Everything You Should Know About Heart Rate Variability (HRV)
- Mar 1, 2022
- 3 min read
Updated: Apr 27
“HRV is the single greatest non-invasive proxy that we have for measuring the adaptations of the nervous system.” — Dr. Jay Wiles
What is HRV (and why should you care)?
Heart Rate Variability (HRV) is the variation in time between each heartbeat, measured in milliseconds.
It might sound small—but it’s incredibly powerful.
HRV reflects how well your autonomic nervous system is balancing two key systems:
Sympathetic (fight or flight) → mobilizing energy
Parasympathetic (rest and digest) → conserving energy (think: parachute slowing you down)
At its core, HRV is a signal—a real-time window into how your body is responding to stress, recovery, and everything in between.
Why HRV matters for health, performance, and longevity
HRV tells you one thing really well:
👉 How adaptable your body is
Higher HRV (relative to you) → better resilience, recovery, and cardiovascular health
Lower HRV → your system is under strain (physical, mental, or both)
Your nervous system is constantly managing millions of processes to maintain homeostasis—your body’s ability to stay stable despite changing conditions.
HRV is how we measure how well that’s going.
The surprising truth about your heartbeat
Your heart is not supposed to beat like a metronome.
If your heart rhythm becomes too consistent, it can signal that your nervous system is overwhelmed and defaulting into a rigid, protective state.
👉 In other words:More variability = more flexibility = healthier system
What HRV actually represents
When you think about HRV, think:
Adaptation → how well you respond to stress
Resilience → how quickly you recover
Flexibility → how smoothly your system shifts gears
This is why HRV is such a powerful metric—it reflects both stress AND recovery, not just one side of the equation.
Why you should NEVER compare your HRV to others
Comparing HRV scores is one of the biggest mistakes people make.
Your baseline HRV is heavily influenced by:
Non-modifiable factors:
Age (HRV naturally declines, especially 40–50+)
Genetics
Sex
That’s why a professional athlete’s HRV might look very different from yours—and that’s completely fine.
👉 The only HRV that matters is your own trend over time
What actually matters: your HRV trends
Instead of focusing on a single number, look at:
Consistency over time
7-day rolling averages
Coefficient of Variation (CV) → how much your HRV fluctuates day-to-day
A stable, gradually improving HRV trend is a strong signal your body is adapting well.
What improves HRV (the big levers)
If you want to improve HRV, focus on what actually moves the needle:
1. Sleep (the foundation)
Sleep is the ultimate repair system for your nervous system.
Think of it as:👉 The canary in the coal mine
If your sleep is off, your HRV will reflect it—almost immediately.
2. Exercise (especially VO₂ Max work)
Improving cardiovascular fitness is one of the most powerful ways to raise HRV.
Aerobic training
Interval work
Consistent movement
All improve how efficiently your body handles stress.
3. Downregulation (calming the nervous system)
This is where most people fall short.
You need intentional time where your body shifts out of stress mode.
Examples:
Meditation
Sitting quietly
Time in nature
Controlled breathing
The game changer: Resonance Breathing
One of the most effective tools for improving HRV is resonance breathing.
How it works:
4.5–6.5 breaths per minute
10 minutes per session
4–6 days per week
What happens:
Improves HRV
Lowers blood pressure
Increases vagal tone (parasympathetic activity)
👉 Consistent practice can create real, measurable nervous system changes in as little as 4–12 weeks
Pro tip: Use it before bed
Doing resonance breathing before sleep can:
Improve deep sleep
Reduce nighttime wake-ups
Accelerate recovery
Final takeaway
HRV isn’t just a number—it’s feedback.
It’s your body telling you:
How stressed you are
How well you’re recovering
How adaptable your system is
If you want to improve your health, performance, and longevity:
👉 Train your body to handle stress👉 Give it time to recover👉 Track the trend—not the score
Because at the end of the day…
A resilient nervous system is a resilient life.
Get After It!!
-Austin
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