A few years ago, my fitness tracker started showing me something called HRV. I had no idea what it meant. The number would go up and down and I couldn't figure out why I should care.
Then I started learning about stress, recovery, and the nervous system. Suddenly HRV made sense. Now it's one of the first things I check each morning.
HRV in Plain English
Your heart doesn't beat like a metronome. There's actually slight variation in the time between each beat. If your heart rate is 60 beats per minute, the beats aren't perfectly spaced one second apart. One gap might be 0.9 seconds, the next 1.1 seconds.
That variation is your HRV. And counterintuitively, more variation is actually better.
High HRV means your heart can quickly speed up or slow down in response to what your body needs. It's a sign of a flexible, resilient nervous system.
Low HRV means your system is more rigid. Your body is having trouble adapting. This often happens when you're stressed, tired, sick, or overtrained.
Why Should You Care?
HRV has become popular because it's one of the few metrics that gives you a window into your nervous system. Most health numbers (weight, blood pressure, cholesterol) change slowly over time. HRV changes daily and reflects how you're doing right now.
Research has linked higher HRV to:
- Better stress resilience
- Improved athletic performance and recovery
- Lower risk of cardiovascular disease
- Better emotional regulation
- Longer lifespan
Lower HRV is associated with:
- Chronic stress and burnout
- Anxiety and depression
- Poor sleep
- Overtraining
- Illness (often before symptoms appear)
I've noticed that my HRV drops before I feel sick. It's like an early warning system.
The Vagus Nerve Connection
Your vagus nerve is directly responsible for the "high" part of HRV. When your vagus nerve is active, it slows your heart rate and creates more variability between beats.
This is why improving your "vagal tone" (the strength of your vagus nerve) increases your HRV. The two are closely linked.
Breathing exercises, meditation, and other vagus nerve techniques work partly because they increase HRV. And tracking HRV is one of the best ways to see if those practices are actually working.
How to Track HRV
You have a few options:
Wearables. Apple Watch, Oura Ring, Whoop, Garmin, and others all track HRV. Most measure overnight or take morning readings. This is the easiest approach.
Chest straps. Polar and Garmin make chest straps that give more accurate readings. Good for serious athletes or if you want precise data.
Phone apps. Apps like HRV4Training use your phone's camera to measure HRV. You put your finger over the camera and it detects your pulse.
I use an Oura ring and check my morning readings. It took me a few weeks to establish my baseline and understand what my normal range looks like.
What's a "Good" HRV?
This is where it gets tricky. HRV varies massively between people. Age, genetics, fitness level, and other factors all play a role.
A healthy 25-year-old athlete might have an HRV of 80+. A healthy 55-year-old might be around 30-40. Both could be perfectly normal for them.
What matters more than the absolute number is:
Your personal baseline. What's normal for you?
Trends over time. Is your average going up or down over weeks and months?
Daily variation. Big drops from your baseline often mean something is off.
I stopped comparing my numbers to other people and started comparing them to my own history. That's when HRV became useful.
What Affects HRV?
From my own tracking, these things lower my HRV:
- Poor sleep (biggest factor for me)
- Alcohol (even one or two drinks)
- High stress days
- Getting sick
- Intense exercise without enough recovery
- Dehydration
- Eating late at night
These things raise my HRV:
- Consistent sleep schedule
- Morning breathing exercises
- Regular moderate exercise
- Spending time outside
- Social connection
- Days off from intense training
Your patterns might be different, but tracking helps you figure them out.
Using HRV to Guide Your Day
Some people use HRV to decide how hard to train or how much to push themselves. If your HRV is way below your baseline, maybe today isn't the day for a hard workout.
I don't take it that far, but I do pay attention. If my HRV has been low for several days, I take it as a sign to ease up and focus on recovery.
It's also useful for seeing if lifestyle changes are working. When I started doing breathwork regularly, I watched my average HRV climb over about six weeks. That was motivating.
Common Mistakes
Obsessing over daily numbers. Day-to-day variation is normal. Don't freak out over one low reading. Look at trends over a week or more.
Comparing to others. Your numbers are your numbers. Someone else's baseline is irrelevant to your health.
Measuring at different times. HRV changes throughout the day. For consistent tracking, measure at the same time (morning is best for most people).
Not accounting for context. A low reading after a hard workout or a late night is expected. That's not a problem. It's just information.
Getting Started
If you're new to HRV:
- Get a device or app that tracks it
- Measure consistently (same time, same conditions)
- Collect at least 2 weeks of data before drawing conclusions
- Look for patterns between your HRV and lifestyle factors
- Focus on trends, not single readings
I wish I'd understood HRV earlier. It's given me a way to actually see if my stress management practices are working instead of just hoping they are.
If you want to improve your HRV, the techniques that work are the same ones that improve vagal tone. VagusVital has programs specifically designed for this, with 5 free to start. The app also includes mood tracking so you can see patterns over time. Check it out and track how your HRV responds.
