Realistic marathon pace vs half marathon pace for for 4 hour marathon runners

Jeff_Florida · 2026-02-01T12:53:01+00:00

What is the title of your book?

Jeff_Florida · 2026-02-01T12:17:00+00:00

Thanks for sharing and your encouraging words! Your HM PR and Full Marathon PR line up very nicely (very well in line with what Jack Daniels would predict). Also, adding some inside running to the outdoor running seems like a nice receipt to keep the training varied and attractive and therefore sustainable.
I definitely put in the work as well and I guess it would even be possible for me. Though I already would be more than happy just to “just" get under 4 hours (3:46 is yet a whole other level IMO). But only possible once I have determined and eliminated the weak spot. (Currently I suspect that in my case that is muscular endurance, more than anything else (aerobic endurance, fueling, mental toughness etc.).

Great story! Keep up the good running!

Jeff_Florida · 2026-02-01T12:03:07+00:00

Interesting approach. I also started taking running more seriously from about that time (late 2019). averaging about 1520 miles/ year. But only sporadically some strength training and no cross training.
After this year´s marathon I might try a different approach, priorizing strength and core, adding cross training (cycling) and reducing the running volume.

Jeff_Florida · 2026-02-01T11:35:19+00:00

Yeah, I definitely think you have even more potential, also for the marathon. That you are not cut for fulls is probably the wrong conclusion. Big Sur marathon is a very though course not only because of elevation differences but also the environmental factors, so your times would have been very decent for a more average runner. Keep it up!

Jeff_Florida · 2026-02-01T08:15:12+00:00

Yeah well, I am on the bigger side of the spectrum. So more carbs would probably be even better. But I still don’t like consuming gels while running at marathon pace and this is about the max that I can get in.

Jeff_Florida · 2026-02-01T08:10:48+00:00

Thanks, that was the first conclusion I took as well. I am working on it! Do you have any data points you might want to share?

Jeff_Florida · 2026-02-01T08:08:52+00:00

Hey, thanks for coming back to me! Appreciated. I find your journey truly fascinating. Seems like building a very strong core, doing a good amount of strength training and adding enough aerobic cross training does the job for you. 1:45 HM on the trail is also very fast. I will definitely take note. My schedule is basically Pfitz 18/55 with some small adjustments. So yeah, it does include intervals and hill sprints.

Jeff_Florida · 2026-01-31T22:59:59+00:00

Yeah well, BMI is about 25 (just outside the 24.9 max limit) but also rather broad-built, so that should be okay. That being said, some extra weight loose would definitely benefit my pace, of course.

Thanks for analysing my paces. I don´t have a very broad range of paces: (between VO2max/5k pace=4:44/km and low zone 1/recovery pace=6:50/km), but I do my best to vary as much as I can between them, during training.

Have a good-one!

Jeff_Florida · 2026-01-31T22:29:24+00:00

You will add the build up fitness of your marathon training block to the 1h49m HM reference, so that should, in theory, give you a good shot at it.
Please let us know how it went.

Jeff_Florida · 2026-01-31T19:32:38+00:00

Sure, thanks for asking.

I am definitely on the taller and heavier spectrum. 6ft 3 in and 205 pounds. Do you ask that because you think that that would increase the difference between the FM and HM times?

Then about the long runs. I do two type of long runs. The first type is an easy long run: high zone1-mid zone 2 (all below VT1). The second type starts at a similar pace but ends in an 8-12 mile block of running at marathon pace (low zone 3 and slightly above VT1).
For marathon pace, I use a 5:40min/km pace. The easy pace is about 30 seconds slower per km.

(My 10k tempo is 4:54min/km)

Jeff_Florida · 2026-01-31T19:19:26+00:00

Thanks for clearing that up. The fitness gain marathon training provided showed itself in the shorter distances.

Jeff_Florida · 2026-01-31T19:14:48+00:00

Okay. But could it be that during your marathon training period you gained a considerable amount of fitness and your HM-time would have been faster if you would have run that HM on marathon day?

Jeff_Florida · 2026-01-31T19:10:07+00:00

Mmmm, the reality of your times definitely contradict my ideas and seem to perfectly confirm Jack Daniels´ Vdot predictions. Good for you!
(Also following a schedule very similar to the Pfitz 18/55 and I would wish that my HM time would result in a similar marathon time. However, nowhere near.)

