Relationship over time between psychological distress and physical activity in colorectal cancer survivors

Increased physical activity in patients with colorectal cancer is related to improved recurrence-free and overall survival. Psychological distress after cancer may place patients at risk of reduced physical activity, but paradoxically may also act as a motivator for lifestyle change. The relationship between psychological distress and physical activity after cancer over time has not been described.

A prospective survey of 1,966 (57% response) colorectal cancer survivors assessed the psychological distress variables of anxiety, depression, somatization, and cancer threat appraisal as predictors of physical activity at 5, 12, 24, and 36 months postdiagnosis; 978 respondents had valid data for all time points.

Higher somatization was associated with greater physical inactivity (relative risk ratio [RRR] = 1.12; 95% CI, 1.1 to 1.2) and insufficient physical activity (RRR = 1.05; 95% CI, 0.90 to 1.0). Respondents with a more positive appraisal of their cancer were significantly (P = .031) less likely to be inactive (RRR = 0.95; 95% CI, 0.90 to 1.0) or insufficiently active (RRR = 0.96). Fatigued and obese respondents and current smokers were more inactive. Respondents whose somatization increased between two time periods were less likely to increase their physical activity over the same period (P < .001). Respondents with higher anxiety at one time period were less likely to have increased their activity at the next assessment (P = .004). There was no association between depression and physical activity.

Cancer survivors who experience somatization and anxiety are at greater risk of physical inactivity. The lack of a clear relationship between higher psychological distress and increasing physical activity argues against distress as a motivator to exercise in these patients.