Driftline Analytics
The science layer missing from every wearable.
TrueZone is the first unified model of human physiology. Three parameters extracted from ordinary heart rate data. Every fitness and metabolic metric derived. No lab required.
28,000+ validated sessionsPatent protection to 2045No lab required
The Model
Three parameters. Everything derived.
TrueZone fits a physiological ODE to your heart rate signal using Bayesian accumulation. From three converged parameters, the entire fitness and metabolic profile follows.
Endurance
Aerobic durability, fat-oxidation capacity, mitochondrial density, and slow-twitch profile expressed as one trackable parameter.
Max Speed
The top of the individual intensity scale. Thresholds, race predictions, and training paces are anchored against it.
HRmax
Model-predicted maximum heart rate from submaximal kinetics, used to align the cardiovascular response to the speed scale.
Derived from E, V, and P
f(E, V, P) → profile
How It Works
Read the full method →Stream
Ordinary heart rate plus speed or power, from any wearable. No new sensors, no test protocols, no lab visits.
Fit
A physiological ODE is fitted to every session. Bayesian memory accumulates evidence across the training history.
Converge
E, Vmax, and HRmax stabilize per athlete. The full fitness and metabolic profile follows deterministically.
Applications
One model. Every sport.
The same three-parameter architecture fits running, cycling, and team sports without sport-specific tuning. Each application page tells the full story: problem, solution, validation.
Beyond Sport
Metabolic health from heart rate.
TrueZone's metabolic scale tracks metabolic fitness (MFI), metabolic strain (RZI), and glycolytic power—with strong correlations to glycemic control and insulin sensitivity. It also derives VO₂max from the same model.
Metabolic Fitness Index
Quantifies metabolic flexibility, fat oxidation efficiency, and glucose response.
Metabolic Zones
Track substrate strain and metabolic inflexibility in obesity, ageing, and insulin resistance.
Energy Expenditure
Separates basal, activity, and feeding components from HR analytics.
Energy Intake
Pilot-scale modelling of postprandial thermic effect from HR signal dynamics.
Food tracking →
Driftline's work lays the groundwork for next-generation metabolic monitoring solutions that support healthier aging and improved population health.
Willum Thor Thorsson
Former Minister of Health, Iceland (2021–2024)
For Platform Partners
Today's wearables measure heart rate with millisecond precision. They still can't read what it means.
Across Garmin, Apple, WHOOP, Polar, COROS, and every other platform, the science layer is the same: a VO₂max estimate, fixed percentage zones, and heuristic recovery scores. No individualized thresholds. No endurance modelling. No metabolic insight. TrueZone is the missing layer—an SDK that turns existing heart rate data into real physiology.
{
"E": 0.74, // endurance, 0–1
"Vmax": 5.42, // m/s
"HRmax": 187, // bpm
"derived": {
"vo2max": 52.1,
"lt1_hr": 148,
"lt2_hr": 171,
"zones": [ /* individualized */ ],
"...": "60+ metrics"
}
}