Heart rate variability (HRV) allows us to optimize training, fasting, and other good stresses by understanding when our body can best handle it. We won’t get over-stressed, which will keep our hormones optimized and keep us feeling great.
Do you sometimes feel like cycle syncing doesn’t work for you? Do you find that your energy levels don’t match what cycle syncing tells you to expect?
We can keep track of HRV during each phase of our cycle to measure our stress and understand our energy fluctuations. Everyone is different, so it’s a great way to personalize cycle syncing.
Once we keep track of HRV through our cycle, we’ll understand which phases we’re most naturally stressed and when we’re best able to add healthy stressors like exercise and fasting. We’ll talk about:
- What is HRV
- How to measure it
- What to do once you know your HRV
- How to increase HRV
- How to track HRV across your cycle to know your best and worst phases
What is HRV?
Heart rate variability, or HRV, measures the difference between each heartbeat. I discovered it naturally in junior high when I noticed my heart rate speeds up as I breathe in and slows down as I breathe out. Our exhale calms our system and slows down our heart rate, which relaxes us. Doubling our exhale count (i.e., breathe in for two and breathe out for four) relaxes our bodies because it helps lower our heart rate.
HRV measures how well our autonomic nervous system (ANS) works. When HRV is higher, our body is better able to calm itself down naturally. On days when HRV is low, it’s common to feel stress and overwhelm more easily.
How to Measure HRV
Most fitness trackers measure heart rate variability. The Oura ring and the FitBit will measure HRV. With the Oura ring, we can see our measured HRV each night and trend it over time.
The Fitbit measures HRV but only displays it when you upgrade to Premium. It’s an option if you want to collect some more data about your health.
If you have a FitBit and don’t want to pay for Premium, or if you don’t have a fitness tracker, some apps use the phone camera to measure HRV. I use HRV4 Training on my Android, and it works well. I like this app because it also asks about how I’m feeling and will give suggestions about how hard to work out. The app tells you if you’re ready for a higher intensity workout or if a less stressful exercise like pilates or yoga might be better.
How to Use HRV
If you’re on this site, you’re likely familiar with the cycle syncing method and how to work out according to your current phase. I have a list of workouts I do during each phase, and I usually have an idea about what I plan to do the day before. When I wake up, if my HRV remains at my average level, I’ll proceed as planned. If it’s lower, I’ll either give myself a rest day, take a walk, do pilates or yoga, or stretch. The next day I’m usually able to do more.
Using HRV to Plan Workouts
When we listen to our bodies and consider HRV, it benefits our performance. Consider two different scenarios. With both, we have a higher intensity workout planned, but our HRV is low, and our body is stressed.
- If you move forward as planned, notice how you feel. Can you work out as hard as usual? Are you able to run as fast or as long as you usually do? Likely, the answer is no. However, you’ve stressed your body more and won’t be ready to work out hard tomorrow either.
- If you take an easy day and allow your body to recover and reschedule the higher intensity day for tomorrow, you’re more likely to be able to work out with full intensity. You get more benefits from your workout.
When we keep pushing because “my workout plan says to,” we’re at risk for injury, illness, or burnout. Our body is telling us it needs a break, and our body will not be able to counteract all of the stress we put on it.
Overdoing it can also cause hormonal imbalances. Doing the higher intensity workout if we’re not ready for it will increase our cortisol (the stress hormone), which will reduce the amount of progesterone we produce, changing our hormonal balance. We’re also likely to feel tired for the rest of the day.
Things That Increase HRV
The cool thing about HRV is our average level will continually increase as we get more fit. Our body gets used to the stress, and we’re better able to relax our body after any stress, not just exercise. We will be able to work out harder, and we’ll feel better because our calming nervous system will better counteract daily stressors.
We need to increase our heart rate variability slowly. To go from couch potato to marathon runner too quickly won’t allow our body to adjust. Instead of improving HRV, it would likely go down, causing stress and illness.
Other things that increase HRV are:
- Good nutrition – Having a good balance of nutrients will help keep stress levels lower.
- Consistent sleep and good sleep hygiene – While we sleep, we’re detoxifying the body. Sleeping well keeps us healthier and will increase our HRV.
- Meditation – Being mindful or spending time meditating helps keep our vagus nerve healthy. And the vagus nerve is one of the primary players in our ANS.
- Being outside, especially at sunrise and sunset – When we’re outside for sunrise and sunset, our eyes see the change in the light, which optimizes sleep hormones. When we watch the sunrise in the morning, we will sleep better that night. The resulting hormone changes can improve HRV.
Things That Decrease HRV
Low HRV is associated with heart disease and death, according to a study in the journal ‘Circulation.’ We should try to avoid things that may be lowering our HRV.
- Alcohol – Even a small amount of alcohol before bed can increase heart rate and decrease HRV as our body works to eliminate the alcohol.
- Stress – Since heart rate variability measures stress, any extra stress will lower HRV. Any stressors in your life can decrease HRV, including relationship stress, work stress, and health concerns.
- Too much exercise – When we jump into an exercise program and go from couch potato to working out daily, we will decrease our HRV levels. Our body doesn’t have time to recover, and it can do more harm than good. If we pay attention to our HRV as we increase our workouts, we can give ourselves the rest we need when we need it, and over time our HRV will increase instead of decrease.
HRV Through Our Cycle
Some studies have shown HRV will fluctuate throughout our cycle. Our body can handle stress and calm our system better in the follicular and ovulation phases than it can in the luteal and menstrual phases. These proven differences are why cycle syncing suggests working out harder and taking fewer rest days during the follicular and ovulation phases.
During the luteal phase (especially the second half) and menstruation, our HRV will tend to be lower. When we work out harder, we’re more likely to need a rest day the next day or two.
I’ve enjoyed paying attention to this, and it has shown me my body has more ability to push during the follicular phase. And while cycle syncing suggests doing the highest intensity workouts during the ovulation phase, this doesn’t work for my body. I’ve found my HRV lowers during ovulation and then comes back up a day later. We’re all different, and it helps to know exactly how we respond. Then we can take a rest when our body needs it and work out harder when we can handle the stress.
For the Skimmers – A Quick Summary
Measuring our HRV is an easy way to understand how much stress our bodies can handle. We can use it to decide whether it’s a good idea to relax or work hard each day. We can use a fitness tracker or app to measure HRV each day and pay attention to trends.
HRV helps us realize what improves our health – sleep, good nutrition, and meditation. And also what affects us negatively, like alcohol, stress, and too much exercise. As we keep track, we can see which cycle phases stress our body more. Everyone’s stress levels fluctuate differently, so we can’t all follow traditional cycle syncing advice.
When we look at data, we can personalize our approach, making cycle syncing easier and more appropriate for us. Sign up for the mini-course to learn what to measure to customize cycle syncing. We can improve our health and energy while working out less.