What it takes to Run a sub-3hr Marathon | The Numbers AND The Workouts

“I want to run sub 3hrs. Is that realistic? “

I hear the 3hr marathon goal thrown around A LOT. A large pool of runners I work with are 35-45 year old working professionals. They come to me and say, “I want to run sub 3hrs. Is that realistic?” They’re often concerned they might have left it too late.

Here’s what you need to be able to do for a sub-3hr marathon goal to be realistic.

The first number you need to look at is your threshold pace. You want to have a threshold of around 3:50 – 4min/km (6:10 – 6:26min/mi), which is about a 39min 10km or 1:26min half marathon. If you cannot run a sub 40min 10km, you have next to no chance of running sub 3hrs.

Your sub-3hr target pace is 4:16min/km (6:52min/mi), which means your 1km/1mi splits will drift between 4:10 – 4:20min/km (6:42 – 6:58min/mi). Unless you’re running on a treadmill, you NEED to be capable of running 4:10min/km (6:42min/mi) without going over your threshold.

Suppose your threshold is slower than 4min/km (6:26min/mi). In that case, you will burn too much muscle carbohydrate, accumulate lactate/acidity, and subsequently build fatigue too quickly, which will have you hitting the wall before the race end.

There’s more than one threshold…

However, your lactate threshold is only one of the thresholds that matter. The other threshold is your aerobic threshold. Essentially, how efficient you are at your marathon pace. Your running economy at marathon pace comes down to your underlying aerobic fitness and conditioning. If you’ve never run over 20km, your muscles will lack conditioning to exert force for 3hrs, and you’ll end up breaking down after 2hrs, regardless of whether you can run a sub-40min 10km or not.

Therefore, you’ll need to be able to run 20km at marathon pace without your heart rate going above zone 3 or higher than 95% LTHR, which I would consider a steady state. I.e. Energetic supply and demand are sustainable.


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So, what about training? How much, how far, how hard, who, what, when, where?

I think it was Jack Daniels who answered the question “How much training should I do?” with “As little as you can to get your desired outcome.”

I like that answer because throughout my coaching career, I’ve seen people roll out of bed and run sub-40min 10km, and I’ve seen dedicated runners struggle to break the 20min for 5km after years of training.


I believe two weekly workouts would get any runner under the wholely 3hr barrier should they have the capacity.

  1. Threshold intervals of 5 – 15min – Zone 4/5
  2. Marathon tempo running of 10km+ – Zone 3

Outside of these two workouts, all a runner needs to do is easy-aerobic running. How much? As much as you can handle without affecting the quality of your two key workouts (or getting injured or sick).

Tell me more about these magical workouts.

As I’ve said, running a sub-3hr marathon (or any marathon time) relies on two thresholds. Your aerobic (with oxygen) and your anaerobic (without oxygen) thresholds. The higher you can get each of those thresholds, the more sustainable marathon pace becomes. Therefore, we need to work those thresholds consistently to stimulate and adapt the desired metabolic pathways.

Threshold Intervals

How you skin that cat is dependent on your physiology. I’d typically target 30min with threshold “work” within the workout. I recommend starting conservatively, aiming for 5min or one-mile repeats in Zone 4 (95 – 100%) with 2min recovery. You can build from there. The goal isn’t to over-exert yourself. Instead, you’re massaging the targeted metabolic pathways to stimulate progression. If you go out and try to turn yourself inside-out on every interval, you’ll miss the workout’s physiological goal.

Marathon Tempo

The cornerstone of specificity is running at your goal pace. The aim is to build the amount of time you run at marathon pace while maintaining a metabolic steady state. I see these workouts as being built from the bottom-up or top-down.


You start with 10km at marathon pace in week one and progress from there, adding a few more Km each week.


You add 5km of marathon pace running to the end of your long run. You progress by increasing the distance/duration of the marathon pace segment while reducing the distance/duration of the easy-aerobic running that comes before the marathon effort.

Either way, you should end up with 25-30k of marathon pace running as your final progression.

These are reasonably basic workouts, and how you skin this cat will depend on your training profile and individual physiology.

What about weekly Kms/Miles?

Who cares. In my first podcast episode, “Why pro runners don’t care about their weekly mileage (and neither should you)”, I outlined why pro runners don’t care about weekly mileage. The formula I’ve outlined here can be done in as little as 60km/wk or as much as 160km/wk. Your training works if you’re completing your quality workouts and seeing progression towards your desired outcome.

How to run a sub 3hr marathon key takeaways;

  1. You need a lactate threshold of 3:50 – 4min/km (6:10 – 6:26min/mi), which is around a 39min 10km or 1:26min half marathon.
  2. You need to be able to run 20km at marathon pace without exiting a steady-state (Heart rate zone 4)
  3. You need two weekly workouts; threshold intervals and marathon tempo runs.
  4. Quality over quantity. There is no magic number. Focus on your performance within your workouts, not your Strava.

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All workouts are locked and loaded. I outline a step-by-step approach for how you can test your threshold, set your zones, and use your data for effective, accountable, confidence-building training. Best of all, my workouts automatically adjust to your threshold and download your watch, so you’re always running at the right intensity.

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2 comments on “What it takes to Run a sub-3hr Marathon | The Numbers AND The Workouts”

  1. July 14, 2024 at 2:03 pm

    This is an interesting blog post. I have never run a marathon, but I have run a few half marathons and I can tell you that it is definitely a lot of work. I think it would be really hard to run a

  2. July 14, 2024 at 5:29 pm

    This is an interesting blog post. I have never run a marathon, but I have run a few half marathons and I can tell you that it is definitely a lot of work. I think it would be really hard to run a

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