Your wearable gave you a number this morning. Before you let it decide how you feel about your day, here's what it may and may not be telling you.
There's a moment many of us have had with a wearable. You check your score before you've even had coffee, and there it is: lower than yesterday.
You slept fine, you think. You didn't drink. Nothing feels particularly different. And yet the number is sitting on your wrist like a small disappointment before the day has even begun.
If you've ever wondered what HRV is and whether you should actually care about your score, you're not alone.
Heart rate variability, or HRV, is the tiny variation in time between one heartbeat and the next. It gives us some insight into how your nervous system is responding and adapting to the demands placed on it.
But here's the important part: HRV is intensely individual.
Your age, genetics, fitness, sleep, stress, hormones and stage of life can all influence your number. So before you decide that a lower score means you're doing something wrong, take a breath.
The short answer
Yes, HRV can be useful. But the number matters far less on its own than the pattern over time and the context of your actual life.
The point is not to wake up every morning with another score to improve.
It's to understand your body a little better.
So, what exactly is HRV?
Despite what the name suggests, heart rate variability isn't about how fast your heart is beating.
It refers to the small differences in time between one heartbeat and the next.
Your heart doesn't beat like a perfectly steady metronome. The space between beats is constantly changing, responding to signals from your nervous system.
Generally speaking, higher HRV is associated with greater flexibility in the autonomic nervous system the system that helps your body respond to stress, rest and the changing demands of everyday life. Lower HRV has also been associated in research with certain health risks.
But this is where HRV can become confusing.
A higher score is not a universal gold star, and a lower score isn't automatically bad news.
There is no single “perfect” HRV number that every woman should be aiming for.
Your own trend, in context, is usually more useful than comparing yourself with anyone else.
Why did my HRV suddenly drop?
This is probably the question most people ask after looking at their wearable.
The answer can be frustratingly simple: a lot of things can affect HRV.
Sleep, alcohol, exercise, stress and illness can all influence it. But for women, there is another important piece of the picture that isn't always reflected clearly in the data on your app: our bodies can change considerably from month to month and throughout our lives.
Your menstrual cycle, pregnancy, postpartum recovery and the hormonal changes around perimenopause and menopause can all influence the body and its autonomic nervous system.
This means that the same HRV number may mean something different depending on where you are in the month and in your life.
A lower number after a difficult week at work might tell a different story from a lower number before your period. A low score during pregnancy is not necessarily the same thing as a low score when you're otherwise healthy and well rested.
This is why context matters.
The number alone cannot tell the whole story.
Should I compare my HRV with other people's?
In short: probably not.
One person's normal HRV can look very different from another's. Genetics, age, fitness and the device you are using can all influence the number you see.
Comparing your HRV with your friend's or with a stranger online telling you theirs is 90 is unlikely to tell you much about your own health.
Instead, it can be more useful to look at your personal pattern.
What does your HRV generally look like when you're feeling well rested?
What happens after several poor nights of sleep?
Does it change after alcohol? During particularly stressful periods? After a busy week when you've been trying to do absolutely everything?
Over time, the pattern may become more interesting than any individual morning.
And for women who track their cycle, comparing similar points in different months may sometimes make more sense than comparing Monday with Tuesday.
Can you improve your HRV?
This is where the internet can make things unnecessarily complicated.
You could, theoretically, build yourself an entire HRV optimisation programme. Slow breathing. Cold exposure. Intervals. Supplements. Meditation. Better sleep. More exercise. Less exercise. No alcohol.
And suddenly, the nervous system you were trying to support has another full-time job.
The good news is that some of the things associated with supporting HRV are not particularly glamorous.
Sleep. Movement. Recovery. Breathing. Not attempting everything at once.
Research suggests that practices such as slow-paced breathing can produce measurable changes in HRV. Regular exercise can also support cardiovascular and autonomic health. And alcohol, particularly close to bedtime, can affect overnight heart rate, HRV and sleep.
But Nite-Nite's view is that you don't need to turn this information into another performance.
If a fifteen-minute breathing practice helps you feel calmer before bed, lovely. If going for a walk helps you clear your head after a long day, that's useful too.
The goal isn't to become a woman with the world's most impressive readiness score.
It's to create enough space in your life for your body to recover.
When tracking stops being helpful
There is also a version of HRV tracking that quietly goes wrong.
The morning reading starts to set the emotional weather for the day.
A low score makes you anxious. A high score makes you feel virtuous. You begin checking before you've checked in with yourself.
And suddenly, the technology designed to give you information is telling you how you should feel.
If that sounds familiar, it may be worth remembering that your wearable is measuring one part of your physiology not the whole of you.
You can have a low HRV score and still have a good day.
You can have a high score and still need rest.
And if tracking your sleep, recovery or HRV is making you more anxious rather than more informed, the tracking may have stopped serving you.
That's information too.
One last thing
Some weeks are heavy.
Some months are heavier. Some years ask more of us than others.
A body that reflects that isn't necessarily failing. It may simply be responding.
HRV can be a useful piece of information, particularly when you look at your own trends over time and alongside how you actually feel. But it doesn't need to become another number to optimise, improve or worry about.
Because the point was never the number.
It was the capacity underneath it.
And sometimes, the kindest thing you can do for that capacity isn't another protocol.
It might simply be an earlier night.
A few things for your wind-down
If you want to create a calmer evening around rest rather than recovery scores, you might explore:
- A journal for getting tomorrow's thoughts out of your head.
- A calming ritual or breathing tool for creating a little pause between the day and bedtime.
- Something from your bedside library because sometimes reading a few pages is more useful than checking one more number.
Explore Nite-Nite's Evening Rituals, Sleep Tech and Bedside Library.
Resources
The research and further reading used in the original article include:
- Research on HRV and cardiovascular health
- Schmalenberger et al., Journal of Clinical Medicine (2020) — menstrual cycle changes in vagally mediated HRV
- Research on HRV during pregnancy and postpartum
- Slow-paced breathing meta-analysis (2024)
- Research on exercise and heart rate variability
- Brown et al., Psychosomatic Medicine (2021) — mindfulness and meditation and vagally mediated HRV
- Research on the real-world effects of alcohol on heart rate, sleep and HRV
Nite-Nite note: HRV is a personal metric and cannot diagnose a health condition. If you have concerns about your heart health or a significant change in how you feel, speak with a qualified healthcare professional.
