Heart Rate Monitoring with the Polar Vantage M3 in Practice

Introduction to Heart Rate Monitoring in Training

Bálint Szinte, national team member of UTE, World Championship participant, and National Champion middle-distance runner. 800m: 1:47.84, 1500m: 3:44.26

Heart Rate Monitoring and Heart Rate Zones in a Middle-Distance Runner’s Training System

Nowadays, most middle-distance runners typically perform their prescribed training sessions based on heart rate and lactate levels to achieve the specific goals of each workout with the most economical effort. After all, if training is performed solely with a focus on time results, there is a risk of illness or injury, and without proper load monitoring, these crises often occur. All of us, competitive athletes, during certain periods, either due to our motivation or overly ambitious expectations, apply a higher-than-ideal load on our bodies, and to counterbalance this, monitoring our heart rate — while not sufficient on its own — can serve a preventive function. From all this, it follows that training load includes both external load, which consists of objectively measurable results, and internal load, which closely relates to training intensity.[1] Heart rate monitoring falls into the latter category, and its monitoring — especially in terms of accuracy — has shown significant progress in recent years. Polar was the first in the world to introduce wireless heart rate monitoring, and since then, they have taken optical heart rate monitoring to a new level, increasing accuracy and enabling energy-efficient, 24/7 monitoring.[2]

This article was made possible with the support of Danubius Track Club and Polar Hungary. Danubius Track Club has provided me with expert backing and the conditions necessary for professional preparation over the years, while Polar’s cutting-edge technology — particularly the Polar Vantage M3 and Verity Sense — enables precise and conscious training monitoring. Today, heart rate control and proper load management are essential for injury-free progress and optimal race preparation, where both partners play a key role.

The Role of Heart Rate Zones in Training Load

The benchmark for heart rate-based training is the personalized heart rate zone that can be tailored to fit the training plan. This scale is related to exertion, somewhat to the lactate threshold, and to the speed–endurance spectrum. While most middle-distance runners generally use the common five-zone spectrum, terminology related to this may differ; for example, some training practices and theories use three-zone divisions. Polar devices use the widely adopted five-zone system. Heart rate zones can be defined in two ways: based on maximum heart rate or heart rate reserve. Since the latter refers to the difference between the maximum and resting heart rate, it is more advisable to use this as the benchmark, as both resting and maximum heart rate are variable data. Moreover, a higher resting heart rate can also indicate overload.[3] Understandably, in a heart rate zone definition based solely on maximum heart rate, only one variable value is used, resulting in potentially less accurate zone definitions. The range and structure of each zone approximately align with physical exertion and the ten-point Relative Physical Effort (RPE) scale — not precisely, because heart rate is not the sole factor determining load; temperature conditions, terrain, or musculoskeletal pain may also play a role[4]. In the five-zone breakdown I use, each zone has a specific effect: while the first zone primarily aids recovery, the following ones initially aim to improve endurance and ultimately to enhance maximum speed.[5]

Practical Use of Heart Rate Zones

In practice, heart rate zones assist middle-distance runners in two key areas. First, they provide feedback on whether the training in a given period was completed with the desired objective, appropriate load, and with improving trends in external load indicators. Nowadays, polarized training plans have become increasingly common, aiming for training with the proper ratio of different load types (e.g., aerobic, anaerobic, functional threshold), specifically emphasizing the greater use of recovery zones.[6] Balanced use is supported if the athlete can continuously monitor the nature of the load relative to the zones. For instance, the Polar Vantage M3 shows weekly data of each zone's ratio through a pie chart, based on personalized heart rate zones. During a preparatory phase focusing on endurance training — aerobic extensive and intensive workouts and functional threshold runs during interval sessions — the dominance of the second and third zones should appear in such evaluations alongside a relatively high amount of recovery runs. Compared to this, as the competition season approaches, the fourth and fifth zones play an increasing role, as these aid the athlete in developing speed endurance and maximum speed.

Internal vs. External Load During Base Training

Secondly, heart rate monitoring is also indispensable for continuous load tracking during training. If we take the training arc again, external load plays barely any significant role during base training — instead, standards related to exertion and heart rate, and possibly lactate levels, define the training. By strictly adhering to these, external load indicators can be analyzed in the training log afterward, and based on this knowledge, the standards can be fine-tuned in the future.

