The intensity of exercise is a primary factor determining metabolic adaptations, specifically leading to enhanced insulin sensitivity and improved regulation of blood glucose.

Study: Effects of exercise intensity on postprandial improvement in glucose disposal and insulin sensitivity in prediabetic adults.

Working out helps your body handle sugar and insulin better, and working out harder might help a little bit more, but the study couldn't prove that harder is definitively better than moderate exercise—both helped significantly.

Study: Exercise intensities and metabolic health: Targeting blood glucose, insulin, and C-peptide levels in adults with prediabetes in the postprandial state

The study found that working out at a moderate-hard level (70% of your max heart rate) was best for improving blood sugar and insulin, but working out even harder wasn't as good—so intensity matters, but harder isn't always better.

Study: Moderate-intensity exercise and high-intensity interval training affect insulin sensitivity similarly in obese adults.

The study found that doing high-intensity interval training and moderate-intensity exercise both improve your body's use of insulin about the same amount, so working out harder doesn't seem to give extra benefits for blood sugar control.