RELATIONSHIP OF PHYSICAL WORKING CAPACITY , BLOOD-PRESSURE AND OTHER ARTERIAL-HYPERTENSION RISK-FACTORS TO THE RATE OF RED-BLOOD-CELL NA+ LI+ COUNTERTRANSPORT/

The relationship of physical working capacity (PWC), blood pressure an d other arterial hypertension risk factors. to the rate of red blood c ell Na+/Li+ counter-transport was examined in a representative sample comprising 60 individuals (22 males and 38 females) whose age was 35-5 4 years. Regression analyses demonstrated that there was no significan t relationship between PWC and the rate of red blood cell Na+/Li+ coun tertransport, but a significant correlation was found between the rate of Na+/Li+ countertransport and ''double product'' (DP) as an indirec t indicator of PWC and heart rate. Thus, there is a heart rate- and DP -mediated correlation between the rate of red blood cell Na+/Li+ count ertransport and the level of PWC. The magnitude of a decrease in the r ate of red blood cell Na+/Li+ countertransport depends inversely on th e dynamics of heart rate in males and females and directly on the dyna mics of DP in females. Hence, there is a direct relationship between t he magnitude of a reduction in the rate of red blood cell Na+/Li+ coun tertransport and that: of PWC increment during exercise.