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The Importance of Monitoring Your Heart Rate for a Fitter & Healthier You

Updated: Dec 14, 2023

You've been training for a few years, but don't seem to progress any further. You run the same route and just can't shake the time. The most common reason you are not progressing at all is your intensity. You are training too hard most of the time. Here's how to make a shift and start kicking ass.


Understanding a few crucial facts about your heart rate and heart function provides insight into the internal dynamics of your body. When talking about the monitoring of your heart rate during exercise, the focus is on comprehending your internal effort. Heart function can be gauged by the frequency of each beat, commonly referred to as Heart Rate (HR), or the volume of blood the heart pumps with each contraction (stroke volume).


You as a runner can easily monitor your HR with a reliable smart watch with chest strap, like Garmin or Suunto watch. Stroke volume is more difficult to measure, typically done with a Dopple ultrasound or with ECG. Given the complexity of measuring the latter, we will set it aside.


Monitoring internal load, such as heart rate, has become relatively straightforward in contemporary times with the availability of heart rate monitors.



In the world of running, external load can be quantified through metrics like pace or power, as observed in cycling. While running power measurement is not as straightforward, some companies offer power meters. The specific parameters they measure remain somewhat unclear. I've personally used Stryd power meter, but learned that 1. too many metrics can be confusing 2. too many metrics take away the freedom and joy from my running.


My personal take is also not to let the metric and the next shiny object distract you from the most important thing - and for my training it is consistency. Let's just get the most important thing done, which is to get out the door!


It's essential not to succumb to the allure of yet another marketing gimmick solely for the sake of novelty. Wearables capable of measuring heart rate started emerging in the 1990s, they were god-ugly and clunky! Despite the prevalence of these devices, many individuals remain uncertain about how to leverage them effectively to improve their fitness. And Health.


So what does health got to do with this at all?


Health has everything to do with performance. Human body is resilient, and we can push through some really hard stuff, but eventually, if you've been ignoring your health for a while - your body WILL find a way to sit your sorry ass on a couch.


Your central nervous system regulates your heart rate, whether you want it or not. When you're stress #af, your CNS is on overdrive, and so is your heart. So let's dive into how you can interpret what is going on with you with a simple tool of HR and HRV.


This article aims to guide you through the effective use of heart rate-measuring wearables.



Optimizing your training using heart rate is pretty straightforward once you understand some basics


We all know exercise is good for your heart health. Your heart grows larger and more efficient as you get fitter - or is it because your heart gets fitter?! Athletes often boast larger hearts, enabling them to pump out a greater volume of blood compared to your average Jane/Joe. In contrast, heart rate is a highly individual metric, somewhat age-dependent, and tends to decrease with aging. A top-tier runner might exhibit a maximum heart rate anywhere between 160 and 210, with both ranges considered healthy and efficient.


Contrary to popular belief, our primary interest lies not in maximal heart rate but in two submaximal intensities crucial to our performance. The first is the Aerobic Threshold, or Ventilatory Threshold 1, situated around 65-70% of your Heart Rate Reserve (for those interested, the Karvonen Method is worth exploring) or Maximal Aerobic Function (MAF, detailed by Dr. Phil Maffetone, can be explored further here: https://philmaffetone.com/method/).


This blog post zeroes in on this threshold, often overlooked by most recreational athletes or those initiating a regular exercise routine. It's not to diminish the importance of training around the second ventilatory or "lactate" threshold, but to emphasize that low heart rate training is an underappreciated intensity, overlooked by beginners and even seasoned veterans.


The second threshold, the Anaerobic or Lactate Threshold, typically hovers around 87-92% of your max heart rate. For very top athletes this threshold will inch even closer to 95% of max hr. It marks the point at which exercise intensity is high, and sustaining it becomes viable for only about 45-60 minutes, think your 10K running efforts. Many gravitate towards this intensity due to the perception that exerting at this level ensures substantial gains, aligning with the popular "No Pain, No Gain" mindset. By the way, you may want to listen to this episode of The Athlete's Compass podcast to find out why this philosophy is at fault.


