Purpose: To investigate the effect of a yearlong moderate-intensity aerobic exercise intervention on C-reactive protein (CRP), serum amyloid A (SAA), and interleukin 6 (IL-6) among overweight or obese postmenopausal women.
Methods: In a randomized controlled trial, 115 postmenopausal, overweight or obese, sedentary women, aged 50-75 yr were randomized to an aerobic exercise intervention of moderate-intensity (60%-75% observed maximal HR), for ≥45 min·d−1, 5 d·wk−1 (n = 53), or to a 1-d·wk−1 stretching control (n = 62), on an intent-to-treat basis. CRP, SAA, and IL-6 were measured at baseline, at 3 months, and at 12 months.
Results: From baseline to 12 months, CRP decreased 10% in exercisers and increased 12% in controls (P = 0.01); no effects were observed for SAA and IL-6. Among participants at baseline who were obese (body mass index (BMI) ≥ 30 kg·m−2) or had abdominal obesity (waist circumference (WC) ≥ 88 cm), exercise resulted in a more pronounced reduction in CRP (BMI ≥ 30 kg·m−2, P = 0.002; WC ≥ 88 cm, P < 0.0001), borderline for SAA (BMI ≥ 30 kg·m−2, P = 0.08; WC ≥ 88 cm, P = 0.04); no intervention effects were observed among women who did not have these characteristics. Overall, weight loss was minimal in the exercise intervention (∼1.8 kg). Linear trends were observed between CRP and 12-month changes in aerobic fitness (Ptrend = 0.006), exercise adherence (Ptrend = 0.004), percentage body fat (Ptrend = 0.002), body weight (Ptrend = 0.002), WC (Ptrend = 0.02), and intra-abdominal fat (Ptrend = 0.03).
Conclusions: A moderate-intensity exercise intervention reduced CRP for 12 months among women who were obese at baseline. These findings support the role of exercise in modulating inflammatory processes that are related to increased risk of chronic disease among obese women.