If you have varicose veins, you may benefit from wearing support hose when you stand around, but not when you exercise.
Veins in your legs carry blood up toward your heart. When you stand up, gravity pulls blood down to your feet. Your leg veins are supposed to have valves in them that keep the blood from backing up, but some people have veins that are too wide apart and cannot close properly and others are born without any valves. These people have varicose veins that widen with blood and look like snakes. Support hose squeeze the legs and help to prevent blood from pooling in veins and distending them.
When you exercise, the force of your contracting muscles keep blood from pooling so you don’t need support hose. When your leg muscles relax, the veins near them fill up with blood. When your leg muscles contract, they squeeze the veins near them and pump blood up toward your heart. The pumping action of your leg muscles exerts such a strong force to empty your veins, that you don’t need support hose. In hot weather, the support hose can act as a barrier to prevent heat loss. Your body temperature may rise and you may tire earlier. If you have varicose veins, support hose help to keep the veins from swelling when you stand, but it is unlikely that they are needed during exercise.