The relationship between moderate to vigorous physical activity and cognitive rigidity in anorexia nervosa.

A drive for physical activity despite underweight is a core feature of anorexia nervosa. This pilot study detects which aspect of physical activity, if any, could be related to cognitive rigidity in anorexia nervosa. Twenty-eight outpatients with anorexia nervosa and 24 healthy participants were assessed for cognitive flexibility with the Trail Making Test (TMT) and for multiple dimensions of physical activity by subjective and objective assessments. Correlation analysis was conducted to disentangle the relationship between cognitive rigidity and the different aspects of physical activity, then, the moderating effect of anorexia nervosa on this relationship was assessed. A principal component analysis was performed to incorporate all variables of physical activity in (a) global factor(s) reflecting the multidimensional nature of this construct. Cognitive rigidity (TMT b - a score) was significantly correlated to the amount of objectively assessed physical activity estimated, only in the sample of patients with anorexia nervosa. The principal component analysis confirms the correlation between a single construct of "physical activity" and cognitive rigidity in anorexia nervosa only. This pilot study suggests a relationship between cognitive rigidity and physical activity that could help explain the persistence of the latter despite ongoing malnutrition in patients with anorexia nervosa.