Chiropractic adjustments of the upper neck- shown to lower blood pressure by 27 overall points (more powerful on average than 2 doses of blood pressure lowering medications) without having prior experience of neck or back pain.

-Journal of Human Hypertension May 2007;21(5):347-52. Epub 2007 Mar 2.

Blood Pressure Lowering Effects

Research proves that chiropractic adjustments directly affect the autonomic nervous system, improving heart rate variability and increasing the heart's ability to recognize and adapt to stressors. 

-Journal of Manipulative and Physiological Therapeutics - May 2006. 

Improved Heart Rate Variability