Your body works just like a machine, so treat it like one.  When you go out to do your run, monitor your body.  It works like an outboard motor on a boat.  When you first crank it, the motor is cold; it spits, sputters, smokes and sometimes even stalls.  Just like your body, the engine needs to warm slowly.

As you run that rough-running engine out of the harbor, it starts to smooth out a little bit as it warms up and and as you give it a little more throttle, then you open it up and you start to leave a nice clean wake, the engine finally runs efficiently, warmed up  just like your body should.

For maximum efficiency during your work outs, start very slowly and warm your body’s engine carefully and then go full throttle!