Any bodily movement in which bones-muscles are strained and in which energy/ Calorie is spent, is called ‘physical activity’.
While repeated movement of any part of the body according to pre-decided plan is termed as exercise.
If you walk on a treadmill or do cycling daily for 20 minutes, it can be called exercise. while what you do as a part of your daily routine like, working in the kitchen, moving from one place to another on feet, going to office after parking the vehicle, climbing the stairs, doing household cleaning working in the garden, placing things up or down. playing field games, etc. can be called physical activities.
Both these-exercise and physical activities are beneficial to the heart and overall health.If possible, you should give a place to both in your daily life. It was learnt through a study on London transport employees done in 1953, that a conductor ( who keeps on moving in the bus to check tickets for the whole day ) has one-third the risk of getting heart attack as compared to the driver ( who keeps sitting for the whole day). We should give a place to physical activities in the daily life by doing work ourselves to the maximum possible extent.