短期間の運動が中高齢者の内臓脂肪面積および糖代謝能に及ぼす影響

抄録

Excess accumulation of visceral fat is reported to promote insulin resistance. However, it is not known whether or not insulin resistance improves without reducing visceral fat. Recent studies have reported, however, that exercise can improve insulin resistance. The aim of this study was to examine the effects of low-intensity exercise training on insulin resistance and visceral fat. Participants were 26 older adults, aged 63.9 ± 3.9 years, who were divided into two groups based on visceral fat area (VFA, cm²) measured by X-ray computed tomography. Eight men (153.4 ± 49.4 cm²) and 5 women (151.9 ± 45.5 cm²) were classified as having a VFA of 100 cm² or more (VFO group), and 6 men and 6 women as having less than 100 cm² (C group). After a 14-week exercise training program, VFA in women of the VFO group was significantly reduced (126.3 ± 40.0 cm²) ; though it did not reach 100 cm². However, homeostasis model assessment (HOMA-IR), an index of insulin resistance, significantly improved from 4.6 ± 1.9 to 2.2 ± 1.1 among women in the VFO group. These data suggest that improvements in insulin resistance for women with relatively high VFA are weakly associated with exercise-induced reductions in VFA. Based on these results, the activation of skeletal muscle with physical activity has the possibility of being independently associated with an improvement in insulin resistance without a significant decrease of VFA.