Authors came to conclusions that during the pre-deployment period submarine personnel are stressed out. During this period submarine personnel .usually resupply, conduct maintenance and other monitoring-and-checkout measures, which leads to functional stress. Authors came to conclusion that it is necessary to use simple and easy, but at the same time informative methods for early diagnosis of worsen functional health status. One of these methods is evaluation of indicators of cardiovascular system. This method is a base for functional health status prophylaxis.