Free Zone 2 Heart Rate Calculator (+ Talk Test)

What is zone 2?

Zone 2 is the hardest steady effort you can hold while your muscles still clear the lactate they make. Peter Attia puts it at about 2 millimoles of lactate per liter of blood in fit people.

In a lab you find it with a blood lactate meter or a breath test. At home you estimate it from your heart rate, then check it with how you breathe and talk.

Your watch's zone 2 isn't Attia's zone 2

Phil Maffetone

Zone 2 for a 40-year-old

Under 140 bpm

Where it comes from

180 minus your age, with 1 of 4 adjustments

Your watch

Zone 2 for a 40-year-old

111 to 130 bpm

Where it comes from

60 to 70% of max, Garmin's zone table

Peter Attia

Zone 2 for a 40-year-old

130 to 157 bpm

Where it comes from

About 70 to 85% of a real max, Outlive

Method	Zone 2 for a 40-year-old	Where it comes from
Phil Maffetone	Under 140 bpm	180 minus your age, with 1 of 4 adjustments
Your watch	111 to 130 bpm	60 to 70% of max, Garmin's zone table
Peter Attia	130 to 157 bpm	About 70 to 85% of a real max, Outlive

The ranges are for NTNU's estimated max of 185 bpm at 40. Your own measured max moves the watch and Attia numbers.

A watch's zones are shares of your max heart rate, so its zone 2 is gentle by design. Attia's zone 2 is the top of your easy work, so it sits higher.

The talk test

Attia's check without a lactate meter: you can talk in full sentences, but you'd rather not carry on a conversation.

If you can chat easily, go a little harder. If you can only get out a few words, back off.

How to find your real max heart rate

Every percentage above starts from your max. A formula is only a guess for someone your age.

NTNU's formula, 211 minus 0.64 times your age, came from measuring thousands of Norwegians. A max from a hard, all-out test beats it, so the calculator takes yours if you know it.

Maffetone's four adjustments

Maffetone starts from 180 minus your age, then moves it by your training lately:

• Recovering – a major illness or surgery, rehab, regular medication or burnout: minus 10.
• Setback or starting – injured, not improving, often sick, allergies or asthma, or just starting: minus 5.
• Steady – training at least 4 times a week for up to 2 years without those problems: no change.
• Progressing – more than 2 years of training, improving and without injury: plus 5.

At 16 and under, he uses 165 for everyone.

How much zone 2 a week

That's Attia's plan in Outlive. A bike, a brisk walk uphill, rowing or easy swimming all work.

The people behind the numbers

Person	What they say about zone 2
Peter Attia	The talk test: you can talk, but you'd rather not chat
Phil Maffetone	Train at or under 180 minus your age, adjusted

Outlive

D

by Dr. Peter Attia

Outlive by Dr. Peter Attia breaks down the most effective strategies for long-term health and performance, covering exercise, nutrition, sleep, and emotional wellbeing to add years to your life.

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Estimate your VO2 max with the VO2 max calculator, see your fitness line to 90 with the fitness age calculator, and take the full longevity test.