We're going to answer the question of why training slower can make you race faster. A lot of runners think that if they run fast they are going to be fast, whilst this is right in so many ways there is such a thing as going too fast, too often which leads to injury, burnout and fatigue. 

Think of it this way, the slower you run, the more miles you can run, and you'll be able to build up a lot slower with more consistency. The reason why running slower could be of a benefit to you is because it is solely responsible for building that aerobic engine.


All races over 800m use more than 60% of your aerobic system compared to that of your anaerobic system. Metabolically 5K is 90% aerobic so it begs the question as to why you would want to do a lot of your training over 70% exertion?

Now, this doesn't mean that you should stop running fast altogether, it's true that just running slowly makes for slower runners. There has to be an element of variety in your training, Matt Fitzgerald wrote a book on just that called 80/20 training in which 80% of your training is easy and 20% of your training is hard.

This makes perfect sense when you put it into a weekly training context. Say you are marathon training and you are planning a 40 miles week, 8 miles of that week (give or take) is going to be high end running. Whether that is your threshold run set or intervals or if you are running two sessions a week aiming to split the mileage up and not make each session too distance intense!

To put easy running into some perspective for you Eluid Kipchoge's easy run pace is 5 minutes per kilometer (8:03 minutes per mile) around 3.5 minutes per mile slower than his marathon pace. How many of you run that slow in proportion to your given race pace?


When running at an anaerobic level, your body relies on glycogen stores in your muscles and liver. During aerobic running, energy is primarily derived from fat stores.

Most athletes have two to three hours of available glycogen stores, but the majority of people will start to feel hungry after 90 minutes of easy activity. Regardless of body type, we all carry fat stores that can fuel more than 100 hours of aerobic activity so it makes total sense to work on utilising those stores than worrying about getting all the gels you can in your system when running a race longer than 90 minutes.

Training easier on an empty stomach can teach your body to use the reserves it has stored rather than using what you just had for breakfast as fuel. I would recommend starting with 20 minutes and building up from there and take some fuel with you just in case.

Not forgetting to mention it also teaches your body to run and be efficient when it has less fuel in its system to burn quickly.


I was and still am a big believer in Phill Maffetone's method of training using the MAF test and maximal aerobic function along with a heart rate monitor. There has to come to a point in your training where you are not worrying about the numbers.

Where heart rate training is concerned, the way I see it is that you are either watching it to see how easy you are running, keeping to a specific heart rate for a certain session (Threshold for an example), see what your heart rate averages for a race, and what your peak HR is for a specific session or again - race.

It teaches you to run slower when you really need too: Time and time again I see runners that are labelling there runs on Strava as an 'easy' run but there are only running about 5 seconds slower than there half marathon pace. THIS IS NOT AN EASY RUN and is a sure recipe for disaster and injury. What a heart rate monitor can do (when you have calculated your zones) is tell you based on your HR how hard you are running, you can also use this as a valuable tool to actually run slower and get the most out of your training.

For those of you without a heart rate monitor it is important to listen to what your body is trying to tell you, is your breathing feeling a little laboured on your easy run?

You literally should be able to breathe in and out through your nose, that's how easy your recovery/easy runs should be. If in doubt use a valuable training tool such as V-dot to calculate your training zones based off recent race performances.

I hope this gives you valuable insight into why training slower can make you faster, feel free to reach out to me on socials if you have any questions!

written by

Marcus Sladden

Digital Marketing Executive from Norwich

Age group: Open

Coach: Self Coached

Strength Training marathon Functional Training 10k half marathon track & field