During each heartbeat, approximately 71 cm3 of blood is pushed from the heart at an average pressure of 105 mm-Hg. Calculate the power output of the heart, in watts, assuming 68 beats per minute.

Answer 1

The work required per beat is
W = V*deltaP, where V is the volume pumped and delta p is the pressure increase provided. To get that in Joules, V must be in m^3 and deltaP must be in Pascals.

W = 71*10^-6 m^3*(105/760)*1.01*10^5 Pa
= 0.99 J
divide that by the time between beats, (60 sec/min)/(68 beat/min)= 0.88 s

The result is 0.99/0.88 = 1.13 Watts