BACKGROUND:

It is suggested that fat deposition within midthigh muscle, represented by low-density lean tissue, increases with deconditioning and obesity and is associated with risk factors for cardiovascular disease (CVD) in women.

OBJECTIVE:

We determined the effects of a 6-mo weight loss and walking (3 times/wk) program (WL+AEX) on midthigh low-density lean tissue and glucose and lipid metabolism in 24 sedentary, obese [body mass index (kg/m(2)): 32 +/- 1 (mean +/- SEM)] postmenopausal women aged 58 +/- 1 y.

DESIGN:

Total body fat and fat-free mass were measured by using dual-energy X-ray absorptiometry. Intraabdominal fat (IAF), subcutaneous abdominal fat (SAF), midthigh fat, midthigh muscle, and midthigh low-density lean tissue areas were measured by using computed tomography. Glucose and insulin responses were determined with a 3-h oral-glucose-tolerance test.

RESULTS:

Body weight decreased 8% (P: < 0.001) and maximal aerobic capacity increased 8% (P: < 0.001) with the weight loss and walking program. Total body fat decreased by 15% (P: < 0.001) whereas fat-free mass did not change. IAF and SAF decreased by 18% and 16%, respectively (P: < 0. 001). Midthigh fat and midthigh low-density lean tissue decreased by 16% and 18%, respectively (P: < 0.001), and midthigh muscle area increased by 7% (P: < 0.05). Fasting plasma insulin decreased by 12% and total glucose and insulin areas under the curve decreased by 6% and 24%, respectively (P: < 0.05). HDL-cholesterol concentrations increased 8% (P: < 0.05) and triacylglycerol concentrations decreased 19% (P: < 0.001).

CONCLUSION:

Increased physical fitness and weight loss reduce midthigh low-density lean tissue and improve glucose and lipid metabolic risk factors for CVD in obese postmenopausal women.