An Overview of Heart Rate Variability
Heart rate variability is a physiological parameter which can provide important information to guide our pursuit of health, wellbeing, and sustainable high performance.
Dr. Darin Davidson partners with Learner+, a CME/CE reflective learning platform for healthcare providers. For the opportunity to reflect on this article and earn CME/CE credits, Launch here. Check out all past articles which are also eligible for reflections and CME/CE credits.
For downloadable, actionable strategies and tactics to leverage biology in the pursuit of health, wellbeing, and sustainable high performance, visit the resource store, Launch here. Chapters are arranged by topic so those of interest can be selected and each are also eligible for reflections and CME/CE credits through Learner+.
Heart rate variability (HRV) is a commonly measured and important physiological metric. It is necessary to understand what this measures, represents, and, most importantly, how to incorporate this information into our daily practices. This parameter can be a significant contributor to our pursuit of health, wellbeing, and sustainable high performance.
A recent article in this series described the implementation of wearable technology into our regular routines. The importance of acknowledging the information provided by these devices without allowing it to drive our biological states was emphasized. Amongst the measurement devices, HRV is one of the more important and commonly measured parameters. This article will focus on an understanding, at least in general terms, of what HRV is and its uses and limitations. Ultimately any physiological metric which we measure should be incorporated within our overall practices, including implementation of strategies and tactics in the pursuit of health, wellbeing, and sustainable high performance.
Heart rate variability describes the variation in the timing of our heartbeats. A common misconception is that our heart beats at a regular interval. In actual fact the time between successive heartbeats is somewhat variable, although this variation is not consciously perceptible. The measure of HRV in essence is a measure of the differences in time between successive heartbeats measured over time. It is important to understand that within the overall concept of HRV, there are various parameters which can be measured. The details of these are beyond the scope of this article. There are numerous excellent resources which detail these different measurements.
Because of the different methodologies for measuring HRV as well as the different parameters which can be analyzed, it is important that if we are to incorporate HRV within our overall practice that we utilize the same device over time. This ensures that our HRV is being measured, interpreted, and analyzed in a similar fashion at each reading so that we can compare HRV values over time. If different devices or methodologies are utilized, then it is not possible to reliably compare the information.
At its core, HRV provides the currently most accessible and best measure of nervous system recovery. It is a measure of the strength of our nervous system recovery at baseline as well as in response to stressful events and activities. In situations in which we have high sympathetic nervous system activity, our heart rate will increase and simultaneously the timing between successive beats will decrease. This is measured as low HRV. In contrast, when we have greater parasympathetic nervous system activity, there will be increased variability between successive heartbeats. This results in an increased measure of HRV.
The greater our HRV, the greater is our nervous system resilience, flexibility, and degree of recovery. By measuring at one point in time, we gain information regarding these variables at the time of measurement. A broader perspective can be obtained by measuring over time. In so doing we gain a more longitudinal understanding of our overall degree of nervous system resilience, flexibility and recovery.
It is important to note that a different, yet related measure, specifically respiratory sinus arrhythmia, is perhaps a better measure of parasympathetic nervous system activity and, therefore, nervous system flexibility and recovery. This measure determines the differences in timing between heart beats on account of differences in our breathing patterns. While this may be a better measure of overall nervous system recovery, its measurement is more elusive and difficult to capture outside of a laboratory setting than is HRV. For this reason, HRV is currently a more commercially accessible and available measurement tool for assessing nervous system recovery.
With an understanding of the significance of HRV in mind, it becomes possible to turn attention towards its application. As noted above, the HRV parameter is an indicator of nervous system recovery. This understanding leads to the recognition that HRV is not an endpoint in and of itself. Rather, it is a surrogate measure and indicator of our nervous system recovery. Ultimately, this is a piece of information which should be incorporated within our broader awareness of our overall biological state and level of recovery.
Heart rate variability can be used to measure our response to training various skills within the Practices of the Healthcare Athlete. For instance, while we are doing breathing practices, we can simultaneously measure our HRV to see the impact of different breathing patterns on our nervous system, as measured by HRV. In addition, when measured longitudinally, we are able to see changes in our overall baseline nervous system recovery and response to various stimuli on account of regular practices within our daily routines. In essence, this can provide an objective measure, not only of our baseline state prior to initiating a training program, but also of our physiological response to that program.
Another consideration within the implementation of HRV is to use this measure as a piece of information to help guide our activities, where possible, on the basis of our level of recovery. For instance, on days in which our HRV measurements are increased, indicating a higher level of recovery, we may choose to initiate higher demand training activities. Conversely, in response to lower HRV measurements, we may choose to limit the degree of intensity of our training to reflect the fact that our recovery is decreased.
It is also important to acknowledge the limitations of HRV measurement. As noted above, different devices may measure, interpret, and/or analyze the physiological parameters in different ways leading to different representations of HRV. It is therefore important that we utilize the same device on a consistent basis so that we can track and compare the measures over time.
In addition, as discussed in the previous article related to implementation of wearable technology in general, HRV is a data point which can provide useful information, but it becomes important that we not over-index on the actual measures. If an HRV measure indicates lower recovery, for example, it is important that we not perseverate over this and allow it to become a cue towards biological state shifts into activated, attacking, anxious, overwhelmed, or shutdown states. Rather, it is more useful to consider HRV as a data point and utilize the information without becoming overly reactive to it.
Ultimately, HRV is an important metric, however it is not an outcome in and of itself. The purpose of training mind-based and body-based skills is to promote health, wellbeing, and sustainable high performance. The objective of these practices is not to increase HRV in and of itself. It is important to remember that HRV is a surrogate measure and indicator of nervous system recovery. As such it can be a useful compliment to training the mind-based and body-based skills, strategies, and tactics.
Within the Practices of the Healthcare Athlete, development of increased nervous system flexibility and strengthening of anchored and grounded states is a foundational objective. Heart rate variability can be an important measure of the degree to which we are increasing each of these nervous system outcomes. For this reason, it is advised that measurement of HRV be incorporated within daily routines and practices but not become an emphasis. Heart rate variability should be incorporated as a piece of information which is considered along with other sources of information, most importantly, our awareness of our overall biological state.
In the embodiment of the Practices of the Healthcare Athlete, it is important that we pay attention to recovery. Heart rate variability can provide important information in this regard. Again, it is important to emphasize the importance of not over-emphasizing HRV values themselves, but rather considering the data in the context of all other available information. Ultimately our goal is to promote health, wellbeing, and sustainable high performance and HRV is one of several sources of information we can obtain to guide us in this pursuit.
To learn more, including about polyvagal informed coaching for healthcare professionals and others in high demand domains, please visit www.darindavidson.com.
Dr. Darin Davidson partners with Learner+, a CME/CE reflective learning platform for healthcare providers. For the opportunity to reflect on this article and earn CME/CE credits, Launch here. Check out all past articles which are also eligible for reflections and CME/CE credits.
For downloadable, actionable strategies and tactics to leverage biology in the pursuit of health, wellbeing, and sustainable high performance, visit the resource store, Launch here. Chapters are arranged by topic so those of interest can be selected and each are also eligible for reflections and CME/CE credits through Learner+.