Peak cardiac power output and cardiac reserve in sedentary men and women

Background and Purpose: Cardiac power output (CPO) and cardiac reserve (CR) are novel parameters of overall cardiac function. The purpose of this study was to determine differences in values of the CPO at rest and peak exercise and CR in sedentary men and women. Material and Methods: Thirty healthy men (age 21.2 +/- 0.7 years, body mass 63 +/- 6.3 kg, height 168.3 +/- 5.1 cm) and thirty healthy women (age 21.3 +/- 1.9 years, mass 82.5 +/- 79 kg, height 181.9 +/- 4.9 cm) were included in this study. Echocardiography was used to assess cardiac and hemodynamic parameters. CPO was calculated, at rest and after performed maximal bicycle test, as the product of cardiac output and mean arterial pressure, and CR as the difference of CPO value measured at peak exercise and at rest. Results: At rest, the two groups had similar values of cardiac power output (1.04 +/- 0.3W versus 1.14 +/- 0.25W, p > 0.05). CPO after peak exercise was higher in men (5.1 +/- 0.72W versus 3.9 +/- 0.58W p < 0.05), as was cardiac reserve (3.96 +/- 0.64W versus 2.86 +/- 0.44W p < 0.05), respectively. After allometric scaling method was used to decrease the effect of body size on peak CPO, men still had significantly higher peak CPO (2.79 +/- 0.4 W m(-2) versus 2.46 +/- 0.32W m(-2), p < 0.05). At peak exercise, a significant positive relationship was found between cardiac power output and end diastolic volume (r=0.60), end diastolic left ventricular internal dimension (r=0.58), stroke volume (r=0.86) and cardiac output (r=0.87). Conclusion: The study showed that men had higher CPO after peak exercise and greater cardiac reserve than women, even after decreasing body size effect.