Women have higher levels of growth hormone at rest and during the first 30 minutes of moderate-intensity treadmill exercise compared to men, regardless of their training background.

In resting conditions, higher estradiol levels correlate with higher growth hormone levels, but during physical exercise, higher estradiol levels correlate with lower growth hormone levels, showing that the relationship between these two hormones changes depending on whether the body is at rest or active.

During prolonged exercise, the intensity of the workout and whether a person is a trained runner or not account for about one-third of the differences in how much growth hormone their body releases.

Men who regularly train for endurance sports show higher and longer-lasting increases in growth hormone during and after long workouts compared to men who do not train for endurance sports.