Heart rate analysis

Cracking the heart rate code.

Driftline's patent pending heart rate analytics divide the exercise-induced heart rate curve into components, reflecting the use of fuels (creatine, carbs, and fats) by different energy systems within different type aerobic muscle fibers (see graph below).

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Driftline proudly claims that the enigma of the heart rate code has finally been cracked!

A new threshold system

The five exercise thresholds.

Driftline is presenting the Exercise Threshold System, a true breakthrough in exercise science. Human muscle consists of three major types of muscle fibers, i.e., slow oxidative fibers, fast oxidative/glycolytic fibers, and fast glycolytic fibers. With increasing exercise intensity, the muscle recruits progressively faster fibers and transitions are reflected in five evenly spaced exercise thresholds (T1 - T5).

024681012141618202224262830T1T2T3T4T5ThresholdsT1 - T5Speed thresholds (T1 - T5) in km/h

T1 is named Endurance threshold, since it reflects the ratio of slow, aerobic muscle fibers and determines the individual's aerobic endurance. T2 is named Critical threshold, since it is critical for endurance performance and coincides with this familiar scientific threshold. T5 is named Max speed threshold, since it represents the individual's absolute maximum speed.

The discovery of endurance

The first true measure of quantified aerobic endurance.

Driftline's new Endurance parameter scales between 0 - 100% and reflects the proportion of slow, aerobic muscle fibers. A high-endurance runner will get good mileage from glucose stores and produce competitive race times over long distances. In short, Endurance is fuel preservation through muscle efficiency.

024681012141618202224262830T1T2T3T4T550%Endurance30.0 km/hMax speed

The speedometer above shows how Endurance reflects the alignment of exercise thresholds. Use the Endurance slider to explore the threshold alignment. Endurance is minimized when thresholds are in distal alignment (T1 equals zero) and maximized when they are in proximal alignment (T1 equals half of T5). The discovery of Endurance is poised to become an important milestone in exercise physiology.

Maximum running speed

Finding the maximum speed.

Maximum speed is one of two the major performance factors for running, the other being Endurance. Based on Driftline's principle of threshold alignment, the maximum speed is easily extrapolated, since it equals the highest of the five exercise thresholds (T5).

Max speed30.0 kph

The speedometer above shows the threshold speed levels for the specific case of 50% endurance. The maximum speed is always fixed as the T5 threshold. You can use the Max speed slider to see how the other thresholds are directly related to the max speed. Driftline has discovered how to measure maximum running speed indirectly, based on a leisurely walk.

The Endurometer

The dashboard to your engine.

The Endurometer is your personal running speedometer. It displays your vital fitness statistics, such as Endurance, max speed, exercise thresholds and performance zones. You can use the sliders to explore how the running fitness is dictated by max speed and Endurance.

024681012141618202224262830T1T2T3T4T550%Endurance30.0 km/hMax speed
Max speed30.0 kph


A universal fitness metric.

The Runscore was developed by Driftline to facilitate a fair comparison of all runners, independent of age, gender, or runner type. A score is calculated for every race distance and the highest score equals the Runscore, as shown on the bar diagram below. You can use the sliders to see how the scores are affected by Max speed and Endurance.

Max speed25.0 kph
Age25 years old



The World Athletic scoring tables were extended to accommodate the scoring of runners on a scale of 0 - 10. World-class runners at any distance may, however, tip the scale and a world-record performance may produce a Runscore of around 11. Please note that the Runscore is based on the estimated maximum speed for street running and that sprinters will reach higher speeds on running tracks.

Prediction of race times

Endurance and max speed dictate performance over any given distance. Use the time machine to predict your own race times.

Maximum heart rate

Finding HRmax.

Driftline is also presenting the first true measure of maximum heart rate (HRmax). Age-predicted HRmax in current models outside of Driftline is extremely inaccurate and even all-out lab tests typically underestimate HRmax. The Driftline heart rate kinetics show that a true HRmax can only be reached when exercising to exhaustion at critical threshold speed, as indicated in the graph below.

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The graph shows an example of how a true HRmax of 184 bpm is reached at critical threshold speed (15.0 kph in this example), while lower maximum heart rates are reached at lower or higher speeds. Driftline calculates HRmax based on glucose store depletion, and only requires an easy run or brisk walk to identify HRmax.


Metabolic profiling.

Driftline's metabolic profiling can potentially increase the accuracy of energy expenditure calculations. These include metabolic rates, such as fat- and carb oxidation, calorie expenditure and gas exchange (VO2/VCO2), at rest and any given exercise intensity.

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Metabolic profiling can potentially allow calorie intake to be calculated from thermogenic heart rate elevation. Fat oxidation is shown to be maximized (Fatmax) at T1 threshold intensity, as shown on the graph.

Cardiorespiratory fitness

Metabolic scaling of VO2max.

The ageing-related decline in cardiorespiratory fitness (CRF) is a major cause of mortality and disease in the world's aging population. Maximum oxygen uptake (VO2max) is a universally accepted measure of CRF but has a strong gender-bias favoring men (see graph below).

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Driftline offers metabolically scaled VO2max (mVO2max), an unbiased and realistic CRF score.

Post-exercise recovery

Fine-tuned simulation of heart rate recovery.

The shape of the heart rate curve during recovery from exercise, reflects the replenishment of depleted fuel stores (creatine, glycogen, and lipids), the removal of blood lactate, and the restoration of oxygen stores (in myoglobin and hemoglobin).

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Driftline's heart rate model closely predicts recovery time, which depends on the duration and intensity of the exercise.

Patented analytics

Pending EPO patent application.

Driftline's international patent application titled A method and system for determining exercise parameters including aerobic endurance based on heart rate curve analysis has been accepted by the European patent office (EPO).

Still curious?