavior.
Results: Ten codes emerged: cardiovascular (63.5% of participants), metabolic (65.8%), musculoskeletal (10.5%), fatigue (2.0%), psychiatric (8.0%), respiratory (3.4%), gastrointestinal (0.9%), cancer (3.4%), other (2.8%), unexpected interpretation (1.4%). 55.6% of participants named < 3 diseases. Code frequencies were generally similar across demographic groups, ps > .05. Physical activity intentions and behavior were higher among people who either mentioned cardiovascular (pintentions = .001, pbehavior = .001) or metabolic (pintentions = .01, pbehavior = .005) conditions, or who named < 3 diseases (pintentions = .006, pbehavior = .001).
Conclusion: In our socio-demographically diverse sample, awareness of diseases that are associated with insufficient physical activity was largely related to cardiovascular and metabolic problems. Future health communication efforts should raise awareness of the harms of insufficient physical activity for cancer and other diseases.