Effect of aerobic exercise on insulin resistance and central adiposity disappeared after the discontinuation of intervention in overweight women

PURPOSE: This study aimed to assess whether the benefits of exercise on central adiposity and insulin resistance (HOMA-IR) are maintained after discontinuation of intervention in the overweight/obese (OWOB) women. METHODS: The study subjects were from 2 independent studies with similar aerobic exercise (AE) intervention programs. In study I, 15 OWOB postmenopausal women with pre-diabetes (body mass index, BMI = 24–33 kg/m(2), aged 52–65 years) completed an 8-month exercise intervention and were followed for 2 years after the intervention. In study II, 12 OWOB (BMI = 25–35 kg/m(2), aged 30–50 years) premenopausal women participated in a 6-week AE and were followed for 4 years after the intervention. The exercise program consisted of progressive AE with intensity of 60%–75% of initial fitness level, 30–60 min/time and 3–5 times/week. Fat mass (FM) was assessed by Dual Energy X-ray Absorptiometry (DXA Prodigy; study I) or bioelectrical impedance device (Inbody 720; study II). Plasma glucose and insulin were assessed by chemiluminescent immunoassay and HOMA-IR was calculated. RESULTS: Both 8-month and 6-week moderate AE were effective in reducing HOMA-IR (−18.9%, p = 0.012 and −26.7%, p = 0.046, respectively), and 8-month AE reduced FM at upper abdominal region (−6.2%, p = 0.021). However, these improvements were not maintained in either study at the follow-up. CONCLUSION: The AE program used in these studies was effective to reduce insulin resistance and/or FM in central body region among overweight and obese women. However, when exercise intervention was discontinued, the beneficial effects following both short- and long-term intervention disappeared. Thus maintaining exercise seems to be required if one wants to reap the benefits of exercise in the long-term.