Some activity is better than none, and more, up to a point is better than less. So if you are physically active, meaning that you perform bodily skeletal muscle movement that results in a substantial increase in your energy expenditure, you gain greater health over being totally inactive. The greatest gains are seen with regular exercise of at least 30 minutes per day.
Exercise is a type of physical activity that is planned, and structured so that repetitive bodily movements are made to improve one or more components of fitness.
Health related fitness is characterized by five components, cadiovascular endurance, muscular strength and endurance, body fat and flexibility.
Skill related physical fitness would imply agility, coordination, power, balance and reaction time.
Additionally, it is important to clearly understand the wide range of intensities associated with physical fitness. More on this in a later post.