Studies carried out by research scientists from the University Of Split School Of Medicine in Croatia and the Norwegian University of Science and Technology show that doses of vitamins C and E can reduce ill-effects of scuba diving on diversâ circulation. The scientists gave doses of vitamins C and E, which work as antioxidants, to seven professional divers before a 30-minute, 30-metre dive. The divers performed two dives 24 hours apart, with doses of the vitamins administrated two hours before the second dive. Six of the divers took part in a second trial eight months later, in which some were given the antioxidants while other received dummy pills. Research found that antioxidant treatment prevented endothelial dysfunction which stops the cells lining the blood vessels working properly, which can cause high blood pressure.