Heart rate variability (HRV) is the variation in time between consecutive heart beats. It is universally accepted as a non-invasive marker of autonomic nervous system (ANS) activity and health. HRV is regulated by the ANS and its sympathetic (accelerator) and parasympathetic (brake) branches. The sympathetic branch is the stress or fight and flight system, increasing heart rate and readying us to act and react with the ability to meet everyday demands of life. The parasympathetic side is the rest and digest system, which slows the heart rate, allowing the body to calm down and recover. If a person is experiencing chronic stress, either physical or emotional, it’s like driving a car with the foot on the brake and the accelerator at the same time, causing overload. If excessive or prolonged it can lead to burnout and disease.

HRV changes from day to day based on activity levels and amount of external stress. Internal stress factors include poor nutrition, alcohol use, illness etc. High HRV is indicative of good health.