The metrics my WHOOP 4.0 band give me every day are invaluable for my health and fitness. Heart Rate Variability (HRV) is one of the first numbers I look at every morning, and it tells me a lot about what my day is going to look like. So what is HRV, how do you know if yours is good, and how can you make it better? Here’s my WHOOP guide to HRV. (Click here for my overall review of the WHOOP 4.0 band.)
What is HRV?
Your heart doesn’t beat like a perfectly calibrated metronome; there are minuscule differences in the time between each heartbeat. Heart Rate Variability (HRV) measures the variability of time between heartbeats. Unlike resting heart rate (RHR), the higher your HRV, the better. Here’s a high-level overview of how it works:
- You have two branches to your nervous system: the parasympathetic (rest and digest), and the sympathetic (flight or flight)
- The parasympathetic system encourages your heart to beat slower; the sympathetic tells it to beat faster
- When the two are in balance, you have lots of variability between heartbeats, because your body is receiving both signals
- When you’re stressed, sick, or injured, your sympathetic system takes over, which decreases your heart rate variability
A higher HRV score means you’ve got more heart rate variability, which means your nervous system is in balance and ready to perform or take on strain. A lower HRV score means your sympathetic (fight or flight) nervous system is taking over with the message, “beat faster, we’re in trouble,” which means you’re less prepared to take on additional strain.
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What’s a good HRV score?
HRV is highly individual, so you really can’t compare your HRV to someone else’s. HRV also decreases pretty substantially as we get older, and “average” ranges reported by WHOOP are broad.
- For a 20-25-year-old, average HRV can range from 50-105
- For a 60-65-year-old, average range decreases to 25-45
- Men tend to have a higher HRV than women
- Elite athletes often have a higher average HRV than normal folks
Instead of comparing your HRV to mine, your spouse’s, or your friend’s, instead use your WHOOP band to determine at an average of your HRV scores, then see how your healthy habits improve your own HRV trends over time.
How to improve HRV
Increasing your average HRV score correlates with improved cardiovascular fitness, resilience, and adaptability. Watching your HRV score and trends can tell you whether your behaviors are helping or hurting your nervous system, health, and fitness. HRV can be improved by paying attention to four critical factors:
1. Balance your training. Use WHOOP’s Recovery score combined with Strain Coach to help you exercise without overdoing it. Moving your body and effectively recovering (you need both) is the key to higher HRV. If you find your Strain is consistently in “over-reaching” territory, it’s likely your HRV will suffer.
2. Prioritize sleep. Sleep is hugely important for health, fitness, and HRV. Use WHOOP’s Sleep insights and healthy sleep practices to help you better regulate wake and sleep times, improve sleep quality, and ensure you get enough sleep to help you recover. Pro tip: Light can also play a role here. Avoid light as best as you can between 10 PM and 4 AM; keep your bedroom dark by using blackout curtains, a sleep mask, and blocking out all light from electronics; and prioritize viewing 2-10 minutes of bright sunlight (outside, not through a window) first thing in the morning.
3. Eat in a way that’s healthy for you. The Whole30’ers I’ve talked to have all reported an increase in HRV just by doing the program. Eating enough calories, macronutrients, and micronutrients to support your unique physiology and activity levels will help you improve HRV. Also, avoid alcohol, because nothing makes your HRV tank faster. Meal timing can also help; avoid big meals within three hours of bedtime.
4. Pay attention to hydration. The more liquid you have in your system, the easier it is for blood to circulate and deliver oxygen and nutrients to your body–so drink up, especially post-exercise. (And consider adding electrolytes like LMNT, because drinking tons of water can flush out electrolytes and defeat the purpose of hydrating.)
Other HRV hacks include cold therapy (cold showers or ice baths), breath work, meditation, listening to music, and journaling–all things that help you reduce stress and keeps your sympathetic nervous system chill.
Evaluating HRV with WHOOP
Your WHOOP 4.0 band tracks your HRV every night, during the last five minutes of your last stage of deep sleep. This is when your body is the most still and your heart rate is the most constant, so it’s easiest to get a highly accurate measurement.
Your HRV is highly variable from day to day; it’s not unusual for me to have a 10 to 20-point drop or improvement in a single day. Completing a detailed Journal when you wake up (like WHOOP prompts you to do) will help you match your behaviors, mood, and current context with your HRV scores, so you can see how yesterday’s therapy session, margarita, late night, or cold shower impacted your nervous system.
Even more important than your day-to-day swings are the trends you’re seeing over time. Use WHOOP’s weekly and monthly performance reports to see if your healthy habits and concerted efforts are helping you increase your average HRV scores as the weeks go on.
Have questions for me about WHOOP or HRV? Find me on Instagram @melissau!