What causes parasympathetic activity

Stimulating the vagus nerve stimulates the parasympathetic nervous system, which in turns reduces our neurophysiological experience of stress. It reduces our heart rate and blood pressure. It influences the limbic system in our brain, where emotions are processed.

Explanation:

so i really think that most of the health care industry be doing more bad than good.

exercising at a moderate intensity, and slowly increasing the duration.