Moderate-intensity and vigorous-intensity physical activity
According to the World Health Organization (WHO), the intensity of physical activity can be thought of as "How hard is a person working to do the activity?"
The intensity of different forms of physical activity varies from person to person, influence by many factors, including previous exercise experience and relative level of fitness.
The intensity of physical activities is measured by Metabolic Equivalents (METs).
Moderate intensity physical activity requires some effort and noticeably changes the heart rate, ranging from 3-6 METs.
Vigorous-intensity physical activity requires a large amount of effort, causes rapid breathing and a substantial increase in a person's heart rate. Anything over 6 METs is considered vigorous in its intensity.