Can I hold Zone 2 without a heart-rate monitor?

It is possible but less accurate. Use the talk test, nasal breathing, and the MAF calculation as guardrails to stay near aerobic effort.

What should I do when my heart rate fluctuates a lot?

Track sleep, temperature, caffeine, and stress alongside HRV metrics to understand the cause and adjust training load.

Is Zone 2 training alone enough?

Build your aerobic base with Zone 2, but add LT, tempo, interval, or hill workouts every 6–8 weeks to progress VO₂max and race readiness.

Heart Rate Toolkit

Dial in Zone 2, MAF, and LT heart-rate zones with one workflow.

Compare 220-age, Tanaka, and custom max HR values, overlay Karvonen (HRR) results, and connect the output to 80/20 mileage planning. Consistent aerobic control keeps easy days easy—and makes the hard days count.

Start the HR calculation Read the Zone 2 playbook

Max HR comparisons Review 220-age, Tanaka, and custom entries side by side before locking in training zones.

Zone table & MAF Get bpm, %HRmax, and %HRR for Zones 1–5 plus an automatically adjusted MAF 180 result.

LT & recovery pairing Cross-check LT output to schedule tempo runs and assign true recovery days without guesswork.

💓 Zone 2 heart-rate calculator

Enter age and resting HR to calculate Zone 1–5, MAF 180, and weekly 80/20 mileage recommendations.

Age (years) Resting HR (RHR)

🎯 MAF 180 formula

Choose the modifier that best fits your health history and training consistency.

MAF condition modifier

Recovering from illness/surgery or managing chronic conditions Frequent niggles, inconsistent training, high stress Consistent for the past 2 years with no major setbacks Elite-level endurance history with annual performance gains

Maximum aerobic HR (MAF)

— bpm

Aim for MAF HR − 10 to MAF HR during easy aerobic runs.

📊 Full HR zone table

Max HR estimate

220 − age 208 − 0.7 × age Custom max HR

Custom max HR Zone method Zone 2 preset (%)

Zone 2 (aerobic base)

— bpm

—

Calculated max HR

— bpm

Zone	% of max/HRR	bpm range	Primary purpose
Enter your age to view the table

Training notes

80/20 distribution

Keep 70–80% of weekly mileage in Zone 1–2 for aerobic development, with the remaining 20% dedicated to tempo, LT, and VO₂max work.

Pair with LT

Compare the Zone 2 ceiling and LT HR to plan tempos and cruise intervals that build threshold without overshooting recovery capacity.

Recovery monitor

If easy-day HR drifts 5+ bpm above normal, check sleep, hydration, and HRV to decide whether to back off intensity.

Multisport friendly

Karvonen outputs work well for cycling, rowing, or swimming cross-training when you track resting HR accurately.

Calculate my Zone 2 →

Core terms

MAF 180 formula: Dr. Phil Maffetone’s method that subtracts your age from 180 (with small adjustments) to estimate an aerobic ceiling for Zone 2.
Karvonen (HRR): Uses heart rate reserve—the gap between max and resting HR—to produce personalised training zones.
Zone 2: The aerobic base range where conversation stays easy; keeping 60–80% of weekly mileage here steadily builds endurance.

Weekly recipe ideas

Base focus (4 weeks) — Zone 2 runs three times a week, strides, and one light tempo touch to raise aerobic capacity.
LT bridge — Add 2 × 15′ tempo intervals while keeping mileage aerobic to progress toward race-specific prep.
Recovery reset — When HRV dips, push Zone 1–2 to 90% volume, keep strides, and monitor morning HR until it normalises.

Companion tools

Match treadmill speeds to your HR zones Update lactate threshold pace & HR Strength & recovery checklist

Dial in Zone 2, MAF, and LT heart-rate zones with one workflow.

💓 Zone 2 heart-rate calculator

How to use the HR calculator

🎯 MAF 180 formula

📊 Full HR zone table

Training notes

80/20 distribution

Pair with LT

Recovery monitor

Multisport friendly