The contours of the face play a major role for our looks and perception
through others. When we are young our cheeks are full and our cheek bones
and jaw lines are well defined giving convex and strong contours to our
faces.
With aging the lower face gets fuller, resulting in a rather square shape;
cheeks and temples loose their fatty tissue and may give a sunken in
appearance. While in addition the skin starts to sag, jowls are forming
along the jaws.
In long distance runners and after loosing large amounts of body weight
we can observe a similar atrophy of the tissues which can also give a
tired or worn out appearance.