Centrifugal or centripetal force (never remember which). Just walk for a while with our hands waving above your head, jons a good'un.
Of course if you had the same swelling of your feet then you do have a problem see your doc. Don't veins have kind of built invalves to stop the blood rushing back, thinner walls too so your muscles move the contents from valve to valve. Whereas arteries coming straight from the heart have thicker, stronger walls that rely on the higher pressure pulse fromt he heart to get the blood around. I am probably quite wrong as I dropped biology at 16 and only just remember doing the vein and artery drawings out of th bioogy book for revision.
Needless to say I guess the muscles in your arm aren't working onmoving blood around as efficiently if you are not carrying anything or moving them rather just letting them swing by your side for long periods of time.
Probably wrong. Of course is the reason for swollen fingers related to white swollen fingers on long walks?
