The nature and extent of the stresses imposed upon the heart and circulation by Olympic competition varies markedly with the type of event. It is thus helpful to make an arbitrary classification of some of the main Olympic contests on the basis of the dominant physiological requirements (Table 1).
The atmosphere of competition imposes an intense psychological stress upon all contestants, and this necessarily acts upon the cardiovascular system. However, psychological stress is greater during anticipation of exercise than during actual performance. Other factors being equal, the cardiovasular effects of psychological stress are thus likely to be greatest in brief repetitive events (categories 4 and 1 of Table 1). All forms of exercise tend to increase the systolic blood pressure. However, certain types of circulatory strain seem related to the mean rather than to the systolic pressure. Elevation of the mean systemic pressure is a particular feature of sustained isometric
Roy J. Shephard. The Heart and Circulation Under Stress of Olympic Conditions. JAMA. 1968;205(11):775–779. doi:10.1001/jama.1968.03140370077017