Thanks to modern technology, we know more about ourselves than ever before. Our phones track our daily step count. Some rings assess sleep quality, there's CGMs that measure blood sugar, and wearable trackers that track multiple other metrics. Recently, there’s been a fair amount of buzz about heart rate variability (HRV.)
Once used in the context of athletes and biohackers, this metric has now been started to be used by the general population to assess recovery, stress, and longevity.
So what exactly is HRV, and what can you do to improve your score?
To put it simply, HRV measures how much variation there is in the time that passes between each beat of the heart. It’s usually measured in milliseconds.
Interestingly, your heart doesn’t beat in a perfect or regular rhythm. For example, if your heart rate during a walk is 120 beats per minute – it doesn’t always mean that your heart is beating twice every second with evenly spaced time between beats. However, you’re mostly unaware of these tiny fluctuations.
Why is HRV important?
Essentially, HRV measurements help us understand how well our body is recovering from the stressors in our lives.
A high HRV score means more variability between each heartbeat and indicates that your body responds and adapts well to stress and physical activity.
A low HRV score may indicate an imbalance in your autonomic nervous system (ANS) and can be a predictor of disease risk and mortality.
Being chronically stressed is associated with lower HRV. So is being a perfectionist. If your system is persistently in a flight-or-fight mode, the variation between heartbeats is low. On the flip side, if you’re more relaxed – the variation is higher. In general, healthier states are indicated by greater heart rate variability.
Essentially, the healthier the ANS, the more efficient you’re at switching gears – demonstrating more resilience and flexibility.
What is a healthy HRV?
Instead of worrying about what is good or normal, it’s much more practical to follow your own HRV trends. If you’re making efforts to better your overall health and fitness, over time you should see your heart rate variability begin to rise. On the other hand, a downward trend in HRV can be a sign that you’re overtraining or engaging in other unhealthy behaviours, like poor nutrition or insufficient sleep.
Either way, HRV is a sensitive metric that varies drastically throughout the day. Consequently, there’s no need to track it continuously. Even changes in your breathing while asleep can affect it.
How to improve your heart rate variability
- Sleep: By getting at least 7 hours of sleep per night (more if you feel you need it), you can help your body decrease stress and maintain balance.
- Deep breathing: Deep belly breathing through the nose, focusing on longer exhales, can help activate the parasympathetic nervous system (PNS) and send signals to slow the heart rate.
- Hydration: Dehydration is also linked to reduced sleep quality, which indirectly impacts HRV. You can get water from both food and drinks.
- Exercise & Recovery: Zone 2 training can improve HRV over time. In zone training, you exercise within specified heart rate zones. This is commonly measured by a percentage of max heart rate (MHR). Zone 2 falls somewhere in the ~60-75% of MHR range. It’s also equally important to scale back exercise when required and prioritize rest.
- Decrease alcohol consumption: The impact on HRV may be due to indirect effects in that alcohol consumption generally reduces sleep quality and dehydrates the body, both of which are known factors in reducing HRV.