Heart rate zone training is easy. Just take the square root of your age, multiply it by the derivative of zone 7, and add the cosine of the tangent and ...

Screw it. There has to be an easy way to do this!

If you've read up on heart rate zone training, your head has probably exploded multiple times when confronted with mathematical formulas and complex zone classifications.

I've seen actual heart rate training plans with as many as seven zones. Seven! I promise you, that is more than twice as many as you actually need.

Personally, I like to keep my heart rate zone training stupid simple. In this post, I'll show you how to do train with:

• Just 3 zones

• No heart rate monitor

• No math

And the crazy thing is, unless you are in the top 1 percent of your sport and training for the Olympics, this simple system works just as well as the rocket science version. So let's get started.

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Goodbye max heart rate formulas

If you've done heart rate zone training in the past, you've probably subtracted your age from 220 to find your max heart rate, then used it to calculate your zones.

However, human heart rates vary quite a bit. Becky, age 20, might have a max heart rate of 200. But so might Trish, age 40.

In fact, research suggests that the 220-minus-age heart rate formula has a standard deviation of 12 heartbeats! This means that for 44 percent of the population, the predicted max heart rate will be off by 12 beats or more.

It's also worth noting that most max heart rate formulas are based on the general population, not athletes or fitness enthusiasts. People who exercise regularly actually experience less age-related decline in their max heart rates.

And finally, your max heart rate varies by sport. You may have different max heart rates for running, cycling, hiking, and hiking at altitude.

EXTRA CREDIT: There are actually some better max heart rate formulas with standard deviations as low as 7. Check out this Runner's World article for more info. But honestly, SD 7 is still a lot of variability!

Hello perceived exertion

So if you don't use heart rate to measure your workout intensity, what can you use instead?

My favorite tool for measuring exercise intensity is called Ratings of Perceived Exertion (RPE). It's a 0–10 effort scale, with zero representing rest and 10 representing the hardest possible effort.

Here's a breakdown:

0 - Rest, zero effort

1 - Very light

2 - Light

3 - Moderate

4 - Somewhat hard

5 - Hard

6

7 - Very hard

8

9

10 - Very, very hard; all-out effort

A big advantage of RPE is that it measures actual effort. Heart rate usually corresponds with effort — but not always! Dehydration, heat, overtraining, and certain medications can all change the heart rate response to exercise. In these cases, it's important to pay attention to how the body actually feels (RPE!) in order to exercise safely.

Research suggests that most people rate themselves consistently on RPE, and that it can be a useful tool for zone training. I personally like to use RPE in combination with my heart rate monitor, because it gives me more information. But you can also get a great cardio workout with RPE alone.

A simplified guide to heart rate zones

If you currently have 7 zones programmed into your heart rate monitor, I want you to take a deep breath and step away from the Kool-Aide!

Fretting over all of those zones is probably cutting into your workout time without giving you any extra benefits. (Seriously, what is your body doing in Zone 4a that it's not doing in Zone 4b? Probably not much.)

Here's the truth. As exercise intensity increases, your body goes through two physiological shifts that create three intensity zones. These three zones are all you need to worry about.

Here's how they break down:

Zone 1

Also known as: aerobic zone, fat-burning zone.

RPE: 1-4

Other markers: Nose breathing is comfortable and quiet, and you are able to carry on a conversation while exercising. Near the top of this zone, you will be able to talk, but singing will become difficult. Breathing deepens and speeds up slightly.

What's happening in your body: When you are exercising in this zone, your cells are using fat as their primary fuel source. The process of converting fat to energy is called aerobic metabolism. It's extremely efficient and creates very few waste products.

How long can you go? Once you build some basic fitness, you will be able to exercise pretty much forever in Zone 1.

Use it to your advantage: For maximum endurance on a hike, run, or climb, try to hang out in Zone 1 as much as possible. You will feel better, and you will be able to rely on your body's nearly unlimited fat stores for fuel.

Zone 1 training tips

• For endurance athletes like hikers, backpackers, and trail runners, 70 to 80 percent of your training should happen in Zone 1.

• For best results, exercise near the top of this zone, at the effort level where talking starts to get difficult.

• Your program should include one long Zone 1 workout per week that represents 30 to 50 percent of your total weekly training time.

