CardiacDriftLive

See your aerobic fitness fade in real time — before your pace does. CardiacDriftLive is a Garmin Connect IQ data field that tracks cardiac drift (aerobic decoupling, Pa:Hr) live during your run or ride. Instead of just showing a rising heart rate — which is normal physiology — it shows whether your heart-rate-to-pace relationship is holding up: the actionable signal for aerobic fitness and pacing. WHAT YOU SEE • A big percentage: your current decoupling vs. your pace-matched baseline heart rate • The entire field fills like a fuel gauge — green (stable), yellow (early fatigue), red (significant drift) — so you can read your status at a glance, without having to focus on the exact number, with a bold marker line right at the fill boundary • A heart-rate line (with a heart icon) showing current vs. baseline HR • Clean, solid-color text that automatically adapts to your field's background — white on black, black on white — for maximum readability • Optional mini-bar and session-max-drift label for a precise 0–10 % reading (both off by default, enable them in settings) HOW IT WORKS After a configurable warm-up, the field establishes a pace-matched baseline heart rate, then continuously compares it to your rolling 60-second HR average. Grade-adjusted pace keeps the comparison fair on rolling terrain. Works indoors too (trainer / treadmill), with or without a speed sensor. FULLY CONFIGURABLE • Warm-up duration • Measurement window • Green/yellow and yellow/red thresholds • Optional heat-stress threshold adjustment (off by default) • Optional mini-bar and max-drift label (off by default) NOW ON GARMIN EDGE TOO Runs not only on Garmin watches (Fenix 6/7, Epix Gen 2, Forerunner 255/265/955/965, Venu 2/3, Instinct 2, D2 Mach 1), but now also on Garmin Edge cycling computers (520 Plus, 530/540/550, 830/840/850, 1030/1030 Plus, 1040/1050, Explore/Explore 2, MTB). WHY THIS METRIC Heart rate normally drifts upward over time at constant effort — that's not a problem. What matters is whether your pace-to-HR ratio holds up (Friel / TrainingPeaks "decoupling"). Trained athletes typically stay under 3 % over 90+ minutes; above 5–8 % suggests checking pacing, fueling, hydration, or heat. SOURCES 1. Coyle & González-Alonso, Exerc Sport Sci Rev 2001 2. Wingo et al., Exerc Sport Sci Rev 2012 3. Friel / TrainingPeaks (Pa:Hr / EF) 4. Maunder et al., Sports Med 2021 5. Seiler, Int J Sports Physiol Perform 2010

Version 0.3 – Now on Garmin Edge • Official support for Garmin Edge cycling computers (520 Plus, 530/540/550, 830/840/850, 1030/1030 Plus, 1040/1050, Explore/Explore 2, MTB), in addition to watche Version 0.2 – Readability polish** • Tighter spacing between the percentage number and the % sign, so it reads as one clean value • Bigger, easier-to-read heart-rate line • Heart icon now vertically centered on the heart-rate line (previously sat slightly too low) Version 0.1 – Initial release** • Live cardiac drift (Pa:Hr) calculation with pace-matched baseline heart rate • Full-field fuel-gauge fill (green/yellow/red) • Heart-rate line with heart icon showing current vs. baseline HR • Session maximum drift value display • Mini-bar for precise 0–10 % reading • Grade-adjusted pace for fair tracking on rolling terrain • Indoor activity support (trainer / treadmill) • Configurable warm-up duration, measurement window, and thresholds • Optional heat-stress adjustment, off by default