Summary Bioelements are related with the main functions of organism: growth, development, reproduction, metabolism, are a part of bones, are important to oxygen transportation, to muscle contraction and etc. Bioelements as structural and functional components of biosubstrats, perform regulational function of different organs. Topicality. There are many studies on different sports athletes about changes of bioelements while performing different physical activity. Physiological and biochemistry cathedral of Lithuanian academy of physical education has made a lot of studies on handball teams players, track and field athletes about changes of biolements while performing physical activity, but we still don‘t have information about fitness and aerobics exercise influence on changes of bioelements. It was interesting for us to study fitness and aerobics exercise influence on changes of bioelements (K, Na, Ca, Cl, Fe ). Novelty. We don‘t have information how fitness and aerobics exercise influence of bioelements (K, Na, Ca, Cl, Fe ).changes in literaure. Practical sense for sportsmens its very important to restore of water and saline balance . after the physical activity Hypothesis. Body looses a lot of water and mineral salts while sweating, so we thought that different mineral salts concentration will appear in the venous blood of women who perform aerobic and fitness exercises. The aim of the study is to determine the changes of bioelements (K, Na, Ca, Cl, Fe) in venous... [to full text]