PURPOSE: Obesity is associated with increased platelet reactivity. Greater platelet reactivity presages adverse events in patients with coronary artery disease (CAD). We investigated whether exercise training and weight loss reduce platelet reactivity in overweight subjects with CAD.
METHODS: Study subjects (N = 46) were enrolled in a prospective randomized study of exercise training and behavioral weight loss, which contrasted the amount of exercise performed (750 vs >3000 kcal/week). Platelet reactivity was assessed with the use of flow cytometry as the percentage of platelets expressing P-selectin or capable of binding fibrinogen in response to 1 μM adenosine diphosphate in blood before and after a 4-month program of exercise and behavioral weight loss. Markers of inflammation (high-sensitivity C-reactive protein), procoagulant activity (tissue plasminogen activator, plasminogen activator inhibitor 1), insulin sensitivity, body composition, physical activity, and fitness were also recorded.
RESULTS: Platelet reactivity as assessed by P-selectin expression was decreased after exercise training and weight loss in study participants (from 34 ± 17% to 29 ± 17%; P = .01). The decrease was more pronounced in women (by 13% vs 2% in men; P < .01). The change in platelet reactivity was not independently associated with measures of body composition or fitness. After controlling for exercise group and gender, the change in platelet reactivity was associated with changes in high-sensitivity C-reactive protein (r = 0.46) and insulin sensitivity (r = 0.46).
CONCLUSIONS: In overweight patients with CAD, exercise training and weight loss are associated with a decrease in platelet reactivity that may predict an improved prognosis.