Cardiorespiratory fitness, physical activity level, and chronic pain: Are men more affected than women?

Objective: To evaluate the cardiorespiratory endurance (CRE) and physical a ctivity level of patients with chronic pain compared with healthy subjects. Design and Subjects: Cross-sectional study, with a consecutive sample of 55 patients with chronic pain (20 men, 35 women). Comparison of CRE and physi cal activity indices obtained in patients with data available in the litera ture for age-matched healthy subjects. Setting: A multidisciplinary pain center in a city of more than 1.000,000 i nhabitants. Outcome Measures: A physical working capacity index (PWC65%/kg) and physica l activity level scores and subscores obtained with two questionnaires (the Baecke and the Five-City Project questionnaires). Results: The physiological gender difference in CRE indices that characteri zes healthy subjects was not observed in patients with chronic pain. When c ompared with values previously obtained in controls, male patients presente d with a very significant 34% reduction in PWC65%/kg. The 17% reduction fou nd in women hardly reached significance level. The Baecke total physical ac tivity score was significantly higher in female than in male patients, a fi nding not observed in healthy controls. There was no significant difference between male and female patients in the Five-City Project total physical a ctivity score expressed in kilocalories per day per kilogram (i.e., normali zed for body weight), although data from the literature show that healthy m en present with a significantly higher level of physical activity compared with healthy women. Conclusions: Data on CRE and the physical activity level of patients with c hronic pain obtained in this study show that chronic pain may have a greate r impact on male than female patients. Sociocultural factors are probably a t the origin of this phenomenon.