80/20 Running: Why You Need to Slow Down

The principles of 80/20 running explain why you need to slow down 80% of the time to improve your race speed.

Believe it or not, I used to absolutely HATE running. The great majority of the population hates running too.

80 20 running why you need to slow down

Why do so many people hate running?

Because we make the #1 biggest mistake that will cause EVERYONE to hate running, fail to recover properly, and struggle to increase their miles.

I used to make this mistake on every single run. Every time I ran, my lungs would burn, my legs would get heavy, and I couldn’t run for more than a couple minutes before I felt like I was going to die and had to slow to a walk.

Can you relate??

Since I was in the military, I didn’t have a choice: I had to run (pretty fast) at least once per year for my physical fitness examination. So…I ran in the months leading up to my test to ensure I could pass it.

When my times got slower and slower each year, I got a little concerned. If the slowing trend continued, I would soon fail. Several years into my military career I decided to make a change—I needed to get better at running.

How do you get better at running? Run more!

But how can you possible bear running more when you already hate every minute of it?



Really, the concept is simple. Just run slower more often instead of racing yourself every time. After I started running slower, I discovered the principle of 80/20 Running, which is an actual training practice that the pros use.

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What is 80/20 Running?

80/20 Running is a training philosophy showcased by Matt Fitzerald in his book: 80/20 Running, Run Stronger and Race Faster by Training Slower.

This concept has developed over time by as the most effective way to increase miles and stamina. Stephen Seiler is credited with the discovery of the 80/20 training rule, and Arthur Lydiard came up with the idea that the key to maximum fitness was lots of slow running.

The 80/20 running method will completely shift your training paradigm.

Excerpt from the book:

“The 80/20 Rule promises to revolutionize running (and other endurance sports) in a couple ways. First, it ends the debate over whether a mostly-slow approach or a speed-based approach to training is more effective. No longer will scientists and coaches with a bias for high intensity (or even moderate intensity) be able to steer runners in the wrong direction. Second, by supplying clear numerical targets, Seiler’s discovery makes effective training easier even for runners who are already training more or less the right way. The 80/20 Rule removes the guesswork from the training process. Reaping its benefits is a simple matter of planning your workouts in accordance with the rule and monitoring your running intensity during each workout to ensure you’re where you’re supposed to be.”

Fitzgerald, Matt. (2014).80/20 Running, Run Stronger and Race Faster by Training Slower. New York, New York: Penguin House

The principles of 80/20 running can be summarized as running 80% of your training miles at a slow pace or easy intensity, while only running 20% of your miles at a moderate or high intensity.

The idea behind this philosophy is you need to build stamina before you can build speed. Additionally, the body can only handle so many miles at a moderate or high intensity. However, it CAN handle many more low intensity miles.

I have personally felt this.

Previously, I pushed my pace in every run, only to skip a workout later in the week because I felt like my body was exhausted and it couldn’t handle any more miles. Yet now, I’m increasing my miles and I feel like I could easily fit more miles into the week because my body is able to recover from the slower miles.

Does running slow make you faster?

When I decided I needed to get better at running to keep from failing my physical training tests, I knew something dramatic had to change.

In order to run more, I would need to find a way to enjoy running if I was going to gain any level of consistency necessary for improvement.

I was SUPER frustrated with running because I made the same mistake that makes everyone hate running.

I thought that every training run had to be a personal best. Falsely, I was under the impression that you have to run at or near your goal pace in every workout, or you weren’t pushing yourself enough.

In order to gain consistency in my running, I started by doing one thing: SLOW DOWN.

How could I expect to race faster if I had to keep taking walk breaks? One easy way to cut minutes off my time would simply be to build my stamina so I could keep running for the whole race (or fitness test).

How do you start enjoying running?

The first thing I did was slow down to a pace where I could keep running for 30 minutes. The premise was simple: I ran as slow as I wanted—so slow I barely shuffling my feet—but I had to KEEP running… no walking.

When you start training using this concept, you can do the same thing. Slow down to a comfortable easy pace, then slow down a little more. Run at a pace that is so relaxed, you could run forever.

When I slowed down, something amazing happened.

I actually ENJOYED running. Crazy, right?! From there, I started running 3-4 times per week and found a 5k training plan to follow, along with incorporating my usual strength training.

Then, I learned that most runners don’t run every training run as fast as they race…WHAATTT???

Holy crap, I was doing the right thing? No way…

I used this as a turning point to focus on slowing down, enjoying my running, and improving my capacity to run more miles.

What happens when you forget the 80/20 running rule?

Over time, I forgot about this training philosophy as I got more excited about running and improving my times. As I ran through the next year, I set my sights on my first half marathon, steadily pushing my total mileage up from 12 miles per week to over 20 miles per week.

When I started training for my first half marathon, the premise of 80/20 running was forgotten. I tried to push my pace in all of my runs because the miles weren’t specifically called out as “easy miles.” I figured, the faster I can run in training, the fast I’ll be able to race, right??

The “easy miles” I ran were more like “moderately hard” miles.

As a result, my body was constantly exhausted. I frequently skipped workouts in my training plan because I was too exhausted and opted to sleep rather than run. Plus, I was scared to get injured and told myself I was “listening to when my body needed rest.”

The reality was, my body DID need rest. But it needed active rest and less stressful miles. By slowing down the pace on 80% of my miles, I could’ve built my mileage and still given my body the break it needed.

The #1 mistake that makes everyone hate running. 80/20 running

A Completely Different Training Paradigm Might Make You LOVE Running

Before I started my next half marathon training plan, I came across Matt Fitzgerald’s book and it completely changed my thought paradigm.

He provided so many examples and concrete evidence of how runners benefit more by running slow—truly slow—for 80% of their miles. This book really drove home the premise that in order to run faster, I need to run 80% of my miles truly easy each week.

Basically, for every 5 runs I do, 4 of those runs are an easy effort, and 1 run is a speed workout. This works perfect for me because my training plan calls for 5 runs per week and 1 cross training workout.

Tuesday is usually my speed day, so my week looks like this:

Monday-Easy run

Tuesday-Speed run (Tempo or Repeats)

Wednesday-Easy recovery run


Friday-Easy run

Saturday-Long run

Sunday-Cross train

By running easy 80% of the time, I can get all of my miles in AND save my valuable energy for the other 20% of my miles that make up my speed workouts.

Now, I’m not skipping workouts because of exhaustion. On my first half marathon training plan, I only completed 56/69 workouts, which is around 81%.

After implementing the 80/20 Principle on my training cycle this spring, I took 11 MINUTES off my half marathon time!

I feel better, stronger, more energetic, AND I’m increasing my miles.

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If you’d like to get more into this training philosophy and why it works so well, grab a copy of the book:

Do you love running or hate it? Why?

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Run Happy,


About Me: I’m Alexis, Founder of RunningMyBestLife! I am an avid recreational runner, half marathoner, wife, dog mom, busy professional, downhill skier in Northern Utah. My mission is to help new enthusiasts fall in love with the sport of running. I believe that running is a catalyst to taking control of your life and living your best life by design. Learn More –>

1 thought on “80/20 Running: Why You Need to Slow Down”

  1. I agree with this strategy, too. Building a strong base of miles really makes your breathing better and legs stronger so when you need to run for speed it’s a lot easier.

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