Ok, but what about resting heart rate. It is here you will find lies the difference between a fit individual and less fit. Because of the enhanced size and efficiency of Athlete's Heart, their resting heart rate is typically low. In clinical terms, "abnormally" low, under 60 beats. For an endurance athlete, resting heart rate can be even under 30. Mine typically sit between 45 to 51.


In addition to your resting heart, you can now access your beat-to-beat variation, that is a good mesure of your central nervous system drive. If you have a large variability, your body is most likely in the "rest & digest" mode, you are healthy, you are coping well with your training and recovering optimally. When the beats become more alike one another, more steady with less variability, your Heart Rate Variability is low. This is when your body is sending you signals that CNS is switching over to "Flight or Fight" mode, which is a sign that you are not recovering from the stress, whether it is training load, life style stress or emotional stress.


There are several methods to measure your HRV, like Oura ring, or just with your phone with an app HRV4Training.


Using HRV to guide your training can be very helpful as you learn to trust your body's signals. Always keep in mind to use a 3-4 days rolling average when making decisions in your training plan, especially linked with your overall feel. Don't feel too hot and HRV is on a downward trend, switch to something that stimulates your parasympathetic mode, rest & digest, like walking in the nature, easy swim or yoga.


This blog post intentionally sidesteps the discussion of the Anaerobic Threshold because I firmly believe that the first threshold is far more pivotal, yet often neglected for continuous improvement in performance among most recreational athletes. I will save VT2 for another blog post.


So why shoul I train at easy, low intensity?


Why is exercising at low intensity so crucial? Won't I become sluggish if I train slowly?


Paying attention to your heart rate as a gauge of training intensity is important for several reasons. Scientific studies have consistently demonstrated that an 80% focus on low-intensity and 20% on high-intensity training yields reliable improvements in performance.


The exact distribution depends on factors such as the athlete's training status, available weekly training time (with greater time allowing for a potentially more significant emphasis on the 80/20 ratio), and the specific performance goal.


The distribution can also vary based on the phase of your training year. As you approach a key race, emphasizing race pace efforts becomes more crucial.


The central message is that the majority of your training should be at low intensity. However, many recreational athletes often find themselves stuck in a cycle of too much moderate or high-intensity training, leaving them fighting low-grade systematic inflammation (as often is experienced as frequent colds, headaches, injuries that never seem to go away), and in worse case, injuries, illnesses and overtraining.


Engaging in excessive moderate or high-intensity training can hinder recovery for subsequent workouts. It also poses challenges in increasing training volume, a crucial element in progressive overload and fitness improvement (up to a certain extent).


Moreover, excessive intensity raises the risk of injuries and overtraining. The need for extended recovery clashes with the realities of our lives—poor sleep, high-stress workloads, and suboptimal nutritional choices. Our bodies and minds struggle to recover.


You'll start to skip the next workout.

And another.

And then you try to catch up, because you didn't do what was in your plan.


Constantly pushing yourself to the limit is taxing on your nervous system and adds to the stress in our already demanding lives. The result? Training feels exhausting and mundane. Your motivation start to dwindle. The repetition of the same sessions becomes akin to chewing on sweaty old socks. Despite your efforts, improvements seem elusive.


Convinced yet?




Low-intensity training ABCs


Firstly, securing a reliable and accurate heart rate monitor is paramount. It's crucial to note that most optical heart rate monitors, especially those measuring from the wrist, are not sufficiently accurate. Opt for a chest strap for a higher quality of measurement. And make sure to change the battery on those badboys every few months depending on your usage.


Garbage in, Garbage out!



Secondly, employ Maffetone's 180 formula: subtract your age from 180. For instance, if you're 44, the calculation is 180 - 44 = 136. Depending on your lifestyle, training status, and health, consider adjusting by 5-10. This will give you your Target Low-Intensity Heart Rate. For details how to adjust your target heart rate, see Maffetone Method. If you are new to regular training, substrack 10 (so your target MAF would then be 126. If you have been training well for two or more yeas, add 5-10. See the difference? Less fit athletes are going to be walking or doing walk-run method. And that's completely ok. This is where you are right now.


