Interpret Your HRV and RHR
Heart rate variability (HRV ) and resting heart rate (RHR ) measured during your sleep both act as a lens into your cardiovascular and autonomic nervous system health, as well as general physical fitness.
Observing changes that occur together in your HRV and RHR is an impactful practice to adopt, given the two have a complementary and essential relationship. In this article, we break down the following:
- What to do about increases and decreases in your HRV and RHR.
- What may be the potential source of these fluctuations.
- Quick tips for improvement, all of which you can experiment with yourself using tags and trends.
Keep in mind: the relationship between HRV and RHR can easily be observed together using Oura on the Web, which allows you to compare two metrics at once.
Why Pay Attention to HRV and RHR?
As humans, we have a finite number of resources and our entire body is constantly competing to use these resources for various vital functions (e.g. digestion, circulation of blood and oxygen to organs, etc). If your resting heart rate is low and heart rate variability is high relative to your baseline, this means your body is not overexerting itself to maintain your systemic functions and therefore, many of your resources (i.e. energy, strength, mental and cognitive capacity, et.c) are available to be reallocated. This is why low RHR and high HRV are core indicators of recovery and relaxation in the body. In other words, you have fuel that’s ready to be used wherever, and whenever necessary.
If your RHR is high and HRV is low, this means many of your resources have already been tapped into and are currently tied up, so there’s less available for your body to pull from. This why having low heart rate variability is a sign you need more time to rest, recover, and recharge. In other words, your body is telling you it's running on reserves and you need to place heavier emphasis on properly refueling, as needed. It’s important to note that although resting heart rate and heart rate variability are physiological indicators, they’re still impacted by and connected to your mental and emotional self—meaning, the “refuel” you may need after recognizing poor trends in your RHR and HRV can be physically, mentally and, or emotionally grounded. At the bottom of this article, we jump into some methods for improvement you can experiment with yourself.
1. What to Do About
Decreases in Your HRV, Increases in Your RHR
If you notice (1) elevations in your resting heart rate that surpass 3-5 BPM (beats per minute) above your normal range and, or (2) declines in your average heart rate variability, this is typically a sign that something is challenging or stressing out your system. You can think of this as a cue from your body, asking you to place greater emphasis on rest, recovery, and finding your ideal balance.
Detecting one, or both of these patterns conjointly could be the result of:
- Your body working to overcome illness
- Short, or inconsistent sleep
- Overtraining, or strenuously training too close to your bedtime (within 3 hours)
- Mental distress, or a currently living a busy and hectic lifestyle
- Poor, or late-night diet selections (i.e. high in sugar, saturated fat, or spicy)
- Heavy evening alcohol consumption
- An overly hot bedroom
All of these factors play a role in putting your body into “overdrive,” which is reflected in your heart. Please note, these are not all of the potential sources of increases in RHR and, or decreases in HRV.
Bonus: If you draw your attention to the bar chart at the top of the screen below, you'll see that higher resting heart rates (indicated by the white circles) tend to be associated with lower Readiness Scores (indicated by the blue bars).
2. What to Do About
Increases in Your HRV, Decreases in Your RHR
If you observe (1) a slight decline in your resting heart rate that is 0-10 BPM below your average and, or (2) a rise from your normal heart rate variability range, this tends to be a sign of peak recovery and preparation to perform at your physical, mental and emotional best.
This is a message from your body that you’re ready to take on a challenge and push yourself outside your normal comfort zone. On the days you observe these patterns, you can think of it as your body telling you to “go for it”. This is the time to take on a difficult workout, try something new for the first time, engage in a creative project, or otherwise go live your best life.
However, please note that significantly higher HRV levels from your normal average are not always a good thing. This can be indicative of low autonomic nervous system stimulation, which may feel like low energy and lethargy. This relates to the idea of hormesis—there is a favorable amount of stress the body needs to thrive. This is why people spend time lifting weights and breaking down muscle fibers to improve their overall strength. Overly high HRV measures are a sign from your body that you’re ready to make your next move in building up your cardiovascular fitness in pursuit of long-term, functional health.
