“Listen to your heart”. We hear it in movies and books all the time, yet, while this phrase isn’t commonly used within a fitness context, it is one you can apply to your next workout
How? It all comes down to the time between heartbeats: a measure called heart rate variability (HRV). HRV shifts based on factors like age, fitness level, and daily lifestyle habits. By “listening” to it (in practice, monitoring your heart rate variability) you gain a powerful tool to guide performance, pace yourself, and support post-workout recovery.
Read on to understand what heart rate variability is, why it matters, and how you can use it to manage intensity during your F45 workouts.
HRV meaning: What is heart rate variability?
Heart rate and heart rate variability are two important indicators to consider for your workouts.
Heart rate shows how fast your heart is beating. Monitoring this throughout your workout can help you stay consistent with your session and keep within a chosen heart rate zone. Your heart rate is measured in beats per minute (BPM).
Heart rate variability, or HRV, refers to the minute fluctuations in the time between each heartbeat¹. While it is associated with your heart, HRV is also linked to your brain, and quantifies the load on your nervous system.
The brain controls the activity of several organs through the autonomic nervous system (ANS), including the heart. Your ANS is divided into two main networks of nerves that work in opposition to each other – yet both play a key role in effective training and recovery:
- Sympathetic Nervous System (SNS): responsible for the body’s “fight or flight” response. When the SNS is active, heart rate variability drops as heart rate increases. A lower HRV indicates that stress is high – which can lead to fatigue, and even injury, if ignored.
- Parasympathetic Nervous System (PSNS): is functional during times of rest². When the PSNS is active, heart rate is slower and HRV increases. This is a good benchmark that your body is ready for higher intensity
Depending on the activity being performed, these bodily responses can increase or decrease heart rate variability.
Why HRV matters for training and recovery
Now that you understand what HRV means, the next step is recognizing why it matters.
Tracking your heart rate variability can help you gauge whether your body is ready to train, or if high stress levels are at a peak and you need to schedule a much-needed rest day. In this way, HRV serves as a practical guide for matching the right session to the right day.
That said, paying attention to how your body is feeling is useful – but it won’t give you an accurate picture of your HRV status. A heart rate variability monitor – such as the Reebok Smart Ring– enables you to track patterns, identify your unique HRV range, and establish a reliable baseline.
F45 recommends analyzing your HRV over the course of a week to get a more precise reading – allowing you to progress faster without wasting effort.
HRV and F45 sessions: Applying insights in training
Once you’ve pinpointed your weekly average HRV range, you can use it to guide the intensity of your training to start seeing fitness results – fast. Let’s take a closer look at how a heart rate variability training approach can help you balance hard work and recovery.
HRV training readiness and F45 Training cardio days
As mentioned earlier, a higher HRV status usually means that your CNS is well-recovered and ready for a session that pushes you into a higher heart rate zone. F45 cardio workouts – such as Redline – are ideal in this state, as consistent training in the HIIT workout heart rate zone is linked to improved HRV and overall cardiovascular health³.
HRV and F45 Training resistance sessions
On days when your HRV is lower, it’s best to scale back with lower intensity resistance training. Sessions at F45 Training give you the chance to focus on form and technique – enabling you to move your body, without putting too much strain on your system.
HRV and F45 Recovery
If low HRV and fatigue have set in, your body needs a rest day – remember, recovery is just as important as working out for you to achieve your fitness goals. An active recovery session at F45, such as our new Recovery workout series – Reset, can help to manage injury prevention and avoid overtraining.
HRV and heart rate monitoring tools
HRV monitors, like F45’s LionHeart and the Reebok Smart Ring are the perfect pairing, allowing you to accurately collect data on your unique heart rate variability status, in and out of the studio. The LionHeart monitor manages the efficiency of your workouts, while its unique scoring system makes your group fitness classes even more fun and competitive. While the Reebok Smart Ring tracks your performance alongside the LionHeart monitor, and in the other 23 hrs of the day, outside of the studio, providing an always-on approach to your wellness.
What is a normal HRV range?
In general, research suggests that a healthy HRV typically falls between 19 and 75 milliseconds4. That said, a normal HRV range is unique to everyone – and a ‘normal’ HRV status is influenced by factors such as your age, sex, and lifestyle.
