摘要：Research background and hypothesis. Potential mechanisms through which muscle perfusion is altered during prolonged exercise are not fully understood. The methods applied in the analysis of human data are very important because many crucial variables are not directly measureble or even identifiable. Research aim was to find out the peculiarities in concatenation between central and peripheral cardiovascular changes under conditions of increasing fatigue. Research methods. Well-trained endurance runners underwent a 50 W increase in workload (bicycle ergometry) every 6 minutes and they exercised until inability to continue the task. Dynamics of concatenation between cardiac output and systolic arterial blood pressure (ABP), diastolic ABP and total peripheral resistance were assessed using a method based on matrix theory proposed by Lithuanian scientists. Research results. The increase of cardiac output during exercising has the same tendency of stepwise increase of workload, but changes of systolic and diastolic ABP with accumulation of fatigue could be characterized as linear type dependent with the time of exercising. The concatenation between the changes in cardiac performance and behaviour of peripheral vasculature increased at onset of exercising and the decrease or loss of the concatenation led up to inability to continue exercising. Discussion and conclusions. The importance of peripheral factors, i. e. decrease of diastolic blood pressure, reduction of total peripheral vascular resistance plays an increasingly significant role for cardiac output during continuous exercising. The concatenations between the changes of these indices and cardiac output increase and in the case of high-grade fatigue concatenations begin to decline. Keywords: cardiac output, periferal vascular resistance, concatenation.
