Relation between self-reported physical activity level, fitness, and cardiometabolic risk

Physical activity and cardiorespiratory fitness are associated with improved cardiovascular health and reduced all-cause mortality. The relation between self-reported physical activity, objective physical fitness, and the association of each with cardiometabolic risk has not been fully described. We studied 2,800 healthy Brazilian subjects referred for an employer-sponsored health screening. Physical activity level was determined as "low," "moderate," or "high" with the International Physical Activity Questionnaire: Short Form (IPAQ-SF). Fitness was measured as METs achieved on a maximal, symptom-limited, treadmill stress test. Using multivariate linear regression analysis, we calculated age, gender, and smoking-adjusted correlation coefficients among IPAQ-SF, fitness, and cardiometabolic risk factors. Mean age of study participants was 43 ± 9 years; 81% were men, and 43% were highly active. Mean METs achieved was 12 ± 2. IPAQ-SF category and fitness were moderately correlated (r = 0.377). Compared with IPAQ-SF category, fitness was better correlated with cardiometabolic risk factors including anthropomorphic measurements, blood pressure, fasting blood glucose, dyslipidemia, high-sensitivity C-reactive protein, and hepatic steatosis (all p <0.01). Among these, anthropomorphic measurements, blood pressure, high-sensitivity C-reactive protein, and hepatic steatosis had the largest discrepancies in correlation, whereas lipid factors had the least discrepant correlation. When IPAQ-SF and fitness were discordant, poor fitness drove associations with elevated cardiometabolic risk. In conclusion, self-reported physical activity level and directly measured fitness are moderately correlated, and the latter is more strongly associated with a protective cardiovascular risk profile.