• The aerobic system responds slowly to training, so you may not see changes right away. But after a few weeks, you should notice that you can hike faster and run harder without feeling winded.

Zone 2

Also known as: Tempo zone, lactate threshold zone, the black hole.

RPE: 5–7

Other markers: Breathing becomes noticeably faster. Nose breathing becomes noisy and difficult to sustain. Conversation becomes difficult, though you can still say a few words at a time between breaths.

What's happening in your body: Your cells have shifted from burning fat for fuel to a combination of fat and sugar.

The process of converting sugar to energy is called anaerobic metabolism. This type of metabolism creates acid as a byproduct. Acid irritates your muscles and makes you feel tired.

In Zone 2, your body can eliminate much of the acid your cells create through your lungs, which is one reason breathing speeds up.

How long can you go? Up to 3 hours, for well trained athletes. However, when you're burning sugar for energy, you run the risk of exhausting your carbohydrate stores and hitting the wall or "bonking."

Use it to your advantage: Training near the top of Zone 2 helps your body to become more efficient at eliminating acid. Your cells can also become more tolerant of acid, allowing you to exercise for longer at high intensity.

Zone 2 training tips

• Beginners and casual exercisers should spend 20–30 percent of their workout time in Zone 2.

• Advanced exercisers and competitive athletes should spend about 10–20 percent of their workout time in Zone 2.

• The top of Zone 2 is called the lactate threshold. Exercising just below the lactate threshold will help your body to eliminate acid more efficiently. Over time, your lactate threshold will increase, allowing you to exercise harder for longer.

• Zone 2 workouts can be steady-state (for example, a tempo run) or done in intervals. Zone 2 intervals typically last 5 to 20 minutes. Gradually work your way up to 40 minutes per session. (For example, 8 x 5 min. intervals). For more info, see my interval training blog post.

• Use carbo loading before long Zone 2 races, hikes, and workouts to increase your fuel stores and prevent bonking.

Zone 3

Also known as: Anaerobic zone, high intensity interval training (HIIT)

RPE: 8-10

Other markers: Gasping, breathing becomes faster and shallower, talking is impossible or limited to a word or two at a time.

What's happening in your body: Your body is primary burning sugar for fuel (anaerobic metabolism). As a result, acid is accumulating in your blood faster than you can eliminate it through respiration. You may notice marked fatigue and burning in your muscles.

How long can you go? In this zone, performance declines exponentially with rising intensity. When well-trained, you may be able to go for 30 to 60 minutes at RPE 8. But you will probably not be able to sustain RPE 10 for more than a few seconds.

Use it to your advantage: Zone 3 interval training is probably one of the most efficient ways to burn fat and lose weight. Intense exercise gives your metabolism a boost that lasts for several hours. Research suggests Zone 3 training can also increase your comfort and performance at high altitude.

Zone 3 training tips

• If you're new to working out or coming back from a break, take time to establish basic fitness before beginning Zone 3 training. You should be exercising 5–7 hours a week before beginning Zone 3 workouts.

• Depending on your goals, Zone 3 workouts may make up 0 to 20 percent of your training time.

• Zone 3 training is typically done as interval workouts. Zone 3 intervals can last from 30 seconds to 3 minutes. Gradually work your way up to 15 minutes of high intensity exercise per session. (For example, 5 x 3 min. intervals.)

Sample Workout Plan

So how to you put together a week of heart rate zone training? Here's a sample workout plan for Becky who's climbing Mt. Elbert in about 4 weeks. She started with simple walking workouts and gradually increased her weekly cardio time. Two weeks ago, she started Zone 3 workouts.

Here's how her training week breaks down:

Monday

50 min. aerobics class with weights (Zone 2)

Tuesday

50 min. hike after work (Zone 1)

Wednesday

REST

Thursday

50 min. run with 10 x 1 min. hill repeats (Zone 3)

Friday

30 min. easy strength training circuit (Zone 1)

Saturday

180 min. hiking with a 20 lb. day pack (Zone 1)

Sunday

REST

Need help making your training plan?

My FREE Training Plan Workbook walks you through a simple, six-step process to help you design a fitness program that gets results. Fill out the form below to get your copy.

There you have it. My stupid simple approach to heart rate zone training.

How do you make training simple? Comment below to share.

Originally published August 9, 2019.