Exercise, physical activity, and fitness are related concepts, but they are not interchangeable. Here are the differences:
Exercise: Exercise is a planned, structured, and repetitive form of physical activity with the goal of improving or maintaining physical fitness. It typically involves activities that are purposeful, such as weightlifting, running, cycling, or swimming, and is usually done for a specific duration and intensity.
Physical activity: Physical activity refers to any movement of the body that requires energy expenditure, including exercise. It can be planned or unplanned, and can include activities such as walking, gardening, or doing household chores.
Fitness: Fitness refers to the ability to perform physical activity and exercise without experiencing undue fatigue or injury. It includes a combination of muscular strength, cardiovascular endurance, flexibility, and body composition.
In summary, exercise is a type of physical activity that is planned, structured, and repetitive, and is done to improve or maintain physical fitness. Physical activity includes any movement of the body that requires energy expenditure, while fitness refers to the overall ability to perform physical activity and exercise