How You’re Screwing Up Your Long Runs (& How To Get It Right)

Why they're important, what people get wrong, & how to do them perfectly.

Many runners are conflicted or confused about the advice that long runs should normally be done at a slow and conversational pace – in this post, I’m going to dig into the details and reasoning behind this.

Long runs are easily the most popular topic that runners email me about.

As an online running coach, I get emails every day from runners in training – whether for a half marathon, marathon, or ultramarathon – asking about how they should do their long runs.

(You can check out my more comprehensive Long Run article here.)

The most common question is something along the lines of:

“Hey Thomas,

I’m hoping you could clarify something for me.

My training is going well and I’m following training plan A B C. I’m following the advice that I should be doing my long training runs at a slow, conversational pace. However, this almost feels too easy – and leaves me concerned that on my race day, I won’t be able to run the full distance at my target pace… I’ll be too accustomed to running slow. What should I do?”

people's feet in a running race

The Purpose of Long Runs

Long runs exist to increase your endurance (cardiovascular strength, muscular development, and mitochondria increase – more specifics here).

This is so that come race day, your body is adapted to go the entire distance.

Simple so far, right?

For beginner and intermediate runners (i.e. those of us without 5+ years of steady distance running under our belts), going out for long runs each weekend isn’t something our body is accustomed to.

Add to this the fact that these long runs aren’t taking place in a vacuum – they are part of a structured, but at times intense, training schedule.

This means that sometimes you’ll rock up to your long runs and already be sore with tired legs.

This then further means that you’ll almost certainly be sore and tired the day after each long run – when you’ve likely got another workout scheduled.

Side note: as you get into longer long runs, you should be mindful of runner’s nipple – chafing that begins to irritate after hours of running!

two people running up stairs

Balancing Training Load with Intensity

Your training plan needs to get you race-ready by developing your running ability, speed, and endurance.

However, combining speed + endurance on your long runs can be exhausting.

It may be maintainable for a few weeks, but over a 3-5 month training period your body doesn’t get much of an opportunity to recover with back-to-back intense runs.

Gradually aches, strains, fatigue, and injury begin to manifest.

That’s why the accepted practice for marathon training is to remove any intensity from your long runs.

Remember, the purpose of these longer runs is simply to increase endurance.

If you parse out speed, all of the required benefits can be gained by running your long runs at a slow, manageable pace whilst minimizing the risk of injury.

Two Distinct ‘Muscles’ – Speed and Endurance

The analogy I use when explaining this to runners is to imagine that ‘speed‘ and ‘endurance‘ are two distinct muscles.

You can choose to try and train them together by doing long runs at your race pace, but it will leave you exhausted and take longer to recover from.

Alternatively, you can isolate each of these muscles and train them separately.

In other words – do short race pace runs through the week, and a long run at the weekend.

This way you’re not over-taxing your body at any one point, and you’re spreading the training load over the week.

Now, if you’ve been training for a long time and your body is already adapted to race pace long runs, you’re in a different camp. However, for the majority of runners in training, long easy runs represent a new physical challenge and therefore should be treated with respect.

a person running up stairs

Maintaining Race Pace on Race Day

“But how will I know that I can run long and fast come race day?”

Excellent question.

Some runners get understandably nervous about the ‘slow and steady’ long run approach, as it means that race day will be the first time they actually do a long run at race pace.

There are a couple of remedies to this.

First, it’s fine to do a few long runs at your target race pace. I’d recommend no more than one every 3 to 4 weeks; and be mindful that your body may need extra time to recover afterwards.

Second, you can incorporate Fast Finish long runs; these are normal long runs where you run the last 30% of the run at an increased pace – not necessarily race pace, but faster than your regular pace.

An important point to bear in mind is that your race day performance is almost always better than any training run.

Your body is better rested and tapered, you’re psychologically primed, you feel the adrenaline of the event, you may have fuelled better and rested more, and you will feel the support of other runners and crowds.

It’s natural to feel nervous and doubt your potential, but you should feel reassured that you’re very likely to be strong on race day.

a person checking their running watch

Key Takeaways

To summarize:

  • The majority of long-distance runners aren’t well enough adapted to run their long runs at a fast pace or race pace. Doing so places too much strain on their bodies during an already busy training schedule, and can lead to marathon training burnout.
  • Due to this, the best solution for balancing training vs the risk of overtraining is to perform the majority of long runs at a slow, conversational, and easy pace. The runner still gets all the advantages of improving their endurance but at a lower intensity.
  • Experienced runners can vary their long-run pace more than beginner/intermediate runners or first-time marathon runners.
  • Runners get nervous about not performing any long runs at their target marathon pace; it’s suggested that these runners do a faster long run every 3-4 weeks maximum, and preferably during a step-back week.
  • Fast-finish long runs are an effective tool for combining long runs and speed, with less risk of overtraining, fatigue, or injury.
a person checking their running watch


How Long Should My Longest Long Run Be?

Half Marathon

The longest you are likely to run in a single run during your training is 12 miles (19.31 km), which you will run towards the end of your training program. You will not usually run the full half marathon race distance until race day.

In terms of weekly mileage, our plans generally start at 15 miles (24 km) per week or less, and peak around 30 miles (48 km) per week towards the end of the training before tapering down for race day.


Most marathon training plans are unlikely to have you running much more than 20 miles (32.2 km) for your longest run during your training. You will not usually run the full marathon race distance until race day.

In terms of weekly mileage, most plans start with between 10 to 20 miles (16-32 km) per week, depending on running ability. Beginner plans generally reach around 35-40 miles per week (56-64 km), but highly advanced runners may run 100+ miles a week during their training.

How Do I Stay Fueled During Long Runs?

Carbohydrates are key to replenishing your glycogen stores and preventing you from hitting the wall or ‘bonking’.

Energy gels and other easily digestible carbs are recommended to avoid stomach upset while running.

Check out our guide on fueling before and during long runs for more.

Final Thoughts

Clearly, it’s important to balance your short training runs with longer slower runs and have a well-rounded training program.

Whether it’s your first marathon or you’ve crossed that 26.21-mile run finish line many times before, we have customizable training plans for all abilities, road-tested by thousands of runners, with guidance included on everything from training long slow distances to short runs, speed work, and more.

Photo of author
Thomas Watson is an ultra-runner, UESCA-certified running coach, and the founder of MarathonHandbook.com. His work has been featured in Runner's World, Livestrong.com, MapMyRun, and many other running publications. He likes running interesting races and playing with his two tiny kids. More at his bio.

4 thoughts on “How You’re Screwing Up Your Long Runs (& How To Get It Right)”

  1. Thanks for the information! The suggestion for a faster long run no more than every 3/4 weeks and the faster finish seem like great compromises to “scratch the itch” that sometimes comes in the middle of training.

  2. Seems to be a Great suggestion what Thomas suggested. While I have experienced what the fatigue/ burnout is to the body by doing little to higher intense long runs and then to get back to training the following week, I’m very keen to try the 70% slow conversational pace and remaining 30% race pace… i know i’m not there yet to try even the monthly once race pace long runs without ending up avg. BPM touching the roof

  3. Thanks for the suggestion by Thomas. While I have experienced fatigue/ burnout mean doing intense long runs, I’m very much keen to try the 70% slow initially & 30% race pace to finish .. I know I’m not there yet to try monthly once long runs with race pace as I know my BPM touches the roof


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.