HRV heart rate variability: A simple explanation

HRV (Heart Rate Variability): A Simple Explanation

By Anu Acharya, CEO, MapmyGenome

I am a gadget freak — especially those that have anything to do with health. So I was quite excited with the HRV (heart rate variability) feature on the Apple Watch. But what does that number actually mean? Let me explain — and note that there is no substitute for a true healthcare professional and medical-grade devices, so please do consult a cardiologist if you have a family history of heart disease.

What Is HRV?

Heart rate variability is the variation in the amount of time between heartbeats. Counterintuitively, a higher HRV is generally a good thing. Here’s why.

Your heart is connected to your brain and nervous system through the autonomic nervous system — which has two parts:

• Sympathetic nervous system — the “fight or flight” system; increases heart rate and blood pressure in response to stress or danger

• Parasympathetic nervous system — the “rest and digest” system; slows the heart rate and promotes recovery and relaxation

HRV reflects how well your body can switch between these two systems — how adaptable you are. As Charles Darwin said: “It is not the strongest of the species, nor the most intelligent that survives; it is the one most adaptable to change.”

What Does Your HRV Tell You?

• High HRV — your body is adaptable, resilient, and well-recovered; associated with good cardiovascular fitness and stress resilience

• Low HRV — can signal underlying conditions like hypertension, depression, or diabetes; associated with high resting heart rate and reduced resilience

As one grows older, HRV naturally tends to decline. But it can be improved through regular exercise, good nutrition, adequate sleep, and stress management practices like meditation and yoga.

The Genetic Angle

Genetic variants influence baseline HRV, cardiovascular risk, and autonomic nervous system function. Understanding your genetic cardiovascular profile can help you and your doctor take targeted preventive action for your heart health.