The effect of daily walking on body fat distribution was investigated using an electronic pedometer and ultrasonography. Subjects were 77 women, aged 31 to 72 years. They were divided into four groups according to the average number of steps they walked per day (I<7,500, 7,500 ≤II<10,000, 10,000 <III<12,500, 12,500 ≤IV). Subcutaneous fat in the trunk and limbs, and the minimum thickness of subcutaneous fat (Smin) and the maximum thickness of preperitoneal fat (Pmax) below the xiphoid process were measured by ultrasonography. Abdominal wall fat index (AFI) reflecting the intra-abdominal fat accumulation was obtained by dividing Pmax by Smin. Fat distribution was analyzed by ANCOVA, controlled for age, body mass index (BMI), percent body fat, and menopausal status. Energy and macronutrient intake were obtained through a nutritional survey. There were no significant differences in anthropometric variables, energy and macronutrient intake, and subcutaneous fat thickness in trunk and limbs. Pmax of Group I was significantly higher than Group IV. Furthermore, Group I showed significantly higher AFI than the other three Groups (II, III, IV). The results of this study suggested that women who walked less than 7,500 steps per day tend to have significantly increased intra-abdominal fat accumulation.
Keywords: B-mode ultrasonography; abdominal wall fat index; fat distribution; intra-abdominal fat; walking.