A recent paper shows that exercise can make the skin look younger. This mechanism can be explained in many ways.
Exercise can make people sweat, help blood circulation and expel water, and the skin condition like orange peel may be improved.
In addition, a preliminary survey I made some time ago showed that a considerable number of patients with seborrheic dermatitis (prominent features are shiny face, large pores and red skin) rarely sweat; Moreover, some people exercise and sweat for a while. This is probably because the activity of sweat glands can not only bring moisture to the epidermis, but also secrete antibacterial peptides, which helps to inhibit harmful microorganisms and thus maintain skin and health.