Final answer:
The frequency of isotonic exercise depends on individual fitness goals and current level of physical activity. Adults should engage in at least 150 minutes to 300 minutes per week of moderate-intensity aerobic activity or 75 minutes to 150 minutes per week of vigorous-intensity aerobic activity. Additionally, muscle-strengthening activities should be done on 2 or more days per week.
Step-by-step explanation:
Isotonic exercise is a type of exercise that involves movement of the joints and muscles. It focuses on the whole body and includes activities like running, swimming, and weightlifting. The frequency at which isotonic exercise should be done depends on the individual's fitness goals and current level of physical activity. As per the guidelines provided by the Department of Health and Human Services, adults should engage in at least 150 minutes to 300 minutes per week of moderate-intensity aerobic activity or 75 minutes to 150 minutes per week of vigorous-intensity aerobic activity. Preferably, aerobic activity should be spread throughout the week. In addition, adults should also do muscle-strengthening activities on 2 or more days per week.