High-sensitivity C-reactive protein levels and treadmill exercise test responses in men and women without overt heart disease

BACKGROUND: C-reactive protein (CRP) is a marker of systemic inflammatory activity and may be modulated by physical fitness. Treadmill exercise testing is used to evaluate cardiovascular health through different variables including exercise capacity, heart rate and blood pressure responses. It was hypothesized that CRP levels are associated with these variables in men and women without overt heart disease. METHODS: A total of 584 asymptomatic subjects (317 [54.3%] women and 267 [45.7%] men) were enrolled in the present study and underwent clinical evaluation. CRP levels in men and women were examined relative to clinical characteristics and to variables of treadmill exercise testing: peak heart rate, exercise systolic blood pressure, exercise time, chronotropic reserve and heart rate recovery at the first and second minutes after exercise. Multivariate analysis was performed using a log-linear regression model. RESULTS: In women, exercise time on the treadmill exercise test (P = 0.009) and high-density lipoprotein cholesterol levels (P = 0.002) were inversely associated with CRP levels. Body mass index (P < 0.001) and total cholesterol levels (P = 0.005) were positively associated with CRP levels. In men, exercise time on the treadmill exercise test was inversely associated with CRP levels (P = 0.015). Body mass index (P = 0.001) and leukocyte count (P = 0.002) were positively associated with CRP levels. CRP levels were not associated with peak heart rate, chronotropic reserve, heart rate recovery at the first and second minutes, or exercise systolic blood pressure. CONCLUSIONS: These findings contribute to the evidence that CRP is lower in individuals with better exercise capacity and demonstrate that this relationship is also apparent in individuals without overt heart disease undergoing cardiovascular evaluation through the treadmill exercise test. Lowering inflammatory markers may be an additional reason to stimulate sedentary individuals with low exercise capacity in the treadmill exercise test to improve physical conditioning through regular exercise.