HEART RATE VARIABILITY:
PART 2.

Resting Heart Rate & HRV as Fitness Indicators. 

When your heart rate goes down, each heartbeat is more effective. When your HRV is higher, there is more capacity to allocate resources towards exercise. HRV naturally goes down while you’re exercising hard. The more you’re not sympathetically dominating, the more room there is for sympathetic activities to come in and dominate.

What Things Affect HRV? Activity level, stress, fatigue, illness, hydration, alcohol, etc. It is one of the most sensitive metrics when talking about fitness, which makes it powerful and tricky as HRV changes a lot daily and within the day.

HRV Variance.

You want to send the right signal to your body at the right time based on what you need to do, so your goal is not to have maximum HRV every second of every day. Resources need to go to stuff. So if you start to understand how different things affect your HRV individually, you can start to manipulate the timing of these things relative to moments you need to peak in sport and play.

The WHOOP Version Tracks HRV During Sleep

Previously, the norm for top researchers like Daniel Plews and Martin Buchheit was to take HRV first thing in the morning, but they admittedly did that for convenience, not because it was functional. New research now captures it during slow-wave sleep (SWS). During slow-wave sleep, you’re the most dead to the world, so it is the best time to compare HRV on a night-by-night basis and get a clean signal.  

Your Recovery (Recovery Score) is Primarily based on HRV Numbers.

The metric also uses resting heart rate (rhr) and sleep to some extent.  

Day-to-Day Fluctuation. 

Variability in heart rate variability is a good thing. Being “in the red” can be beneficial sometimes. “Functional overreaching” is what it can be called, followed by constructively resting.

Track your HRV Trends Over Time.

Track yourself and not others. It’s you vs you, and what is your HRV today relative to your baseline. It’s best to analyze it after a normal steady week where you start to establish a trend. For example, if you’re taking steps to improve your fitness and overall health, over time, you should see a gradual increase in your average heart rate variability.