Today will be part 4 of our four-part series about HOW chiropractic works. I strongly encourage you to read parts 1, 2, and 3 to get a full picture of what actually a chiropractic adjustment does for your body (find them on our blog). To recap, a chiropractic adjustment changes negative feedback going from the body to the brain to positive feedback, it strengthens your autonomic nervous system and improves the adaptability and self-regulation of the sympathetic and parasympathetic response, and it prevents overloading the HPA axis which stimulates the physiological stress response in the brain. But wait, there is more!
It has been shown that a series of chiropractic treatments can improve a marker called heart rate variability (HRV). Your heart rate is measured by taking your pulse for 15 seconds and then multiplying that number by 4 to get how many times your heart beat in 60 seconds. The HRV is not your heart rate. Your heart doesn't beat right on schedule at every second and it shouldn't. It might be .8 of a second and then 1.2 second and then 1.4 second. This is the variability of your heart beat and should fluctuate and not be very rigid.
A high heart rate variability is a sign of good health and healthy nervous system. HRV is a way of assessing the function of your autonomic nervous system adapting and changing to it's environment the body's changing needs. As opposed to a rigid or static heart rate that doesn't respond or change, a high heart rate variability will fluctuate in response to the demand and adapt to its surroundings. Chiropractic adjustments have been shown to influence heart rate variability even after one adjustment.
This small study found that HRV increased in patients between the ages of 25 and 55 who received consistent chiropractic adjustments for up to one year. HRV was monitored throughout their course of treatment and every patient saw improvement in their HRV. This study evaluates how chiropractic care influences the nervous system and that these changes can be immediate and have long lasting neurophysiological changes.