The two forms are very healthy but what is the best form to do excercise? The benefits of gym exercise are: the intensity is better, there are no climatologically distractions, and you can focus more as there aren’t distractions. And the finals results are better.
But the disadvantages are: it is very boring running on a treadmill; you can have distractions.
The benefits of outdoors exercise are: reduces stress and anxiety, when you run near parks, gardens… you relax and the mind clears. Besides you become addicted because that feeling of liberation engages. And the only disadvantage is when the weather is bad.
Àngel V. A.
3rd ESO B