Nowadays, many doctors recommend old people, who cannot do gym or such huge physical fitness exercises, to walk, as walking is considered and a clinically proven very good way to keep good health for the aged people.
Our doctor prescribes the same, but he is a bit different. According to him, walking only in the morning helps keeping good health. Walking in the evening has no good effect on the health of the person.
My question is, walking is a good physical exercise, but how does it matter if I walk in the morning or evening? Can anyone give a proper scientific explanation for what the doctor says? I cannot seem to find any, and neither can the doctor tell me anything satisfactory.