Physical activity is a bodily movement produced by skeletal muscles.
Physical activity requires energy expenditures and produce progressive health benefits.
Physical activity requires only a low to moderate intensity of effort.
Exercise is a type of physical activity that requires planned, structured, and repetitive bodily movement to improve / maintain one or more components of physical fitness.
Exercise program is a planned activity detailing a range of physical exercise & the amount of time each exercise should be performed where it is typically tailored to individuals' needs.