Heart Rate Variability

By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.

Heart rate variability (HRV) – the measure of the variation in time between your heart beats – is perhaps the most important biomarker you and your doctor should know. Why? Other, more familiar biomarkers of cardiovascular health – such as cholesterol numbers, blood pressure readings, pulse rate, C-reactive protein  – and you probably know your numbers by heart – all give us physicians useful information, but none can conclusively tell us whether you have a normal, healthy ticker.

Take cholesterol, for example. It’s a pretty poor indicator of heart disease, if you consider that more than half the people hospitalized with heart attacks have perfectly normal cholesterol numbers.

Related to the work of the autonomic nervous system (ANS), heart rate variability can be used to track the health and recovery of heart patients, and is a predictive indicator of overall cardiovascular health, risk of heart attack, and other cardiac issues. Essentially, it’s a physiological measure of emotional stress, and reflects what’s going on in the mind.

Unfortunately, unless your best friends are all cardiologists, you’ve probably never heard of HRV…I’m going to change that.

High and Low Heart Rate Variability

Heart-rate variability is a very simple measurement: It can be either high or low. If your heart beats with intervals of identical length between each pulse, you have “low” heart rate variability – which is not optimum. A low HRV has been linked to the development of cardiovascular disease and metabolic syndrome (diabetes, hypertension, and high cholesterol), and is prevalent in people who have had heart attacks. Decreased heart rate variability is also regarded as the most accurate reflector of stress, and even a predictor of sudden cardiac death.

On the other hand, if your heart beats with intervals of varying length, you have “high” heart rate variability – this is what you want – a normal heart rate range. The more easily your heart rate varies, the better off you are. An increased HRV shows that your heart is pumping as needed and responding to the demands of your body. It indicates a healthy, fit, and well­-rested heart.

Heart Rate Variability and Your Nervous System

To understand how HRV swings either high or low, you need a basic understanding of the autonomic nervous system (ANS). The ANS regulates heart beat, heart rate, blood pressure, body temperature, digestion, breathing, and other basic life-sustaining functions of the body over which we have no conscious control. The ANS is involved in all diseases.

This system is divided into two complementary but oppositional branches, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS). Both are regulated by chemical messengers called neurotransmitters, rather than by neural impulses from the central nervous system (the brain, the spinal cord, and the optic nerves).

The SNS prepares us for flight or flight by increasing heart rate, boosting the blood supply to the heart and muscles, and decreasing blood to the skin and other organs. By contrast, the PSNS works to conserve energy by lowering pulse rate and blood pressure and controls calming responses such as relaxation, digestion, and sleep. It is very active at night during sleep, when your body must regenerate its cells and tissues for the next day.

Both the SNS and the PSNS are important, and, in a healthy person, the two systems work harmoniously to keep the body in balance. But there’s a tendency for both systems to end up fighting each other. When someone cuts you off in traffic, your sympathetic nerves get going to speed up your heart. At the same time, your parasympathetic nerves are desperately trying to decelerate your heart and calm you. So your body is locked into an internal opposition. Think of this like driving with one foot on the gas pedal and one foot on the brake. That’s not good for a vehicle, and it’s not good for your heart either.

These imbalances affect your heart rate variability. If your PSNS has been weakened and your SNS is dominant, this will show up as low HRV. With low HRV, you’re often less able to go with the flow when faced with stressful situations and thus more prone to stress-related disorders such as cardiovascular problems, all because the heart is very vulnerable to stress and the emotions it produces. Improving parasympathetic tone is a key ingredient in reducing illness.

Test Your Heart Rate Variability

Where does your HRV stand? You can find out at your doctor’s office through a standard ECG, or the wearing of a Holter Monitor. Or, you can take a HRV test with a special machine called a heart rate variability biofeedback device. The test lasts about 10 minutes and is painless. Your health care provider will place a strap around your chest that monitors heart beats. Half of these are measured while you lie on your back, and the rest, while you are standing. The machine measures the intervals between each heartbeat, and you’ll come out of the test with a score of high or low.

How to Improve Your Heart Rate Variability

The good news is that you can raise your heart rate variability, protect your ANS, and thus reduce your odds of stress-related disorders, including heart disease. Here’s how:

1. Heart rate variability training: Regularly engage in stress management techniques

Essentially, you train your heart through regular practice to have a conversation with your mind, and ultimately alleviate stress. Over time, you can learn to generate a relaxation response that calms and balances the ANS. Focus mostly on physical activities that involve conscious breathing, such as Tai chi, yoga, Pilates, relaxation, meditation, and imagery sessions – and do these several times a week. I’m a huge fan of yogic pranayama breathing, and believe it’s one of the best ways to improve HRV.