It is useful to test and retest your MAF intensity target every few months. Here's an example of my MAF test.


Proceed to embark on your run at approximately this heart rate, allowing for a variance of ±5 beats per minute. Many watches enable you to program an alert if you exceed this threshold. See the video for more details.


Note that this applies to other modes of endurance, like biking. But remember that because you are using less muscle mass to pedal (your upper body is nearly motionless) than running, or Cross-Country skiing, your heart rate will be 5-10 beats lower in biking than in running.


Now, arm yourself with patience and commitment because your initial runs will be notably slow. You might find yourself walking more frequently.


Be aware of the temptation to call this approach BS and move back to the zone 3 glory.







Yet, if you persevere with consistency and commitment, you'll witness a drop in your pace while maintaining your heart rate within the target range. At that point, you'll be thrilled you stuck with it, perhaps even sending me a thank-you email—no pressure, just a friendly hint! 😄


Here's the ugly truth: if you are burning the candle at both ends, you will find out quickly by doing this test, that your aerobic base is garbage.


I've seen this many times in my coaching business, and with myself. The pace where the MAF target lies is slow. Athletes need to walk to keep it around the target. It IS frustrating. I get that.


But it is a sign that your lifestyle including nutrition, sleep, overall stress (emotional, physical, environmental) is out of whack and no matter how much you train at high intensity, your performance is not improving.


But the good news is that once you take a grip on all those factors, you can see rapid improvements! And I am talking weeks to few months.


Call me.




Top 3 tips on how to adhere to low heart rate training


So you've decided to give this a go? Great! How do you start?


  1. Begin with the walk-run method, starting with a 1-minute run followed by a 1-minute walk. Gradually increase the run duration in each workout. If you're quite fit, consider starting with a 10-minute run or running until your heart rate reaches the Target HR, followed by a 1-minute walk break. Alternatively, run around your MAF target HR and adjust your pace as fatigue sets in and your HR rises.

  2. Opt for flat or rolling hills during your run and walk uphill.

  3. Choose a running partner who maintains a slower pace than you.

Be mindful that improvements may take months to manifest. Personally, I reduced my pace by 1 min/km at 136 bpm in four months of consistently running around my MAF target of 130-137 bpm. My MAF running pace improved from late November to early April, consistently aligning with my MAF heart rate of 136 bpm.


The pace at which your heart rate aligns with the target will increase if you remain dedicated. Once you observe this shift, you'll be astounded at how effortlessly you can run much faster. And this IS the secret sauce for an endurance athlete. Run/bike/ski faster with less effort.


What about the other 20%?


When you stick to low-intensity training like bees on honey for the majority of your workout routine, you'll not only feel better and fitter but also witness improvements in your performance.



Low-intensity training induces several physiological changes, including an increase in mitochondria in your muscle cells (which function as the power plants of your muscles), increased capillary density (helping the transport of more oxygen-carrying blood to your muscle cells), and improved fat oxidation (your body's preference for using fat, an energy source with nearly unlimited stores) during low-intensity efforts.


Opting for a slower pace enables quicker recovery, enabling you to tackle intense sessions with greater oomph. This, naturally, translates into improved overall performance.


Now, does heart rate matter during those demanding sessions? Well, it's a bit more nuanced. Given the inherent delay in your heart rate reaching its maximum frequency, we don't place significant emphasis on monitoring heart rate during hard sessions.


In interval sessions lasting from 30 seconds to 4 minutes, for instance, the focus is on gauging effort through Perceived Rate of Exertion (on a scale of 0-10, where 0 is rest and 10 is maximum sprinting). It's crucial to maintain an effort level around 8-10, as outlined in the chart below.




