T is torque
I is mass moment of inertia
w is angular velocity.
Now, initial torque requirement for any machine to start or ignite is high. This implies that inertia required to meet this high torque should be sufficiently high, as inertia is directly proportional to torque (seen from the above equation).
Overcoming our very own state of rest or inertia (namely, lethargy or comfort), needs high power (will-power, I must say).
P is power
N is speed
T is torque.
Hence, beginnings are mostly arduous.
But, once this state of rest is overcome, the machine functions at low torque and hence low power as torque is directly proportional to power.
Similar applies in our case too because ultimately even we are machines.