Heart Rate Variability: Monitor This Metric to Upgrade Your Health
With the wide variety of wearables on the market today, we have the ability to track our steps, sleep, exercise, heartbeat — even our calorie expenditure. And with this influx of health-focused technology, we’re more curious than ever about tracking metrics that give us further insight into our current state of health.
Heart rate variability, commonly referred to as HRV, is one of these metrics, and it has the potential to communicate volumes about our physiological and mental response to stress. If you’re interested in ways to take your health to the next level, monitoring this critical metric should be at the top of your list.
What is Heart Rate Variability?
HRV is a measure of the time interval between two consecutive heartbeats, recorded in milliseconds. A healthy heart doesn’t beat every second on the second or at predetermined intervals like a metronome. Instead, a healthy heartbeat is dynamic, ever-changing, and so is HRV.
In most cases, you won’t be acutely aware of changes in your HRV because any variation is slight — it’s measured in fractions of a second, after all. That said, even slight variations are extremely telling when evaluating your overall health.
How Do You Measure HRV?
Because you can scarcely discern variations in your HRV, you cannot simply take your pulse and calculate a reading. Instead, there are two primary ways you can measure your heartbeat: wearable tracking devices and an electrocardiogram (ECG), which is considered the gold standard of tracking HRV.
Wearable Devices: Commercially available, wearable devices employ photoplethysmography (PPG) to measure inter-beat intervals, also called IBIs. These devices typically work by detecting waves of blood flow from one part of your body to another, and using that information, they calculate your IBI.
ECG: ECG-based methods measure the span between R peaks in your heartbeat. When you view an on-screen ECG measurement, the R peak is demonstrated by the highest central point in the graph. The distance between these R peaks is known as the R-R interval.
Both devices ultimately deliver an accurate measure of your HRV. In fact, researchers have confirmed a high degree of correlation between wearable PPG measurements and ECG recordings. And since heading to your doctor every day just to monitor your heart is unrealistic, wearable technology is a practical alternative for measuring HRV.
A few brands of wearable devices to consider include the following:
- Oura Ring
- Elite HRV
- BIOPAC HRV
Why Should You Care About Your HRV?
When it comes to your health, heart rate variability knows you better than you know yourself. Knowing your HRV is like opening a window to your nervous system, revealing the interconnect between your brain and cardiovascular system and how they communicate.
A generally low HRV — minimal variations in the span between heartbeats – indicates chronic stress, low self-regulatory capacity, and even ongoing system decline. A higher HRV reflects a healthy cognitive-cardiovascular relationship, meaning your body is well-adapted to handle stress.
To understand how HRV reflects the health of your cognitive and cardiovascular systems, let’s look at the autonomic nervous system — the system that governs heart rate variability.
Heart Rate Variability and Your Autonomic Nervous System
Your autonomic nervous system (ANS) regulates the bodily systems that keep you alive — even when you’re not actively thinking about them. The ANS consists of three parts: the sympathetic branch, the parasympathetic branch, and the enteric branch. When monitoring HRV, you’ll be looking primarily at the sympathetic and parasympathetic systems.
The sympathetic branch of your autonomic nervous system, or SNS, regulates what is often referred to as your “fight-or-flight” response to stressful situations. In the context of stress, this can mean emotional, mental, or physical stress, such as exercise.
When the SNS activates, it increases heart rate, thereby decreasing heart rate variability. When your heart beats faster, the interval between beats automatically becomes shorter and more constant.
The parasympathetic branch, or PNS, acts as the counterbalance to the SNS. It’s often referred to as the “rest-and-digest” system because it restores homeostasis and regulates bodily functions like immunity and digestion.
After the SNS activates and the “fight or flight” response is over, the PNS works to bring your body back into balance. It helps you recover by lowering your heart rate, thereby increasing heart rate variability. This back-and-forth regulation between the two systems allows your heart to respond appropriately, depending on the situation at hand.
What Does a Healthy HRV Look Like?
In a healthy individual, HRV fluctuates according to system demand. It should always be higher during relaxing activities like sleep, meditation – even binge-watching your favorite show. Since your parasympathetic nervous system kicks in during these types of activities, your heart rate should decrease, resulting in a higher HRV.
Conversely, HRV should decrease in response to stress to help your body respond appropriately to increased systemic demand. If you’re crushing a workout or have a big deadline at work, you can expect your HRV to be relatively low. However, when your sympathetic nervous system stops firing, and you’ve had a chance to let your body calm down, your HRV should naturally rise.
If you’re chronically stressed, or your body is experiencing some kind of systemic overload, your HRV will be chronically low — even when you’re resting. This phenomenon can take a significant toll on both your mental health, physical well-being, and even your immune function.
Who Should Monitor HRV?
HRV monitoring is for everyone! Keeping tabs on your heart rate variability gives you information about your body that no other source can deliver.
If you’re an athlete or fitness enthusiast searching for ways to take your performance to the next level, HRV monitoring can help you make the appropriate adjustments to your routine. By monitoring your HRV, you can tweak your training, rest, recovery practices, and even your nutrition to help your body thrive. If you notice a significant, lasting drop in your HRV, you’ll know you’ve overloaded your body and need to take a break.
For non-athletes, HRV monitoring can help you tailor your physical activity, rest, sleep, mindfulness practices, and nutrition to achieve lasting health. Monitoring your heart rate variability will help you understand your body’s response to stress. As you learn how stress affects your entire system, you can make the necessary adjustments to improve your cardiovascular health, immune function, and even your mental well-being.
Do You Monitor Your Heart Rate Variability?
If you’ve tried monitoring your HRV, what was your experience? Do you want to get started, but you’re not sure which devices have proven effective? Let us know and we’ll be happy to get the discussion started!