#61: What Is Heart Rate Variability, and How Can You Improve It?

A normal heartbeat has healthy irregularities. For example, if your heart rate is at 60 beats per minute, that doesn’t mean your heart is actually beating once per second. Instead, there can be several variations, like a 0.8- to a one-second interval between some beats, or 1.1 seconds between others.

This is what we call heart rate variability, or simply HRV.

What is Heart Rate Variability?

HRV indicates the different time intervals between consecutive heartbeats within a specific timeframe. These periods between successive heartbeats, called RR Intervals, are measured in milliseconds. 

These variations are controlled by the body’s autonomic nervous system (ANS), which regulates blood pressure, breathing, digestion, and heart and respiration rate. The ANS has two branches – parasympathetic (rest) and sympathetic (active), and HRV is an indicator if both are functioning well.   

Heart rate variability is also one of the many objective metrics to determine one’s physical fitness and readiness to perform.

How HRV is a Sign of Overall Health and Fitness 

When your HRV is high, this means your body is responsive and your nervous system is balanced. It’s a good sign that you’re capable of adapting to your environment, performing activities at a high level, and functioning at your best. 

In other scenarios, HRV increases during relaxing activities like meditation or sleep, or whenever your heart is beating slowly.

Individuals with high heart rate variability have good cardiovascular conditions, are more resilient and flexible to stress, and have better overall health and general fitness. Likewise, research has linked higher HRV to reduced mortality, improved psychological health, and a better quality of life.

What Does a Lower HRV Mean, Then?

On the other hand, low HRV means that one branch, usually the sympathetic, is dominating and sending stronger signals to your heart to help your body keep up with the demand. This commonly happens during exercise, heavy workload, or stressful activities.

However, if you’re not active but your HRV is still low, this can signal that your body is working too hard – possibly you’re fatigued, dehydrated, sick, or in need of recovery.

Research shows that a low heart rate variability is associated with worsening depression and anxiety, and an increased risk of death due to cardiovascular diseases. Worse, chronically stressed or overworked people have higher stress hormone levels and lower heart rate variability even when resting, which can take a toll on their body and cause serious physical and mental health problems.

How to Measure Heart Rate Variability, and Why it’s Important to Do So

Measuring HRV depends on what technology you use. The most common way is through an electrocardiogram (ECG), where wires are attached to your chest. This detects the “R Wave” in the QRS Complex and calculates the time between these waves.

Likewise, many devices can analyze your heartbeat with a Photoplethysmography (PPG), where the steepest increase in the signal before the peak marks a heartbeat. This method detects the heartbeat by measuring the blood flow from your wrist or ear and then calculating the inter-beat interval (IBI).

Another easy and affordable way to check your heart rate variability is to use a chest strap heart monitor or another kind of wearable that’s able to read your data. Try checking your HRV after you wake up and a few times a week, so you can consistently track your data and assess what changes you may need to make. 

Essentially, heart rate variability can be an indicator of how your lifestyle affects your body and can help you make behavioral changes toward becoming healthier. HRV measurements motivate you to become aware of how you live and think, and how your behaviors impact your nervous system and other bodily functions. 

Knowing your numbers allows you to understand how to healthily respond to stress, as well as enables you to assess how your nervous system reacts to different environments, emotions, thoughts, and feelings.

Do note, though, that HRV is unique for every person and shouldn’t be compared with others. Also, it changes daily based on your level of activity and the workload you require of your body. Lastly, there’s no rule of thumb when it comes to what exactly a “healthy” heart rate variability is since there are so many variables to consider.

How You Can Improve Your Heart Rate Variability

Since it’s a good measure of health, fitness, and performance, many people want to improve their HRV. Here’s how you can do so:

1. Get Some Sleep

Sufficient and high-quality sleep allows you to recharge your nervous system. This is also when human growth hormones are produced, as well as anabolic hormones that are essential for muscle repair and recovery. When you consistently track your HRV, you’ll notice how sleep can positively affect your daily measurements.

2. Practice Slow, Deep Breathing

Yoga, meditation, and other breathing exercises can promote relaxation, reduce stress, and increase concentration. Similarly, try to practice breathing with a 10-second cycle time – breathe in through your mouth for five seconds, and out through your mouth for another five. This can help you feel relaxed, calm, and composed, thus increasing your heart rate variability.

3. Mind Your Diet

When you’re under-recovered, heavily trained, over-fatigued, or stressed – essentially having low HRV – your appetite decreases. This results in poor energy balance and depletion of amino acids, fatty acids, and essential hormones.

As such, it’s important to have a healthy diet with lots of fresh fruits and vegetables. Be sure to consume alcoholic and caffeinated beverages moderately. More importantly, limit your refined carbs and sugars when possible.

4. Train and Recover Properly

Overtraining can cause muscle soreness, stress, and inflammation, thus lowering your heart rate variability.

When you first work out, you must train below your aerobic threshold, so that your body doesn’t negatively react to the immediate high intensity. Once you’ve adjusted, you can pick up the pace or go a notch higher.

Similarly, high-intensity training can cause delayed onset muscle soreness (DOMS), which puts you at risk of injuries if you don’t rest and recover well. That’s why it helps to use electric muscle stimulation devices, like PowerDot, to relieve your pain, tightness, and inflammation.   

PowerDot can help speed up joint and muscle recovery, improve muscle strength and endurance, and prevent injuries from happening. It also increases your blood circulation, improves training results, and reduces inflammation. 

This can help improve your overall health and fitness, enable you to do activities at a high level, and allow you to maintain a higher HRV.

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