Blood pressure is one of the many functions controlled by your autonomic nervous system. The vagus nerve is a part of the brain stem and the extension of your parasympathetic nervous system which plays a key role in blood pressure control. When the nervous system is stressed out, arteries contract and blood pressure increases. Chiropractic stimulates the parasympathetic nervous system and can help lower blood pressure by reducing stress. Chiropractic is a neurologically based, holistic intervention with widespread affects.