Bonus: If you draw your attention to the bar chart at the top of the screen below, you'll see that lower resting heart rates (indicated by the white circles) tend to be associated with higher Readiness Scores (indicated by the blue bars).
3. A Unique Scenario
Decreases in Your HRV, Decreases in Your RHR
If you recognize your resting heart rate and heart rate variability trending downward together (i.e. they are both falling beneath their normal averages), this is a unique scenario. This is likely a sign you’re in a hyper-recovered state and your body is physically peaking. This is often seen in trained endurance athletes when they’re tapering in the coming days prior to a competitive event, if done properly. If this context is unfamiliar to you, tapering is when athletes gradually reduce their exercise load in the days prior to an important event, such as a race or game.
This relationship occurs because the parasympathetic nervous system (rest-and-digest) will begin to dominate the opposite branch of the autonomic nervous system (sympathetic: fight-or-flight) as someone takes themselves out of a state where physical exertion, high intensity, and excess 'stress' have become the body's norm.
Unless you have been or are interested in intentionally training, keeping an eye out for this trend in your data may not apply to you personally—although if you spot it, we encourage you to seize the moment and take on your version of a challenge, whatever that may be.
How Can I Improve My HRV and RHR ?
Below, you'll find a short selection of behavioral changes that have improved heart rate variability, and balanced resting heart for others at large. We recommend you test a few out for yourself using tags to document your new intervention(s), then monitor any changes to follow in trends. Using tags and trends in combination will help you identify if these mini personal experiments are truly serving your recovery in a positive manner, or not.
- Exercise and train with the right moderations in place. Coming from Oura’s perspective on a balanced lifestyle, this means 2-3 days of moderate to vigorous training per week, with 2-3 days of active rest interlaced between those days. By training, we mean getting your heart and breathing rates up to levels that are outside of your comfort zone. By active rest, we mean taking it slow, but not remaining still or in a seated position all day long.
- Hydrate and cut back on alcohol consumption. Hydration determines blood volume and the more water that you have in your system, the less hard your heart has to beat to circulate the oxygen and nutrients it needs to support the rest of your body. Alcohol not only naturally dehydrates you, but when consumed up to 6 hours before bed, it can keep your heart rate elevated throughout the night, potentially preventing you from entering the restorative stages of sleep (deep and REM). This can significantly impair your recovery and therefore, your HRV.
- Sleep for 7-9 hours per night and keep your sleep and wake times consistent. Sleep consistency is the quickest route to helping you achieve more deep and REM sleep, which holds a direct relationship to boosting HRV.
- Expose yourself to natural light and cold temperatures for short periods of time (e.g. a cold shower, ice bath, or walk outside in cooler temperatures). Getting natural light, especially in the morning immediately upon waking can aid in circadian rhythm alignment. Sleeping according to your internal clock can increase sleep quality, thereby boosting your recovery. Cold exposure can help stimulate your vagus nerve, the longest nerve of your autonomic nervous system, which interfaces with parasympathetic (rest-and-digest) control of your heart, lungs, and digestive system. A simple 45 seconds of cold water at the end of your shower routine, or a quick walk outside in an environment that causes a slight shiver, or goosebumps to form is a great way to gradually ease into things. As your tolerance to the cold builds with repeated practice, you can begin to add time to your interventions, or test out full immersion into brisk water.
- Mindfulness meditation and intentional breathing practices. Adopting slower and controlled breathing rates through meditation and, or intentional breathing practices are known to enhance positive influence of the vagus nerve on your heart. By increasing vagal nerve activity, the parasympathetic (rest-and-digest) nervous system is brought into dominance, which naturally promotes restoration in the body. Test out Oura's Moment or Sleep Sounds feature to put these into immediate practice.
To learn more about RHR and HRV, visit The Pulse.