You can't limit the definition of physical activity to gym routine or also the heavy exercise, when simpler activity and movement like walking can be considered healthy activity physically.
Certainly time is valuable, and people tend to lose the active life because of their job. Considering important benefit to gain from healthy life, and by considering exercise as part of it, then use it as the key.
The physical activity can be obviously seen as each movement of the body, and it involves the muscle, and surely the stamina to lose.
Meanwhile for exercise, the movement is done more specific, and to train body also psychically. Moreover, it's not a mistake to treat it same.
The activity can include your routine or daily habits as simple as walking, to sport like swimming.
Of course you can run the movement to train physique anywhere, even when you go to office.
You can also classify the physical activity based on many factors, like the intensity.
First of course the activity you do that is part of life everyday.
Just like walking or cleaning the hours that can help burn calories.
Next is exercise which is more focus with the movement you have planned.
Running, using a treadmill are definitely the example of exercise.
Of course for more specific, the exercise you must have "rules" that you can follow.
Doing exercise routine is not just for body fit, but also as new lifestyle especially for those who live in cities.
Age, gender, and the support from the family, as well as the equipment can shape how you do exercise.
Intensity basically can define how you do exercise, whether it's just light or heavy exercise.
Light exercise won't push you, and won't make your heart beat faster.
As the consequence, such activity can only help burn calories on smaller number.
Doing stretching, walking, even riding a bicycle can be still considered light exercise.
The moderate activity can push you more, and improve the temperature of body.
You'll get tired a little because of the activity, and some example of it like using the stair, bicycling, or walk with fast.
If you want the more significant calories to burn then heavier routine for exercise is needed.
The sport like swimming and running, given the intensity and how it affects the body, can be considered "heavy".
Of course the body will become weak eventually when you don't do exercise or move body on best amount, since the body is not trained well and you don't improve the strength.
Certainly exercise benefits are made for longer time, and to gain those benefits, then doing physical activity is so crucial, just like how you need sleep in life.