Science backs me up on the importance of these activities. In a study conducted in India and published in 2015, researchers assessed the effect of yoga or swimming on HRV in 100 normal healthy young volunteers. They were divided into two groups: those who did yoga and those who swam. Heart rate variability was checked before the study, and afterwards. At the end of the 12-week experimental period, the volunteers who practiced yoga saw improvements in their HRV, compared to the swimmers, who did not. The researchers did not speculate as to why, but I feel that it had to do with the breathing, and its relaxing effect on the autonomic nervous system, that is so important in yoga. When you are in a yoga twist or stretch – especially if it’s uncomfortable – breathing through it will ease discomfort, while also improving HRV. I personally feel that alternate nostril breathing is the easiest way to improve your own heart rate variability.

2. Practice Earthing

Earthing, also known as grounding, supports heart rate variability and is actually a more passive method of heart rate variability training. You see, the Earth has a natural energetic field. When you have physical contact with the Earth’s surface, you absorb the natural healing energy of our planet. A study that I conducted with electrophysiologist Gaetan Chevalier demonstrated how Earthing improves HRV. We noted that Earthing counteracts stress by promoting a calming mode in the autonomic nervous system that regulates functions such as heart and respiration rates and digestion. Earthing can rapidly shift the ANS away from a typically overactive sympathetic mode associated with stress – and with this shift comes a higher HRV. As we concluded in the study, “contact with the Earth – whether being outside barefoot or indoors connected to grounded conductive systems – may be a simple, natural, and yet profoundly effective environmental strategy against chronic stress, ANS dysfunction, inflammation, pain, poor sleep, disturbed HRV, hypercoagulable blood, and many common health disorders, including cardiovascular disease.”

Earthing is easy to work into your lifestyle. You can do it by being barefoot outside, gardening, or swimming in the ocean. Other ways to ground include camping, hiking, or walking on the beach. You can also sleep, work, or relax indoors on special conductive sheets or mats connected to the Earth with wires plugged into a grounded wall outlet or a ground rod outside. Or you can just wear thin, plain leather shoes that let you make contact with the Earth’s natural vibration. By contrast, rubber soles like tennis sneakers or neoprene found in running shoes will keep you disconnected from the Earth. My recommendation is to ground at least 150 minutes a week.

3. Reduce Exposure to Electromagnetic Fields (EMFs)

Over-exposure to the electro-pollution of radio frequency from cell towers, cordless telephones, cell phones and even Wi-Fi has the potential to reduce HRV. Accordingly, reduce the time you spend exposed to wireless EMFs from your “smart” devices. Some simple ideas include: limiting the number and duration of cell phone calls, using your speaker phone instead, turning off your router at night, unplugging electrical equipment when not in use, standing 30 feet back from your microwave when cooking; and not living near cellular towers and high-tension power lines. Use a landline instead of cell phone whenever possible, but make sure it’s not a cordless phone. Through a 2010 study (Havas M.) researchers found that exposure to cordless phone radiation can cause increased or irregular heart beats and other disturbances of HRV. Stating that, “forty percent of the subjects experienced some changes in their HRV attributable to digitally pulsed (100 Hz) [microwave] radiation,” the researchers also noted that, the “dramatic changes observed in both heart rate (HR) and HR variability were associated with [microwave] exposure at levels well below (0.5%) federal guidelines in Canada and the United States (1,000 microW/cm2).”

4. Avoid Pollutants and Toxins

Air pollution is associated with reduced heart rate variability, so you’ll want to avoid smoggy or high-traffic areas as much as possible. Toxins such as phthalates and bisphenol A (BPA), which are common compounds used in plastics, are linked to low HRV, too. Avoid canned foods (the linings contain BPA) and drink your water out of glass bottles or containers. Stay away from plastic containers as much as possible.

5. Listen to Music

Relaxing to soothing music helps deepen your breathing, which positively affects your ANS and thus heart rate variability. A caution: Don’t listen to heavy metal music if you’re concerned about heart health. Research shows that heavy metal music will lower your HRV. Tranquilizing music such as slow-tempo classical compositions is best. But pick music that you enjoy and truly relaxes you. If you don’t like classical music, for example, you won’t enjoy it, and it won’t likely have a healing effect on you. Maybe for you, reggae music – the beat of which is said to most closely resemble the human heart beat – is instead the more relaxing choice.

6. Get Help for Depression

The connection between heart disease and depression is well known, and a history of major depression is considered a powerful independent predictor of future cardiac events. One reason is that depression is associated with a lowered HRV. Counseling, regular exercise, and proper nutrition are all complementary therapies that can help you banish the blues and improve your heart rate variability.

7. Take Targeted Nutritional Supplements

As far as supplementation goes, my standard recommendation for HRV and overall cardiac health daily is multivitamin/mineral foundation program with 1 – 2 grams of fish or squid oil, bolstered each day by Coenzyme Q10 (90-150 mg); L-carnitine (500-1000 mg), D-ribose (5 gm); and Magnesium (400 mg). Vitamin B12 has been shown in research to increase HRV, particularly if you’re following a vegan or vegetarian diet. In either case, take 100 mcg or more, up to 750 mcg daily.


© Stephen Sinatra, MD. All rights reserved.

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