Originally Posted by velocity
OH yah one more thing that really is wild to think about. Why do we get higher HR numbers when we are running vs. Biking and then again in biking vs. swimming?
It has to do with posture: the sensor that is regulating your HR to your effort and the amount of blood needed to pump to supply you with enough oxygen, is located in your neck. So if you are standing up, your sensor is straight above your heart and more effort is needed to push the blood up there. If you're bent over in a cycling position, the sensor is slightly lower relative to your heart; and if you're stretched out swimming it's almost even with your heart.