Heart rate variability (HRV) is the difference in time between beats and has been used by health professionals for decades to monitor heart problems. With technological advances HRV has started to be studied and used to monitor and track other diseases and health conditions, track physiological and psychological stress, monitor recovery and for earlier detection of heart problems.
With so many potential applications, HRV has a broad audience of those who would benefit from tracking. The good news is that with recent advances in both hardware and software, tracking HRV has become an affordable option for anyone interested in using it. In fact many fitness trackers already have the technology to track your HRV.
While most people will likely be interested in using it to try and personalize their training and recovery times which is something that many athletes and sports teams are doing, there’s also opportunities to contribute data to a worldwide study hoping to better detect heart arrhythmia with the hope of saving lives.
A Deeper Dive
To measure HRV the time between beats is measured and is recorded as either the R-R interval or a inter-beat interval (IBI). The difference between these intervals is then calculated to give HRV and can be done in numerous different ways. While it seems strange, your heart should be beating somewhat erratically and not like a metronome, so a higher HRV is better. The reason for this is because your heart rate is controlled by your autonomic nervous system. The two branches of your autonomic nervous system are the sympathetic and parasympathetic systems and have opposing responsibilities. The sympathetic or “fight or flight” system is centered in our adrenal medulla and uses the chemical adrenalin to tell our bodies that we are in a stressful situation, accelerating and constricting the heart. When we are working out, the sympathetic system is in full force, increasing your heart rate and decreasing HRV. Meanwhile the parasympathetic branch is centered in the adrenal cortex and uses neurotransmitters as its chemical mediators. The parasympathetic branch slows and relaxes the heart and when at rest is slightly more dominant and gives a higher HRV.
After a hard workout while your pulse may quickly return to normal, your HRV may remain low for awhile as your body recovers. Low HRV readings can also be caused by psychological stress, illness and other factors. As the body recovers, HRV increases, indicating you’re ready for the next workout or even telling you your full prepared for that stressful meeting on the agenda today!
How To Track Your HRV?
Obtaining an HRV reading takes about a minute and is usually done first thing in the morning. It requires an HRV app and some way of measuring heart rate, either using a chest monitor or a smart watch. The app will guide you through the process and provide you with a final reading. A high reading indicates your body is in a good state to tackle stress like strenuous exercise. A low number suggests that your body is overly stressed or fatigued. In this situation it might be advisable to have a lighter workout or try to lower your stress levels using meditation or other means. By understanding where you are in the recovery spectrum you are better able to manage stress and avoid under or over training.
Seems simple enough but it takes time to understand and interpret your individual readings and then tailor them to your own workouts. Every individual will have a different range of readings, based on age, overall fitness, mood, drugs and even body position. That means that you will likely require a number of readings to establish your baseline. This could take weeks of monitoring and correlating workouts and other lifestyle choices to readings. Once a baseline is established you can balance recovery and workout intensity based on your particular HRV reading.
WHERE TO START
Checking the Google Play store or the App Store you will find hundreds of apps that have something to do with HRV. The good news is that most are free. Almost all will have advanced algorithms and user friendly interfaces making it pretty easy to get started. Some of the better rated ones that I found include ithlete, Elite, and the BioForce HRV kit. For those interested in joining a heart study try cardiogram.