Why I Consider Heart Rate Monitoring Crucial

For me, accurate heart rate monitoring not only provides feedback on the intensity of the workouts but also encourages moderation and more disciplined training. Therefore, I treat heart rate monitoring as a key element in any period of the preparation phase before competitions, which, however, requires an ideal measuring device specifically designed for this purpose. In the following, I would like to demonstrate the practice of heart rate monitoring using the Polar Vantage M3. For more accurate heart rate measurement, I wore the Polar Verity Sense heart rate monitor armband for data recording, which marked a major milestone in optical heart rate monitoring.

Device Setup: The Polar Vantage M3 and Verity Sense

To go back a bit to the “starting point”: How do I prepare heart rate monitoring for training?

I have to start from a simple cliché: even elite athletes have bad days. Our condition is often influenced by external factors, and internal load standards must be optimally adjusted to this. So, on a bad day, I must recognize the intensity with which I should perform a demanding workout, like a 400-meter interval session. Psychologically, it is reassuring to moderate expectations for an upcoming session, knowing my actual state and not putting unnecessary pressure on myself. The Polar Vantage M3 is a modern sports watch that greatly helps in this by allowing me to determine the training load standard for the day on a daily basis.

Using the Orthostatic Test to Monitor Readiness

The Polar Vantage M3 features a so-called orthostatic test, which, especially when done after waking up, provides the resting heart rate. The characteristics, functions, and significance of the orthostatic test would require a more extensive explanation, so I will only refer to it here in relation to heart rate monitoring. It is worth performing this test regularly to track changes in resting heart rate, thus preventing illness or injury risk. Furthermore, 24/7 heart rate monitoring also provides resting heart rate data, but — due to wrist-based measurement — this is less accurate. Therefore, it is advisable to measure resting heart rate in a relaxed state using a chest strap or armband, preferably in the morning right after waking up.

Setting and Adjusting Heart Rate Zones Manually

The Polar Vantage M3 automatically determines heart rate zones, but these values can also be set manually. Based on the regularly reviewed resting heart rate, it is worth reviewing — and if significant changes occur, modifying — the zone thresholds before training. This can be done in the “Sport Profile” menu on the Polar Flow website, which contains the athlete’s profile, allowing for sport-specific manual settings of the zone values. The general benchmark is that the first zone lies between 50–60% of heart rate reserve, and the subsequent zones increase in 10% increments up to the anaerobic zone’s 90% lower limit.[7] Since theories related to training load and internal load differ from each other, and due to individualized training planning, the range of zones may vary from the general.

How I Define My Personalized Heart Rate Zones

In defining the zones, after determining resting heart rate, I calculate heart rate reserve, which is the difference between maximum and resting heart rate. Then I set the percentage thresholds for each zone and, based on previous workout experience, deviate from the standard 10% increment where necessary. A clear example is modifying the upper limit for easy runs, as during endurance base periods, I can jog at a slightly faster average pace compared to a speed-focused period, where such pure endurance workouts are almost entirely removed from the schedule. To be honest, I don’t usually adjust the zones before every workout but do so when I feel the existing zone boundaries are unrealistic based on subjective exertion, thus deeming the modification timely and necessary.

Planning Workouts with Heart Rate Targets

Depending on training periods and types, I calibrate the expected internal load standards for myself. There are two methods for this: the first and simplest is memorizing the heart rate thresholds that should be maintained during the workout. The second method is useful for interval-type sessions, especially when not performed on a marked track. In such cases, I create predefined workouts under the “Add Training Target” menu in the Polar Flow Diary, where I define heart rate zones and their ranges for each workout segment. The main advantage is that the watch immediately notifies me if I exceed any limit, keeping internal load in check.

Regulating Internal Load in Practice

I've often had to scale back during a 20×400-meter interval workout due to a rising trend, yet the overall training result was successful. I've had similar experiences in all vertical hill workouts, where due to varying terrain, the discrepancy between internal and external loads becomes apparent. I used to mess up such hill runs by reaching a high average pace too early, resulting in feeling exhausted by the end. Overall, the regulated and strictly monitored internal load — the primary concept of heart rate monitoring — results in much more consistent training plan adherence and helps prevent illness and injury.

