Optimizing training intensity using maximum heart rate percentage, or % HR Max, is a cornerstone of personalized running program design. This methodology, rooted in exercise physiology, allows for tailored workout intensities that align with individual goals and capabilities.
In this detailed exploration, we delve into the scientific underpinnings of % HR Max, present methods for its calculation with a focus on accuracy, and demonstrate how to effectively incorporate these insights into a training regimen.
Additionally, we discuss the significance of precise tracking and the role of scientific evidence in refining these processes.
The science of % HR Max
The relationship between heart rate and exercise intensity is well-documented, with HR Max serving as a critical benchmark for determining workout zones.
Research underscores that heart rate linearly correlates with oxygen uptake until maximal exertion, making % HR Max a reliable indicator of aerobic and anaerobic energy expenditure (1).
Training at specific % HR Max ranges targets distinct physiological adaptations. For instance, zones below 70% HR Max primarily stimulate aerobic metabolism, enhancing endurance, while zones above 85% HR Max increase anaerobic capacity and VO2 max (2).
Using HR Max in practice
Traditional formulas like 220 - age have been criticized for their broad generalization. In response, more accurate equations such as the Tanaka formula (208 - (0.7 x age)) offer improved estimates across different age groups (3). However, individual variance necessitates more personalized assessments.
For example, conducting a field test like the Cooper test, where one runs as far as possible within 12 minutes, can provide a more precise HR Max by observing the highest heart rate achieved.
To illustrate, a 30-year-old runner using the Tanaka formula would calculate their HR Max as 208 - (0.7 x 30) = 187 bpm. If this runner reaches a heart rate of 192 bpm during a Cooper test, the latter value should be used for more accurate training zone calculations.
Personalized field tests: the Cooper test
For those seeking precision beyond estimations, the Cooper test emerges as a valuable tool. This field test involves running as far as possible within 12 minutes, a challenge designed to push the cardiovascular system to its limit.
The highest heart rate recorded during this test is considered a direct measurement of HR Max, offering a personalized benchmark for training intensities.
Conducting the Cooper test
Preparation: Ensure readiness through proper warm-up and hydration. Use a reliable heart rate monitor for accurate data collection.
Execution: Run at the highest sustainable intensity for 12 minutes. This requires a pacing strategy and experience to maximize the distance covered without early fatigue.
Measurement: Record the peak heart rate achieved during the test. This value represents your current HR Max.
Advantages of the Cooper test
Personalization: Directly measures your cardiovascular peak performance, accounting for individual fitness levels, genetics, and environmental factors.
Adaptability: Suitable for athletes of varying fitness levels, offering insights into both cardiovascular capacity and endurance.
Integrating % HR Max into various running training types
Incorporating % HR Max into training involves designing workouts that cater to different running types, each targeting specific physiological adaptations. By strategically varying intensity within % HR Max zones, runners can achieve comprehensive development across aerobic capacity, lactate threshold, and anaerobic power.
Below is an expanded look at how to integrate % HR Max into various run types within a training program.
Easy runs
Purpose:
Enhance aerobic base, promote recovery, and increase fat utilization as a fuel source.
% HR Max Zone:
65-75%.
Application:
Easy runs should feel comfortable and conversational. For an athlete with a HR Max of 190 bpm, this translates to maintaining a heart rate between 124-143 bpm.
These sessions help in building endurance and facilitating recovery on days following hard workouts.
Recovery runs
Purpose:
Facilitate physical recovery from hard training sessions, promote blood circulation to help repair muscle damage, and maintain running frequency and volume without adding significant stress.
% HR Max Zone:
~60%.
Application:
Recovery runs are designed to be very easy, allowing the body to recover while still moving. They should feel effortless, focusing on loosening up the muscles rather than improving fitness.
For an athlete with a HR Max of 190 bpm, maintaining a heart rate of about 114 bpm ensures the run stays within the recovery zone.
These runs are typically shorter in duration than easy runs, emphasizing relaxation and recovery over endurance building.
Tempo runs
Purpose:
Improve lactate threshold (the intensity at which lactate begins to accumulate in the blood), which enhances the body's ability to maintain faster speeds for longer.
% HR Max Zone:
80-89%.
Application:
Tempo runs are conducted at a "comfortably hard" pace, where conversation is possible but laboured.
For a HR Max of 190 bpm, aim for 152-162 bpm.
These runs are typically 20-60 minutes in duration, designed to push the boundary of aerobic and anaerobic systems.
Interval training
Purpose:
Boost VO2 max (maximum oxygen uptake) and improve running economy and speed.
% HR Max Zone:
90-100%.
Application:
Interval training involves short bursts of high-intensity running followed by rest or low-intensity recovery.
For a runner with a 190 bpm HR Max, this means reaching 171-190 bpm during efforts.
Intervals can vary in length (e.g., 400 meters to 1 mile) and are followed by rest periods allowing the heart rate to drop to 60-70% HR Max before the next effort.
