Zone 2 Cardio & Heart Rate Planner (MAF/HRR)

Training “easy” is only useful if it’s the right easy. This tool gives you a realistic Zone 2 range via %HRmax or HRR (Karvonen), shows a MAF cap for context, and turns that into weekly minutes you can actually hit. We also include a rough calorie estimate by modality so you don’t overfuel fantasy workouts.

What you’ll get in seconds

• Zone 2 by HRmax: 60–70% of your calculated or manual HRmax.

• Zone 2 by HRR: 60–70% of your heart-rate reserve added back to resting HR (if you provide RHR).

• MAF reference: a conservative ceiling (180 − age) with a working range (cap − 10 to cap).

• Weekly minutes math: sessions × minutes compared to 150–300 min guidance for moderate activity.

• Calories (rough): modality-based METs × body weight × duration-useful for planning, not bragging.

How to use it (no fluff)

1. Enter age. If you’ve tested HRmax, add it; otherwise choose a formula (Tanaka default, Fox optional).

2. Add resting HR if you want HRR-based zones.

3. Choose sessions per week and minutes per session.

4. Pick a modality (walk, run, cycle, row, elliptical, ruck) and body weight for calorie estimates.

5. Click Build plan. You’ll see Zone 2 by HRmax and HRR, the MAF range, weekly minutes, and calories.

Reality checks (read these)

• Formulas are blunt instruments. If your HRmax looks absurd for your age, use a manual HRmax from a proper test.

• Wrist sensors lie. If your watch says 180 bpm while you’re nose-breathing, it’s the sensor, not a VO₂ max miracle. Tighten the strap or use a chest strap.

• MAF is a ceiling, not gospel. It’s fine for aerobic base, but if it conflicts with your Zone 2, bias easy until fitness catches up.

• Minutes beat perfection. If your life only allows 4 × 35 min, that’s what you train. Consistent “good” trumps occasional “perfect.”

What to do next

Hold a steady pace where conversation is possible, breathing is controlled, and your HR sits inside your Zone 2 (preferably HRR if you provided resting HR). Build to 150–300 min/week. When weekly minutes are easy, nudge duration before pace. Save heroics for Zone 4/5 days.

Fueling sanity
Calories here are estimates—use them to avoid huge swings. If weight is climbing and performance isn’t, you’re likely overshooting intake; if recovery tanks and mood nosedives, you’re likely undershooting. Adjust with data, not hope.

Important: This is not medical advice. If you have cardiovascular disease, are pregnant, or use HR-affecting medications, get cleared by a clinician.

Bottom line: Train boring. Stay in the right easy. Stack minutes. The engine grows.