Degree Name

Master of Science (Hons.)


Department of Biological Sciences


Cardiovascular responses of trained male Cyclists (65 ±2.1 years; n=10), trained Runners (65 ±3.4 years; n=ll), and untrained healthy Controls (66 ±1.1 years; n=10) were examined at supine and seated rest and during incremental upright cycle ergometry (20 W.min"^). Mean aerobic power of Cyclists (53.75 ±1.58"^ min O was significantly higher (p<0.05) than that of Runners (47.95 ±3.94^ min'^), whereas values for both groups were significantly higher than that of Controls (28.42 ±1.26 mLkg-^min'^). Resting heart rate of Cyclists (56 ±1.26 b.min*^) and Runners (51 ±2.57 b.min"^) were significantly lower than that of Controls (68 ±3.43 b.min'^). Using impedance cardiography, stroke volume and stroke index, cardiac output and cardiac index, and total peripheral resistance response to exercise was compared. Also, blood pressure and rate pressure product were measured throughout exercise. Cyclists' and Runners' stroke volume significantly increased by 41% and 47% at a heart rate of 90 b.min"^ and continued to rise throughout exercise, whereas stroke volume of the Control subjects increased by 31%. Cardiac index and stroke index of Runners and Cyclists was significantly higher than that of Controls during exercise. In addition, Runners' total peripheral resistance and rate pressure product response were significantly lower then Cyclists and Controls throughout exercise.