BACKGROUND AND AIMS: Physical inactivity is linked to low-grade inflammation, endothelial dysfunction and cardiovascular disease. We aimed to determine effects of active commuting and leisure time exercise on markers of low-grade inflammation and endothelial function in overweight and obese women and men.

METHODS: We randomized 130 younger (20-45 years), physically inactive, healthy, overweight and obese (BMI: 25-35 kg/m2) women and men recruited from the Copenhagen area, Denmark, to either 6 months of habitual lifestyle (CON, n = 18), active commuting (BIKE, n = 35), or leisure time exercise of moderate (MOD, ∼50% VO2peak, n = 39) or vigorous intensity (VIG, ∼70% VO2peak, n = 38). Fasting blood samples were collected at baseline, 3, and 6 months and analyzed for concentrations of C-reactive protein (CRP), fibrinogen, von Willebrand factor (vWF), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor type 1 (PAI-1), and 90 participants (CON, n = 16; BIKE, n = 19; MOD, n = 31, VIG, n = 24) were included in a per-protocol analysis.

RESULTS: We observed lower concentrations of CRP in MOD compared with CON at 6 months (p = 0.013) and within-group decreases in CRP in BIKE (3 months: p = 0.045) and MOD (3 months: p = 0.061; 6 months: p = 0.038) corresponding to a 30% decrease in BIKE and 19% in MOD from baseline till 6 months. No effects of exercise were observed on fibrinogen, vWF, t-PA, PAI-1 or the t-PA/PAI-1 ratio within or between groups.

CONCLUSIONS: Our findings suggest an anti-inflammatory effect of active commuting and moderate, but not vigorous, intensity leisure time exercise, but no alterations in endothelial function during 6 months of intervention.