WHAT IS HEART RATE VARIABILITY (HRV) AND WHY DOES IT MATTER FOR HEALTH?
Think about your heartbeat. If you are an average adult, it will go “thump thump” around 60 to 100 times per minute. This is known as your resting heart rate. Between every “thump thump” lies a small period of time—let’s say around 1000 milliseconds—referred to as the “inter-beat-interval.”
Scientists used to believe that a steady heart rate throughout the day—and thus a consistent inter-beat-interval—is a sign of positive health. This makes intuitive sense; most of us still believe this. Yet, this notion has been turned upside down in the past few decades through research on “heart rate variability” (HRV).
HRV refers to the variation of inter-beat-intervals; in other words, HRV is the variability of one’s heart rate over a period of time. It represents an organism’s ability to continuously adapt to changing internal (i.e., bodily) and external (i.e., environment) circumstances. The fact that there is variability means that we can repeatedly deal with stressors (i.e. increased heart rate) and recover from them (i.e., decreased heart rate). HRV is easily assessed through electrocardiogram (EKG) and other non-invasive methods. Today the market is saturated with wearable devices (e.g., Fitbit, WHOOP) that track heart rate and HRV—offering ongoing assessment of well-being and resiliency.
Hundreds of studies have taught us that higher HRV is a sign of health and resilience. Higher HRV is correlated with a wide range of physical, cognitive, and emotional states and traits. Anxiety, depression, chronic pain, hypertension, among many other mental and physical illnesses, are correlated with lower HRV. HRV not only provides a window into our current state of health, but also predicts susceptibility to future illness (e.g., heart disease) and the course of an illness (e.g., cancer prognosis).
HRV is a marker of one’s ability to self-regulate, or find homeostasis, due to its intricate involvement in the autonomic nervous system. Changes in heart rate are mediated by the vagus nerve (the tenth cranial nerve), which plays a vital role in regulating bodily and brain functions. Chronic stress impairs vagal functioning, lowers HRV, and leads to poorer overall health. Stress resilience, on the other hand, strengthens vagal function, bolsters HRV, and in general leads to better health.
· Higher HRV (more variability in heart rate throughout the day) is indicative of greater health.
· Lower HRV puts one at greater risk for negative health outcomes, and impairs one’s ability to recover from stress and illness.
What Negatively Impacts HRV?
These factors can negatively impact HRV:
1. Chronic stress (physical, psychological, emotional social, and spiritual).
-Remember that a little stress, when managed well, is healthy. This is especially true if we appraise the stress positively as a challenge to help us achieve our goals.
2. Poor sleep
3. Poor diet
4. Lack of exercise
5. Physical illness – such as chronic pain, rheumatoid arthritis, heart disease, diabetes, and many others
6. Mental illness – such as anxiety, depression, posttraumatic stress disorder, and many others
7. Chronic substance use, including alcohol, cigarettes, and illicit drugs
8. A history of traumatic stress or childhood trauma
9. Social isolation
How can I improve my HRV?
These factors can improve HRV:
1. Good sleep
2. Healthy diet
4. Strong social support
5. Avoid or minimize harmful substances such as alcohol, cigarettes, and illicit drugs
6. Evaluate your caffeine use. The effects of caffeine on HRV may differ across people; while caffeine may disrupt healthy HRV, in some cases it might provide indirect benefits (e.g., through supporting mood or exercise goals)
7. Engage in a daily mindfulness/stress-reduction practice
8. Practice belly breathing! Ten minutes per day of slow, diaphragmatic breathing is one of the most direct and effective ways to strengthen HRV.
How else can I improve and get feedback on my HRV?
HRV Biofeedback is an empirically supported method of teaching self-regulation of the nervous system and strengthening HRV.
See our blog post on HRV Biofeedback for more information, or contact Marrero Psychology!
Dr. Chris Marrero, Clinical Psychologist (PSY23017) & Biofeedback Specialist:
Dr. Matthew Goodman, Postdoctoral Psychological Assistant & Biofeedback Specialist:
Matthew S. Goodman, Ph.D., BCB is a Postdoctoral Psychological Assistant and Board Certified Biofeedback Therapist in private practice with Dr. Chris Marrero. He specializes in teaching self-regulation techniques using practices such as mindfulness/meditation and biofeedback, and working with patient with co-occuring mental and physical health symptoms.