Comparison of Hemodynamic and Left Ventricular Responses to Increased After-Load in Healthy Males and Females

Abstract

Hemodynamic and left ventricular responses were studied echocardiographically in 20 males (31.5 ± 4.5 yrs) and 20 females (30.4 ± 4.3 yrs) at rest and during 3 min of isometric deadlift exercise at 30% of maximum voluntary contraction. Maximal tension exerted was significantly (P < .001) lower in the female group (87.4 ± 8.1 kg) compared with the male group (127.3 ± 15 kg). Significant (P <.001) increases in heart rate and contractility index were noted in both groups during exercise compared to the resting values. Mean arterial blood pressures were significantly (P < .05) higher in the males at rest and during exercise. Ejection fraction and fractional shortening, both at rest and during exercise, differed significantly (P < .05) between the two groups. It was raised by exercise only in the males (from 62 ± 5% to 65 ± 5% and 32 ± 4% to 35 ± 4%, respectively) but remained unchanged in the females. No significant changes in end diastolic dimension and stroke volume were observed in either group during exercise. End systolic dimension was significantly (P < .001) lower during exercise in females and males (from 3.25±.23 to 3.1 ±.26 and 3.12±.33 to 3.00±.32 cm, respectively). These data indicate that hemodynamic and left ventricular function in normal male and female subjects were augmented during submaximal isometric exercise. However, females do so with lower after-load than males.

Key words

Isometric exercise - gender - echocardiography - left ventricular function