A single session of resistance exercise consisting of 8 sets of 10 repetitions at 75% of one-repetition maximum for leg exercises improves whole-body insulin sensitivity by 13% ± 5% in healthy young men, as measured by the rate of decline in blood glucose following intravenous insulin administration, with effects persisting for at least 24 hours without changes in basal glucose or insulin levels.

Heavy leg exercises cause muscle fibers to contract forcefully, which triggers signals inside the muscle cells that move glucose transporters to the cell surface. These transporters pull glucose out of the blood even without insulin. This effect lasts for a full day because the transporters stay active on the cell surface and the muscle becomes more responsive to insulin, lowering blood sugar more efficiently.