Effects of acute exercise on insulin binding to monocytes in obesity

The effect of 3 hr of cycle erogmeter exercise on ¹²⁵I-insulin binding to monocytes was studied in 8 obese and 10 nonobese control subjects. In the basal state before exercise, total specific ¹²⁵I-insulin binding to monocytes in obese subjects (4.8% ± 0.3%) was 25% lower than in control subjects (6.6% ± 0 0.4%, p < 0.01). During exercise, insulin binding increased in both groups (p < 0.05), but the rise in obese subjects was minimal (13% ± 1%) and was 60%–70% lower than in controls (36% ± 3%, p < 0.01). The data indicate that the increment in insulin binding to monocytes induced by acute exercise is diminished in obesity.