Why is heart rate variability important?
Heart rate variability can be used to obtain information regarding a person’s internal physical and emotional state. This information depends on the clinical setting. For example, in a neonatal care unit change in HRV can be used to predict sepsis before other clinical signs are observed. In patients who have had a heart attack HRV can be used to warn is another heart attack is likely. In a stressful situation HRV can give information on how a person is responding to the stress.
Over the past 20 years and in thousands of sessions I have used monitoring equipment to follow the beat-to-beat heart rate of my patients. From this extensive experience I have learned some key points:
- Heart rate variability is particular to each individual. There is no one heart rate variability that is “good” for everyone. While there are some generalities the HRV trace is unique to the individual. An HRV trace that is good in one person may not be good in another situation.
- Heart rate variability is related to the context or situation. Since the heart rate responds to physical demands as well as stress the HRV trace can be interpreted reliably only if one knows the context in which the trace was recorded. A trace that is good in one situation may indicate problems in another situation.
- Many changes in the HRV trace are not clinically relevant and need to be ignored.
- Some changes in the HRV trace are important and these changes can appear within seconds. One needs practice to spot these and most programs that analyze HRV do not have the capacity to spot such rapid changes.
How does HRV Team use heart rate variability?
The meaning of a particular trace is related to the speed of the heart rate in beats per minute, the shape of the HRV trace, and the beat-to-beat variability within that trace.
HRV Team displays all of these in real-time for each member of the team or class working with an instructor. This allows an instructor who has appropriate training to identify which team members or students are learning the techniques effectively and which may need more assistance. The instructor can also observe how stress or resilience can resonate among the members of a team and show team members how to help each other be calm and effective under stress.
What do the different colored dots mean?
The dots are colored using symbolic dynamics, a mathematical method used to analyze heart rate and other complex systems. The black dots indicate lower variability. In the same individual and other conditions being equal, the more frequent the black dots the more sympathetic activation. The meaning of the black dots varies significantly depending on the situation. We recommend that you leave the LVI set to 0 unless you are familiar with interpreting heart rate variability.
What heart rate monitors does HRV Team work with?
HRV Train will work with any monitor that sends RR data using standard Bluetooth Low Energy, BLE, protocols. It has been tested successfully with the Zephyr HxM Smart, the Polar H7 and H10, and the FirstBeat chest strap. The Garmin, Sony and Fitbit monitors appear to use a proprietary protocol and will not work with HRV Trace.
Only the Zephyr HxM Smart will send activity levels to the app. The other monitors do not have that capacity.
My heart rate seems much more erratic than it should, what does that mean?
The most common cause of an erratic heart rate is a poor connection to the chest strap. We have had some difficulties with the Zephyr chest straps giving more inaccuracies after 20 hours of use. Replacing the battery fixes the problem.
We have not had any difficulties with the app misreading the data sent. Every instance of questionable data has been from the chest strap not working properly, a low battery in the monitor, or too great of a distance for clear BLE communication.
If you are concerned about your heart rate then please see a medical professional.
I am having problems connecting to the heart rate monitor. How do I fix that?
Make sure that other iOS devices that might connect to the heart rate monitor are off or out of range. Also make sure that you do not have other heart rate monitors active that could be connecting to the app.
When someone has used multiple heart rate monitors and various other apps on their iOS device they have had to turn bluetooth off in their device settings, then put on the monitor, start the app, and then turn bluetooth on. Once the app has paired with a heart rate monitor it will remember that and connect automatically if the heart rate monitor is on and in range.
My activity level is not changing even if I am moving around. What is wrong?
Only the Zephyr HxM Smart transmits activity data. The other monitors do not and no activity data will be recorded.
What is the accuracy of the heart rate and RR interval data?
The app records data using the accuracy of the heart rate monitor. The Polar and FirstBeat monitors use 1 msec accuracy for the RR interval data. The Zephyr monitor uses 4 msec accuracy.
HRV Team 