"To derive benefit from walking, Dr. Doty explained, it must be indulged daily and systematically. The best time for doing so is between the end of the working day and dinner. People who spend most of their time indoors, are advised to move their legs regularly. Golf, tennis, or a weekend hike, he said, are no equivalent for a daily walk since there is more to walking than physical exercise. Walking stimulates the mind, especially walking in congenial company."
quoted from Streets for People, by Bernard Rudofsky