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HRV and Sleep Deprivation: What’s the Connection?

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Measuring your heart rate variability, or HRV, is as easy to do as it is useful. Using just your phone, you can get incredible insights into your physical and mental health, including how your sleep habits affect your life.

What is HRV?

Your heartbeat’s pace varies slightly between beats. Those small intervals between beats are what HRV measures. As you go about your day, our heart adjusts to your body’s experiences, moment by moment, working to keep your body’s systems in balance, no matter what is happening. The time elapsed between two beats will be different when you go for a run, eat a heavy meal, meditate, or react to the news. 

Heart rate variability graph

HRV is closely tied to the workings of your autonomic nervous system, which is made up of two parts — the parasympathetic and the sympathetic.Together, they manage our bodies’ energy expenditures, depending on what we’re experiencing,  and regulate our systems’ activity.

  • The sympathetic system is associated with the fight or flight response and is activated when we’re stressed or working out. Some of the workings of the sympathetic system include sending out hormones like cortisol to keep us alert, increasing our heart rate, and slowing digestion to conserve energy.
  • The parasympathetic system takes care of us when we’re at rest, managing our resting heart rate, helping us relax after a stressful event, and lowering blood pressure.


Both systems affect your heart rate, speeding it up and slowing it down depending on what you’re going through. Though not the only factors at play, the workings of these two systems also affect HRV.

Higher variability is often a sign of a healthy cardiovascular system and that your body is adjusting well to life’s stressors and fluctuations. Low HRV, on the other hand, can often mean something is off. Maybe you’re getting sick, or are too stressed to cope, or are having trouble sleeping. 

HRV measurements were used to monitor the health of astronauts back in the 1960s using an electrocardiogram machine. Nowadays, you can take accurate anytime, with the help of Welltory and your phone’s camera.

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Does Sleep Deprivation Affect HRV?

Given that HRV is an excellent tool for seeing how well you’re doing, it’s no surprise that your heart rate variability is also affected by poor sleep. One study found that sleep deprivation led to lowered HRV, and a decrease in parasympathetic activity, the system responsible for helping you rest and recover. 

How Can HRV Data Help With Sleep Deprivation?

Tracking your HRV can give you a lot of feedback about how you’re doing. The easiest way to see if poor sleep is affecting your health is to take a measurement as soon as you wake up and see how well you recovered during the night by checking your stress and energy levels.

HRV measurements not only let you see how being sleep-deprived affects how you feel, but you’ll also be able to track whether certain behaviors cause disordered sleep. Maybe you’ll notice that your evening cup of tea is actually keeping you up or that working past 7 PM means you’re more likely to toss and turn. 


With Welltory, you can also see how your lifestyle changes influence your HRV and how positive changes to your sleep schedule affect your stress and energy levels the next day. Visualizing those changes can motivate you to find more ways to hack your sleep


If you’re monitoring your sleep using a fitness tracker or a sleep app, Welltory can show you how HRV and sleep deprivation are related but also find meaningful correlations between your measurements and your sleeping patterns, giving you a sleep analysis that shows you how well you slept the night before, along with recommendations to get you sleeping better.  

Welltory sleep analysis

Your sleep score takes into consideration how well you recovered at night, whether you’re sleeping enough and getting to bed at the right time. This personalized assessment can help you see which changes will most impact your sleep quality.

Does Sleep Deprivation Cause an Increased Heart Rate?

In addition to affecting your overall health, not getting enough sleep can also affect your heart rate. Sleep deprivation causes an uptick in your daytime heart rate, in addition to higher blood pressure. Both of these factors put a strain on your heart.  Chronic sleep deprivation, when you’re consistently missing out on the recommended 7-9 hours of sleep, can also affect your heart health in the long term

How Sleep Deprivation Affects Your Stress Levels

Though it won’t affect your health, missing just one night of sleep can increase your stress levels. One study found that after a 24-hour shift, medical students had lower HRV and higher levels of cortisol, the stress hormone. When your body doesn’t get to recover properly, it inevitably affects how well it can cope with internal and external stressors. 

One meta-analysis found that stress consistently led to a decrease in HRV, not surprising given that both higher stress levels and sleep deprivation impact how smoothly your body’s systems are running. 

The kicker is that though sleep deprivation can lead to higher stress levels, stress can also negatively impact sleep quality. If you’re struggling to get enough sleep, take HRV measurements with Welltory to see if consistently high stress levels are a contributing factor.

The Takeaway

Everyone misses a night of sleep once in a while, but regularly tossing and turning can lead to lower HRV and higher stress levels and heart rate. Sleep deprivation, however, is something that you can work on improving. Welltory can help you hone in on which factors are impacting your sleep quality and give you actionable advice that can help alleviate their impact. You’ll also be able to see how small positive changes, like adding breathing exercises to your day, can get you to sleep better and longer.

Welltory Team, 07 Dec. 2022

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