However, when it comes to tempo runs or threshold runs lasting 10 minutes or more, monitoring both heart rate and effort becomes crucial. As these runs typically fall within Zone 3 (moderate intensity), it's essential to ensure you're not pushing too hard. The recommended RPE for this intensity is around 5-6, while for threshold efforts, we're looking at an RPE of 7-8. At this intensity, it's important to note that maximum effort should not extend beyond 45-60 minutes before reaching a point of exhaustion—typically equivalent to a 10K effort for most individuals.



...But My Heart Rate Seems to be Off Today


Understanding that daily heart rate can fluctuate based on factors such as hydration, nutrition, and overall stress levels provides valuable insights, making day-to-day adjustments more manageable and preventing unnecessary frustration.


I'm looking at you moms. You know your heart rate sky rockets when dealing with naughty kids and/or trying to get your troops out the door. Am I right?! After a sleepless night, your heart is a little less happy, and beating with more regular rhythm... remember, less variability, lower HRV.


When embarking on a low-intensity run and your heart rate appears higher than usual, rely on your instincts. Easy runs should ideally align with a Rate of Perceived Exertion (RPE) of 1-3, not exceeding 4. This translates to a conversational pace where maintaining a dialogue is comfortable. You should also be able to breath through your nose. I know what you are going to say: Impossible! It's a matter of being willing and open to learn.


It's not just about words but forming coherent sentences, and this is where having a running partner slightly slower than you proves beneficial. A conversational pace becomes more attainable, enhancing the overall experience.






I'll tell you that my best ideas always happen during Zone 2 runs...


Now, the concern often arises: am I going too slow with a slower partner? This is a common question, with individuals fearing they might not be exerting enough effort. If you ALWAYS hit your runs at zone1-2, you may be leaving something on table come race day. It's crucial to incorporate a mix of intensities, experimenting with the 80/20 rule and see what works for you.


However, running with a slower friend once a week can be a highly effective strategy. It can be more challenging to maintain a slow pace than hitting a moderate intensity. Therefore, having a slower running partner, even if it's just once a week, ensures that you're truly going at the intended low intensity. The benefits of this approach are substantial, making it a practice worth encouraging.


How Do I Really Know I am Fitter?


An easy way to assess this is to do a MAF test as prescribed in the video above. Doing this regularly as you learn your low-intensity target is a great way to keep yourself motivated, and tracking your progress. I would personally not do this test every month, but every other month at most. Always do the test at the same time, in the same place if possible. Avoid hills!


There are of course other methods to monitor your progress, which I will delve into on another blog.


Take home message


In summary, incorporating heart rate monitoring into your training program serves as a crucial tool to improve your health, performance as well as to prevent overtraining and burnout. The specific percentage of training at low intensity, whether it's 80%, 90%, or 70%, is a decision best made collaboratively with your coach based on your individual needs and goals.


Over time, as you become more attuned to your body, you'll discover the optimal balance for your unique circumstances.


On a personal note, I found that maintaining an intensity distribution of 60% at low intensity and the remaining at moderate or high intensity for three months proved too demanding.

This led to exhaustion and a deep overtraining syndrome with exhausted HPA axis. Personally, I've thrived with an 80%-90% low-intensity distribution, recognizing that this distribution may vary during different phases of my training season.


You can delve into my experience and how I navigated the challenges of overtraining with the support of Athletica and my coach, The Prof Paul Laursen, PhD, in this article: https://athletica.ai/from-overtraining-to-world-championships/


Here are my two reasons why monitoring heart rate is essential for you as an everyday athlete:

1. Training Intensity control (don't burn the candle both ends)

3. Monitor your progress over time (what gets measured, gets improved)


In my training routine, as I embark on new goals, the commencement involves a test week. MAF tests, both on the bike and run, provide valuable data points indicating whether I need to prioritize a slower pace to optimize my aerobic function. I also test the second ventilatory threshold with a 5K time trial in running and Functional Threshold Power in biking.


I hope this blog post has provided you with insights into the importance of heart rate and how you can utilize your smartwatch more effectively as you pursue your next goals. Feel free to drop any questions or comments below.





PS. Follow my journey on IG at www.instagram.com/tiredmomruns

I am also open for more athletes, book your FREE consultation here.

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