Hill repeats
Purpose:
Build strength, improve form, and increase anaerobic power.
% HR Max Zone:
85-95%
Application:
Similar to interval training but performed on an incline, hill repeats enhance muscular endurance and power.
The heart rate should reach the high-intensity zone (162-181 bpm for a 190 bpm HR Max) during the uphill effort, with recovery on the descent.
Long runs
Purpose:
Increase muscular and mental endurance, improve efficiency in utilizing fat as fuel, and enhance aerobic capacity.
% HR Max Zone:
65-75%.
Application:
Long runs are performed at a steady, controlled pace, conducive to endurance development.
For a HR Max of 190 bpm, maintaining a heart rate between 124-143 bpm allows for sustained effort over a longer duration (1-3 hours depending on fitness level and goals).
Fartlek runs
Purpose:
Blend elements of speed work into endurance training in a less structured format.
% HR Max Zone:
Varied across the entire session, mixing low, moderate, and high-intensity efforts.
Application:
Fartlek, meaning "speed play" in Swedish, involves varying pace and intensity spontaneously over a set distance or time. The heart rate fluctuates across different zones, offering a dynamic and versatile workout.
Accuracy of heart rate monitors
Heart rate monitoring is a pivotal component of modern exercise physiology, enabling athletes to train efficiently and effectively by targeting specific heart rate zones.
The accuracy of these monitors, especially when comparing wrist-worn devices to chest straps, is crucial for athletes who rely on precise data to guide their training. Recent advances and research have shed light on the most accurate methods of heart rate monitoring, providing valuable insights for athletes and fitness enthusiasts alike.
Understanding the technology
Heart rate monitors primarily utilize two types of technology: optical (photoplethysmography, or PPG) and electrical (electrocardiography, or ECG).
Wrist-worn devices typically use PPG technology, which estimates heart rate by measuring changes in blood volume under the skin. In contrast, chest straps employ ECG technology, detecting the electrical activity of the heart to measure heart rate directly.
Accuracy of chest straps vs. wrist-worn devices
Chest straps
Chest straps are widely regarded as the gold standard in heart rate monitoring for recreational and professional athletes. The ECG technology they employ offers direct measurement of heart activity, resulting in highly accurate and reliable data.
Numerous studies have validated the precision of chest straps in various conditions and exercise modalities, noting their consistency and closeness to laboratory-grade equipment (4).
Wrist-worn devices
On the other hand, wrist-worn devices, despite their convenience and multi-functionality, can sometimes provide less accurate heart rate readings.
The PPG technology, while sophisticated, can be susceptible to motion artifacts, changes in blood flow due to movement, and interference from ambient light, potentially affecting accuracy. Factors such as device placement, tightness, skin tone, and even tattoo presence can also influence the readings (5).
However, advancements in technology and algorithms have significantly improved the accuracy of wrist-worn devices, making them suitable for general fitness tracking and non-elite training purposes.
For most users, the convenience and additional features (like activity tracking and notifications) of wrist-worn devices offer a compelling trade-off for the slight decrease in heart rate monitoring precision.
Accurate methods and recommendations
For athletes seeking the most accurate heart rate data, particularly for training and performance optimization, chest straps remain the recommended choice.
Their direct measurement technique minimizes errors and provides data quality comparable to medical-grade devices. Athletes and coaches can rely on this data for precise training zone targeting and performance analysis.
Wrist-worn devices, while slightly less accurate, still play a valuable role in the fitness ecosystem. They offer an accessible way for individuals to monitor their physical activity, heart rate trends, and general fitness levels.
For those engaged in less intensive training or those who prioritize convenience and broader health tracking, wrist-worn monitors are an excellent choice.
Moving forward with % HR Max
Incorporating % HR Max into running program design is a science-driven approach that maximizes training efficiency and personalizes workout intensities.
By grounding this methodology in physiological principles, employing accurate calculation methods, and adapting training plans based on empirical data, runners can achieve sustained improvement and peak performance.
Advanced tracking technologies and adherence to scientific guidelines further refine this process, highlighting the dynamic interplay between science and practical application in athletic training.
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References
Londeree, B. R., & Moeschberger, M. L. (1982). Effect of age and other factors on maximal heart rate. Research quarterly for exercise and sport, 53(4), 297-304.
Laursen, P. B., & Jenkins, D. G. (2002). The scientific basis for high-intensity interval training. Sports medicine, 32(1), 53-73.
Tanaka, H., Monahan, K. D., & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the american college of cardiology, 37(1), 153-156.
Wallen, M. P., Gomersall, S. R., Keating, S. E., Wisløff, U., & Coombes, J. S. (2016). Accuracy of heart rate watches: implications for weight management. PloS one, 11(5), e0154420.
Gillinov, S., Etiwy, M., Wang, R., Blackburn, G., Phelan, D., Gillinov, A. M., ... & Desai, M. Y. (2017). Variable accuracy of wearable heart rate monitors during aerobic exercise. Medicine & Science in Sports & Exercise, 49(8), 1697-1703.