Heart Rate Variability: What is it and how to use it to monitor health?
Last month we highlighted the importance of tracking your resting heart rate. This month we are touching on a more unfamiliar topic, Heart rate variability (HRV). Heart rate variability is the physiological phenomenon of variation in the time interval between heartbeats. There is constant variation in a normal, healthy heart. This variation occurring beat to beat is typically not something we are aware of.
Why monitor HRV?
HRV can be used to monitor sleep, recovery, performance, and overall health. Tracking HRV can be a great tool to motivate behavioral change through diet and exercise. It can also provide useful knowledge to coaches and performance teams in regard to making correct training and coaching decisions.
The significance of change in HRV.
HRV is regulated by the autonomic nervous system (ANS), and its sympathetic and parasympathetic branches. The parasympathetic side is characterized as the “rest-and-digest” system that allows the body to relax and recover. The sympathetic branch is our “fight or flight” mechanism that activates stress hormone production and increases the heart’s contraction rate and force.
In a normal, healthy situation, HRV should increase during relaxing activities. On the other hand, HRV decreases during stress, when elevated sympathetic activity helps the body keep up with the demand. HRV is typically higher when the heart is beating slowly and lowers when the heart starts to beat faster during periods of stress or exercise.
The HRV level changes naturally from day to day. These changes are brought on by level of activity, life situations and changes, and often times, work-related stress, etc. If a person is chronically stressed or overloaded the interplay between the parasympathetic and sympathetic braches can be disrupted, and the body can get stuck in a sympathetically dominant fight or flight state, even at rest. This is very taxing on the body and can result in various physical, mental, and emotional health problems.
How to track HRV.
Reliable HRV tracking and monitoring requires accurate measurement of each heartbeat and the time between beats. The easiest and most affordable way to check HRV is to buy a chest strap heart rate monitor. Popular brands include Garmin, Polar, and Wahoo Fitness and download a free app (Elite HRV) to analyze the data. The chest strap monitor tends to be more accurate than wrist or finger devices. Another popular company with wearables used to track HRV is Whoop (https://www.whoop.com/). Check your HRV in the mornings after you wake up, a few times a week, and track for changes as you incorporate lifestyle changes. Consult your healthcare provider and team to see if tracking your HRV may be beneficial for you!