The Effects of Stress on the Heart Rate

The heart has to pump more during that time when there's breath in the lungs and then when the air is out of the lungs there's less work to do. If we're not in a stress state it has a chance to lower the heart rate because your diaphragm goes up which puts more pressure on the entire thoracic cavity. All that pressure translates backwards towards the spine and right along the spine is the dorsal vagal nerve this is the parasympathetic nerve. It sends a signal down to the heart that hey there's more pressure therefore lower the heart rates so the heart rate comes down a little bit.