HRV by age
A gradual decline in HRV is a natural part of aging. However, lifestyle plays a major role, and inactivity, poor diet, and unmanaged stress can all contribute.
On the other hand, maintaining regular exercise, eating well, and managing stress can help support healthier heart rate variability as you age. With your heart rate variability by age in mind, consider max heart rate (MHR) to set your training zones during workouts. To find out your maximum heart rate ahead of an F45 workout, simply subtract your age from 2205.
How the Reebok Smart Ring Monitors What Matters
“Biometrics” has become a fitness buzzword—but the Reebok Smart Ring turns it into something far more meaningful. Instead of just tracking data, it transforms essential health metrics into clear, actionable insights that support better training, improved recovery, and smarter decision-making.
At the center of the system are the biometrics that matter most:
- Continuous heart rate monitoring gives you a real-time view of your cardiovascular health—whether you’re easing into sleep or pushing through an F45 cardio burn. This constant feedback helps you train more efficiently and understand how your body responds throughout the day.
- Heart Rate Variability (HRV) tracking offers one of the strongest indicators of recovery and readiness. A higher HRV reflects a well-recovered, resilient nervous system that’s primed for peak performance. A lower HRV signals elevated stress or fatigue, suggesting it may be time for an F45 recovery session or even a full rest day.
- SpO₂ (blood oxygen saturation) helps you stay in tune with your body’s oxygen levels—key for identifying early signs of fatigue, understanding respiratory patterns, and anticipating how much recovery your body needs.
Together, these metrics allow the Reebok Smart Ring to go far beyond passive tracking. It becomes a daily guide—giving you the clarity to adjust intensity, manage stress, improve sleep, and optimize every phase of your F45 Training journey. The optimal way to ensure that your HRV is on track and identify the gaps if it’s not.
Top Tip: Get the Best HRV Reading
For anyone looking to get the most accurate HRV insights, timing matters. Heart rate variability naturally fluctuates throughout the day in response to stress, movement, caffeine, training load, and even emotions. That’s why one of the top recommendations from physiologists is to take HRV readings at the same time each day—ideally overnight or first thing in the morning, before your body has had a chance to react to daily stressors 7.
This is where the Reebok Smart Ring has a real advantage. While many wearables collect valuable HRV data, smart rings tend to deliver cleaner, more reliable readings because they shift less during sleep. With minimal movement and consistent skin contact, nighttime HRV tracking becomes significantly more precise—helping users establish a stable baseline and track trends over time. Instead of relying on sporadic snapshots, you get a clear, continuous picture of your recovery, readiness, and overall physiological balance.
For anyone focused on performance, wellness, or simply understanding how their body responds to life’s stresses, leveraging overnight HRV data from the Reebok Smart Ring is an easy win. It turns a passive moment—sleep—into the most accurate window into your autonomic nervous system, and makes daily readiness insights far more meaningful.
How to improve HRV for better performance
Now that you know what HRV is and how to monitor it, explore how you can use HRV to optimize performance below:
- Get quality sleep: This is key to ensure you are recovering and managing higher HRV levels. To help, explore our hacks to improve sleep quality.
- Stay hydrated and eat well: A healthy mix of protein, carbs and fats – plus plenty of water – can help flush stress out your nervous system and improve HRV.
- Manage your stress levels: Let your PSNS take over by doing whatever relaxes you – listening to your favorite song or deep breathing5 have been shown to help.
- Apply your HRV at F45: Use your LionHeart along with your Reebok Smart Ring– and your knowledge of high-workout heart rate zones – to get the most out of your F45 training. Alternate class types to build a sustainable workout routine and prioritize recovery to train hard – and smart!
Heart rate variability training is an effective way to improve your performance and recovery, helping you achieve better results. Now, learn how you can further improve your HRV with our guide to the benefits of aerobic exercise for your health.
Check out the Reebok Smart Ring and learn more on how to take your fitness to the next level.
Sources:
1 – https://www.health.harvard.edu/blog/heart-rate-variability-new-way-track-well-2017112212789
2 – https://my.clevelandclinic.org/health/body/23266-parasympathetic-nervous-system-psns
3 – https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.657274/full
4 – https://www.webmd.com/heart/what-is-heart-rate-variability
5 – https://medlineplus.gov/ency/imagepages/18138.htm
6 – https://www.hss.edu/health-library/move-better/parasympathetic-nervous-system
