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From wearable tech like the Apple Watch to heart rate-based training classes like spin and Orange Theory, using heart rate monitors outside of the doctor's office has become mainstream. Increasingly, people are seeing the benefit of understanding their heart rate (and more specifically, heart rate variability) as a tool for tracking health and getting the most out of a workout routine. Early patent reports even show the next generation of Apple AirPods are likely to include biometric ear sensors for measuring heart rate, electric activity in the heart, and blood flow.

So, what’s up with everyone wanting to keep tabs on their heart all of a sudden? Here’s the lowdown on why and whether you should be doing it, too.

The Value of Knowing Your Heart Rate

Even if you don’t own a fitness tracker, you’ve likely seen similar heart rate data on treadmills, spin bikes, or similar exercise machines at the gym. Based on heartbeats per minute (HR BPM), your physical fitness is broadly categorized into different exercise “zones,” which may include resting, warm-up, fat burn, endurance, and maximum heart rate. Ideally, fitness trackers and exercise machines monitor your HR BPM to give you a general idea of which energy zone your body is in.

Using Your Heart Rate to Track Your Fitness Level

Heart rate data is an empowering tool that can help you be more aware of your heart health and overall fitness level. A study published in the Annals of Internal Medicine earlier this spring found that while the heart rate monitor in your fitness tracker isn’t as accurate as medical devices or the standard chest strap, they are accurate enough for most consumers’ basic fitness data needs.

Dr. Nisha Jhalani, a cardiologist at NewYork-Presbyterian: Columbia University Medical Center, told CNN, “Oftentimes, our perceived activity is much more than the actual time we spend moving, especially people whose jobs involve sitting at a desk for hours at a time.” Dr. Jhalani says it’s good for people to see their heart rates at rest and during exercise. “Low resting heart rates, in the 60 to 70 BPM range, are considered generally healthy. High resting heart rates, especially when close to 100 BPM or higher, can be a sign of high stress levels or other medical conditions,” Dr. Jhalani said. Plus, how quickly your active heart rate returns to your resting rate after exercise says a lot about your cardiopulmonary fitness. The quicker your heart rate returns to normal, the stronger your lungs and heart.

To keep general tabs on your heart rate or to use it to motivate you to work harder during exercise, many wearable fitness trackers work just fine. But a growing body of research shows the heart has much more insight to offer us than we thought.

A Deeper Metric to Measure Your Overall Well-Being

Heart rate variability (HRV) is a deeper layer of data that measures the changes (variables) in the length of time between heartbeats. HR BPM gives you a count of heartbeats per minute, whereas HRV measures whether it takes 1 second between heartbeats or 0.5 seconds, 1 second, 1.5 seconds, and then 0.75 seconds, etc. between heartbeats.

HRV sensitivity fluctuates in response to internal and external stressors, from how much we’re sleeping and exercising to our mood and digestion of food, alcohol, coffee, etc. Research shows it’s healthier to have an increased HRV (more time variability between heartbeats) at resting HR and a lower HRV at active HR. Decreased HRV is a plausible link between depression and heart attacks and is consistent with symptoms of panic attacks and anxiety. Low HRV is also associated with inflammation, heart disease, diabetes, and high cholesterol. A 2017 physiological study found that HRV could even serve as an index of a healthy person’s cognitive abilities; reduced HRV was associated with poor performance of activities that simulated day-to-day tasks.

Compared to basic HR monitors, HRV monitors like the Lifetrak ZoomHRV—the first HRV body computer—can give more precise biometrics of your every movement, minute slept, and calorie burned because it uses more precise heart rate data. Most popular fitness trackers still aren’t able to track HRV, though Wareable reported that the FitBit Charge 2 and Garmin Vivosmart 3 recently added HRV monitoring to their devices.

HRV tracking is transforming how wearable tech measures not just physical fitness but also mental and emotional health. How access to this data will influence our lifestyle choices—like what we eat or whether we make time for meditation—needs further research. Until then, it’s a good idea to keep a pulse on what’s normal for your heart rate and how it changes throughout your day. At the very least, this info can motivate you to make better decisions about how you exercise, sleep, and manage stress levels. When it comes to caring for our long term health, we’d take that investment in a heartbeat.

Photo Credit: Corinne Kutz