3.3 Time
The recommended duration of an aerobic exercise session is dependent on several factors, such as the participant’s goals and fitness levels, and the intensity of exercise. Obviously, the higher the intensity of the exercise, the shorter will be its duration. The ACSM 2011 position stand recommends 30-60 minutes of purposeful moderate exercise per session, 20–60 minutes of vigorous exercise per session, or 20–60 minutes of a combination of moderate and vigorous exercise per session for healthy adults (Garber et al., 2011). Again, the requirements for sportspeople will be dependent on the demands of their sport (specificity principle). Current UK physical activity guidelines suggest that adults should engage in daily moderate intensity physical activity adding up to at least 150 minutes per week (often recommended as at least 5 x 30 minute bouts per week) (Department of Health, 2011).