The intensity of a workout refers to?

The intensity of a workout refers to the level of effort or exertion required during physical activity. It can be measured by factors such as heart rate, the amount of weight lifted, or the speed of movement. Higher intensity workouts typically involve more vigorous activities that push the body closer to its limits, leading to greater calorie burn and improved fitness gains. Conversely, lower intensity workouts are generally easier and can be sustained for longer periods.