How is "intensity" defined in the context of physical activity?

In the context of physical activity, "intensity" refers specifically to the degree of effort required to complete a physical activity. This measurement can vary greatly depending on the type of activity and the individual's fitness level. For example, running at a fast pace would be considered a high-intensity exercise compared to walking at a leisurely pace. Intensity can be assessed in several ways, including heart rate response, perceived exertion, or the ability to carry on a conversation during the activity.

Duration refers to how long the activity is performed, which is a separate metric and does not indicate how hard the activity is being performed. When discussing the variety of exercises included in a workout, we are referring to the range of different movements and modalities used, which is distinct from intensity. Similarly, the number of repetitions performed pertains to the volume of exercise and does not provide an indication of how hard the activity feels or the effort required. Therefore, the definition of intensity centered on the effort level is the most accurate understanding in this context.