Abstract
BACKGROUND: Hormone sensitive lipase (HSL) is an enzyme that regulates adipose tissue lipolysis and plays an important role in chronic exercise-induced changes in adipose tissue metabolism. The purpose of this study was to determine whether aerobic exercise intensity influences abdominal adipose tissue HSL gene expression in obese women under weight loss. METHODS: Thirty women (body mass index (BMI) = 33.0 ± 0.7 kg/m(2), age = 58 ± 1 years) completed one of three 20-week interventions: caloric restriction alone (CR only, n = 8), CR plus moderate-intensity exercise (CR + moderate-intensity, 45%-50% heart rate reserve (HRR), 3 day/week, n = 9), or CR plus vigorous-intensity exercise (CR + vigorous-intensity, 70%-75% HRR, 3 day/week, n = 13). Each group had a similar prescribed energy deficit comprised of underfeeding alone (2800 kcal/week for CR only) or underfeeding (2400 kcal/week) plus exercise (400 kcal/week). Body composition and maximal aerobic capacity (VO(2)max) were measured, and subcutaneous abdominal adipose tissue samples were collected before and after the interventions. Adipose tissue HSL gene expression was measured by real time reverse-transcriptase polymerase chain reaction. RESULTS: All three interventions reduced body weight, fat mass, percent fat, and waist to a similar degree (all p < 0.01). In addition, all interventions did not change absolute VO(2)max, but increased relative VO(2)max (p < 0.05 to p < 0.01). Compared to pre-intervention, neither CR only nor CR + moderate-intensity changed adipose tissue HSL gene expression, but CR + vigorous-intensity significantly increased adipose tissue HSL gene expression (p < 0.01). The changes of HSL gene expression levels in the CR + vigorous-intensity group were significantly different from those in the CR only (p < 0.05) and CR + moderate-intensity (p < 0.01) groups. In the whole cohort, changes in adipose tissue HSL gene expression correlated positively to changes in absolute (r = 0.55, p < 0.01) and relative (r = 0.32, p = 0.09) VO(2)max. CONCLUSION: These results support a potential effect of aerobic exercise training intensity on hormone sensitive lipase pathway in adipose tissue metabolism in obese women under weight loss.