How I Monitor Internal Load During Training

The most important thing is to stay up-to-date with zone thresholds. The simplest way is to memorize the four inter-zone numbers, though Polar also allows displaying heart rate reserve percentages instead of beats per minute on the watch screen. While there’s an option to display a field showing the visual extent of the five zones, I found this takes up too much screen space.

Ultimately, I decide whether heart rate monitoring is necessary — and how I will do it — based on the training type and my internal intuition. The Polar interface allows me to prepare for this easily and with exceptional precision. In my own practice, two key factors determine whether to monitor heart rate and how. As I mentioned before, internal load is not solely influenced by heart rate or lactate levels but also by weather, illness, musculoskeletal pain, or terrain conditions. Thus, my approach to heart rate monitoring is entirely case-dependent.

Two Methods of Monitoring During Workouts

I monitor instantaneous heart rate changes in two ways: either sporadically or using alerts. The deciding factor in choosing the method is the intensity of the workout, as during a threshold or above-threshold interval session, it would be significantly harder for me to keep checking the watch. Similarly, during a more demanding hill run, I might forget to glance at my watch due to the high level of exertion, and I end up ruining the workout. Therefore, in the case of less intense sessions — including warm-ups, during which I previously had a tendency to exceed the ideal exertion levels — I rely on spot checks.

When Heart Rate Becomes Secondary

However, there are also workout types — typically increasingly speed-oriented interval sessions and race-pace-based intervals — for which external load standards are more relevant, and as such, heart rate takes a back seat. In these cases, the end-of-session maximum heart rate and the resting heart rate measured one minute later — or the heart rate between larger blocks or series — become more meaningful. One of the primary goals of such workouts, in terms of internal load, is to reach an anaerobic exertion level.

Why I Use the Verity Sense Armband

During training, I use the Polar Verity Sense monitoring device, which records highly accurate heart rate data at a two-second frequency. The armband monitor, worn on the upper or lower arm, highlights one of its many strengths — comfort — particularly during long-distance sessions and training weeks. Another benefit is its long-lasting battery: when fully charged, I often use it for up to a week.

When Heart Rate Monitoring Also Becomes Valuable in Training Logkeeping: Workout Evaluation Directly on the Sports Watch and in Polar Flow

Workout Evaluation with Polar Devices

Indeed, the Polar Vantage M3 displays basic workout data even after activity recording. For non-interval-type workouts — such as long easy runs or hill runs — I don’t even visit Polar Flow, since the watch itself shows all training data, which I can immediately enter into my personal training log. In the case of interval sessions, Polar Flow provides more detailed insights compared to the watch — it shows the complete data for each lap, and on the heart rate graph, each interval segment is automatically marked.

Analyzing Heart Rate Graphs and Intervals

Especially during interval sessions — but often during hill runs too — I review how heart rate changed over the course of the workout or its intervals, as shown on the five-zone graph along the horizontal axis. This allows me to precisely trace the points where I temporarily exceeded intensity limits by observing the zone boundaries on the graph.

Using Weekly Analysis for Periodization Feedback

The indirect evaluation becomes meaningful more in contexts that go beyond a single training day — for example, in analyzing the training load polarization mentioned earlier, or changes in resting heart rate. This gives me feedback on how well I’ve achieved the objectives of a given period — whether I successfully maintained the appropriate proportion of aerobic-oriented training during a base-building phase. When keeping my training log, I retrospectively evaluate one-week cycles as well as mesocycles, such as base-building or peaking periods[8].

Weekly Load Monitoring and Zone Revision

Previously, I never included the proportions of different load types (e.g., anaerobic or functional threshold) in my training log. With the Polar Vantage M3, I can now review the ratios of these load types on a weekly basis, which allows me to receive feedback during training logkeeping about whether the goal of each seven-day cycle was met. However, this requires periodic revision of the load zones — in other words, updating the resting and maximum heart rate values.

 

References and Further Sources

Chris Napier: A futás tudománya. London, Dorling Kindersley Limited, 2022.

Polar honlapja: Polar Vantage M3 https://tinyurl.com/3wf4urne (Letöltés: 2025. 06. 03.)

Runner’s World honlapja: Polarized Training Is the Fastest Way to Build Endurance Without Burning Out (Letöltés: 2025. 06. 04.)

Virth Balázs előadása az I. Szakmai Napokon