1. First Department of Cardiology, School of Medicine in Katowice, Medical University of Silesia, 40-635 Katowice, Poland
2. Faculty of Science and Technology, University of Silesia in Katowice, 40-007 Katowice, Poland
3. Department of Swimming and Water Rescue, Institute of Sport Science, The Jerzy Kukuczka Academy of Physical Education, 40-065 Katowice, Poland