CardioEngine: HR Zone Training

Zone-based cardio coaching built around your aerobic threshold. Live HR zone guidance, automatic failover between Apple Watch and chest straps.

CardioEngine builds your heart rate zones from your aerobic threshold, not your age.

Most cardio apps tell you to "aim for 60–70% of max HR." That number is derived from your age and tells you almost nothing. Your aerobic threshold is the actual boundary between fat-burning aerobic work and glycolytic effort. CardioEngine finds yours and builds five zones around it.

ZONE-BASED LIVE COACHING Once your workout starts, CardioEngine watches your heart rate and tells you when you drift out of your target zone. Too high? Ease off. Too low? Push a little. No guessing, no manual math.

WORKS WITH YOUR HR MONITOR Connect your Polar, Garmin, Wahoo, or any Bluetooth chest strap. Pair your Apple Watch. CardioEngine reads from whichever source is most reliable — if your watch drops out mid-run, it switches to your chest strap without missing a beat.

YOUR WEEKLY TRAINING PICTURE Set a weekly cardio volume target. CardioEngine totals your zone 2 minutes across every session and shows how far you are from your goal. The dashboard marks each training day so you know exactly where you stand heading into the weekend.

ZONE PROFILE BUILT FOR YOU Your five zones are calibrated from your estimated aerobic and lactate thresholds, not a population average. Your zones update as your fitness changes. A confidence score tells you how solid the estimate is — low score just means you need more workout data.

FASTED CARDIO Fasting raises your heart rate at any given effort level. CardioEngine accounts for this by shifting your zone ceilings down a few beats, so your targets stay meaningful when you're training before breakfast.

WHY ZONE 2 Zone 2 is where mitochondrial adaptations happen. Maffetone and Attia have both written on why most people train too hard and get too little from it. CardioEngine keeps you in that range.

• Live zone coaching during workouts • Bluetooth HR monitor + Apple Watch support with automatic failover • Personalized zone profile from your aerobic threshold • Weekly volume tracking with session history • Fasted cardio mode • Treadmill, stationary bike, recumbent bike, rower, stair stepper, and elliptical • watchOS companion app