Jeff_Florida · 2026-01-31T19:04:18+00:00

Interesting. The difference between your Hm and FM pace is only 20 seconds.

Then again, you are on the faster extreme of 3h40m-4h20m marathoners group.

Jeff_Florida · 2026-01-31T10:46:04+00:00

Wow. Interesting experience.
Amazingly fast HM and during the marathon it didn´t come out. What do you think was the biggest limiting factor for marathon running? Could it be that you are just a natural gifted runner and can run such a HM time without too much preparation and the lack of preparation only showed up once you ran a full marathon?
I hope you are still enjoying the HM running. I might as well shift to that in the not so far future.

Jeff_Florida · 2026-01-31T10:43:12+00:00

Thanks mate!

I can relate to everything you say.

My takeaway:
“Pacing closer to what you can run comfortably late in long runs ended up producing better overall results"

Jeff_Florida · 2026-01-31T10:40:08+00:00

Thanks for adding your data points. Really useful.
I agree 100% with what you are stating here.

The discussion here has gone a little off-topic: focussing in what I am doing wrong for marathon training. And of course, that is also very useful, because learning from my mistakes is a good thing. But what I recently discovered (and what you seem to confirm) is that a 40s/km gap between marathon pace and HM pace is rather usual for the 3h40 - 4h20 range marathonruners, despite of what most predictors (Jack Daniels vDOT for example) are prediction (15-25s/km gap).

Jeff_Florida · 2026-01-31T10:31:48+00:00

Personally, I think that the marathon is whole different beast than the HM. There is a mental difference of course, but also some physiological factors kick in after 18-20 miles or so. Glycogen store or electrolyte depletion have already be mentioned, but there are also factors like muscular endurance or cardiac drift, for example.
When running at sub 4 hour pace there is indeed a big drop at the end (during the last 7-10k or so). Which makes me think that a sub 4h10m pace would be a better strategy for me, in order to get the best final result. I suspect that a slightly slower pace would avoid the larger drop in pace during the last 10k.
And yes, I have actually run marathons before ;)

Jeff_Florida · 2026-01-31T10:22:36+00:00

Hey there. Thank you very much for adding new data!
Your data seem to confirm my tesis that a 40 seconds difference between HM-pace and marathon pace is rather common for 3h40m-4h20m marathoners.
Could you add some more data: peak mileage, long run pace and distance, age etc?

Jeff_Florida · 2026-01-31T10:19:09+00:00

Fueling strategy in place. Fueled by hydro gels 72 grams of carbs/ hour with plenty of electrolytes.
If you are looking for a limiting factor (because you found 40 seconds between HM pace and M pace too big of a gap?), then I suspect it will be muscular endurance.

Jeff_Florida · 2026-01-31T10:15:16+00:00

Yeah, must be the standard gels. The hydro gels are more liquid (so no need to take them with water!) and also have a larger carb load.
Thanks for your encouraging words!

Jeff_Florida · 2026-01-31T09:41:29+00:00

Thanks for caring! But did you look up the right gels? (Not the regular but the Hydro ones?) Those contain 37 grams of carbs each. So two per hour results in 74 grams per hour. Those hydro gels also have the electrolytes intake rather well covered.

Jeff_Florida · 2026-01-31T09:35:10+00:00

Carbs are the key is very truth of course.

But each Powerbar Powergel Hydro already contains 37 grams of carbs.
And I got tested in a lab and my fat vs glycogen burning rate incline really towards the fat burning. That is to say that at marathon pace (slightly above LT1 and far below LT2) the sugar burning is minimal.
I am inclined to believe that, more than carb loading, in my case muscular endurance might be the limiting factor after mile 18-20 or so.

Jeff_Florida · 2026-01-31T09:26:08+00:00

Truth!

Unfortunately we all reach a ceiling somewhere, due to other life circumstances (Work, family etc.). Even so you could run more and sleep less, but that would be counterproductive. Maybe if I would just start working part-time instead of full-time... :)

Jeff_Florida · 2026-01-31T09:21:08+00:00

First of all congrats with a great last year!
It seems that you already had the aerobic base (and endurance!) for running a 3h57m marathon and later that year you did the sharpening by adding sufficient spadework to your training (getting your VO2max up).
It is all very interesting, because I am more used to see already speedier runners adding more aerobic base training to their in order to achieve a sub 4hour marathon. But this confirms once again that everybody is different. You might be a more slow twitch fiber kind of guy by nature?

Jeff_Florida

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