Questions & Answers about La marche est bonne pour la santé.
Why does the French sentence use La marche instead of a verb like marcher for "walking"?
Could I say Marcher est bon pour la santé instead?
Yes, you absolutely can! Using the infinitive Marcher as the subject works perfectly well to mean "walking". Notice that if you use the verb Marcher, the adjective takes the default masculine form bon instead of the feminine bonne.
Why is it la santé (the health) instead of votre santé (your health)?
In English, we often use possessive words like "your" to talk about people in general. French prefers to use the definite article (la, le, les) for general truths, abstract concepts, and body parts. So la santé just refers to health in a universal sense.