Heart Rate & Fat-Max Zones
Karvonen & Tanaka heart-rate zones with your Zone 2 aerobic sweet spot.
Find your personalized Zone 2 aerobic base & Fat-Max heart-rate window using the Tanaka Max-HR equation and Karvonen Heart Rate Reserve (HRR) method.
How this is calculated
Methodology & sources
- Age-predicted maximum heart rate (HRmax = 208 − 0.7 × age): Tanaka H, Monahan KD, Seals DR — Journal of the American College of Cardiology (2001)
- Heart Rate Reserve (HRR) training zones: Karvonen MJ, Kentala E, Mustala O — Annales Medicinae Experimentalis et Biologiae Fenniae (1957)
Privacy — how your data is handled
All math runs in your browser on your device. Nothing you type is sent to a server,
and saved results live only in this browser's local storage. Tools that use live
public data (food databases, weather) request only what they need to display.
👟 Practical toolkit tip — Simple Pocket Pedometer or Wrist Step Counter
Why it helps: Tracking daily step volume (7,500–10,000 steps/day) prevents subconscious NEAT drop-off when you are in a calorie deficit.
Pro tip: A 15-minute brisk walk after dinner adds ~1,600 steps and blunts post-meal blood glucose spikes.