17 Miles! (And Some Interesting Science About Long Runs)

On Saturday I did the unthinkable and got up at 4:15am to get ready for a MORNING long run. I am so not cut out to be an early riser.


My pace was a good 15 seconds slower than normal for the first 7-ish miles because my body was in total shock that it wasn’t just dreaming that I was running.


But guess what???? I MADE IT 17 MILES!

And guess what else???? It was way easier than when I did 16 miles and had a crappy finish!

My legs were definitely sore by the end, but thanks to eating more chomps than usual I finished with energy still left in the tank.

On Thursday I was talking to my coach about the rest of my marathon training plan. We started talking about what the longest run I would do will be.

My coach mentioned that I could top out at just 18-miles for a long run, though I said I would prefer 20 miles. Why only 18? As it turns out, any long run over 2.5 hours provides more mental training than any physical benefit.

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Research has shown that your body doesn’t see a significant increase in aerobic development, specifically mitochondial development, when running over 90 minutes. The majority of physiological stimulus of long runs occurs between the 60 and 90 minute mark. That means after running for 3 hours, aerobic benefits aren’t markedly better than when you run for only 2 hours.” (Competitor)

If this is true, why do most people run 20 and 22-milers as part of marathon training?

“The foundation of marathon training still comes from the 1970s and 1980s at the beginning of the running boom. Marathoning hadn’t quite hit the numbers it has today, and the average finishing time at most races was closer to 3 hours. As such the basis for how to train for a marathon came from runners who averaged close to 6 minutes per mile for the entire race. Therefore, 20 and 22 milers were common for these athletes as a run of this distance would only take them about 2.5 hours to finish at an easy pace.” (Competitor)

According to Marathon Nation and multiple other sources, this is why splitting up a long run (or simply not running more than 2.5 hours) during marathon training can be beneficial for slower runners.

Most of the things that I read seem to suggest that it’s better to focus on shorter runs during the week that work to increase your aerobic base rather than focusing on running for many hours just to reach the proverbial 22-miler.

Basically, focusing on shorter, high-intensity runs during the week will help a runner get faster and also allow a runner to train on fatigued legs more often which simulates the late-race feeling. This helps the runner build up mental strength when it comes to fighting off the “I’m sore, I just want to stop” feeling.

I thought all that research was really fascinating! (Although I still intend to run a 20-miler).

Cheryl has been using split runs for the marathon training cycle she is in now, and I will be so interested to see what she thinks about it after running her marathon. (She’s not doing it because she is a slower runner, but rather for other benefits).

I’ll definitely be keeping this split idea in mind for when I start 50K training. I had noticed that a few elite ultrarunners do two-a-days in training and I assumed that it was just because they like running so much, but maybe it’s for similar reasons.

It makes sense that running on fatigued legs from the morning would benefit them for the later stages in an ultra race, especially if simply running longer in the morning isn’t providing them additional aerobic benefit.

Have you ever split up a long run? 

What is the longest you like to run during marathon training?



  1. August 18, 2014 / 7:37 am

    Way to go on 17!!! Hmmm that is really interesting research. I know this week’s long run (15-16 miles) will provide me with a mental boost – since I have not run that distance (straight) since 2007.

    • August 18, 2014 / 8:01 pm

      Thank you! I’m with you, running long provides a necessary mental boost. I really think running a marathon is probably 60% mental and only 40% physical. As long as you’re not injured you can definitely keep going even when your legs get tired as long as your mind is strong and focused!

  2. August 18, 2014 / 7:41 am

    Running 20 miles might not be physically better according to the research, but damn does it help mentally. There is something about reaching the 20’s that helps on race day. Glad to hear your 17 miles went so well. 4:15 is officially way too early though!

    • August 18, 2014 / 8:02 pm

      Haha, YES 4:15 is crazy but I wanted to give myself an hour to wake up, eat and digest a bit. Plus at 5am it was already 85 degrees and 91% humidity!

  3. August 18, 2014 / 9:22 am

    Hi Kristina! This is definitely interesting reading. I also recommend reading Hansons Marathon Method if you haven’t already. They take a similar approach – not emphasizing the long run as much and talk a lot about running on fatigued legs. Great job on 17!!

    • August 18, 2014 / 8:03 pm

      Hi Desiree! I will have to check that out. I read Sage Canaday’s book (he ran for Hansons) and talked a lot about running on tired legs… but I guess if you’re running 100+ miles a week that’s bound to happen 🙂

  4. August 18, 2014 / 9:26 am

    Wow! 4:15 is early–but I hear ya, I have to get up earlier for those long runs to eat a little, digest, then head out…
    It’s like you read my mind with your research…I was going to ask you what your longest run in the training cycle was. I was thinking about bumping my longest (also 20) up to 22, but now I know it’s not necessary. I do believe I need to get up to 20 because it is a mental barrier. I haven’t decided if I will do it once or twice, I guess it will depend on how it goes…
    I am realizing while “in the thick” of training, how much of it is mental. (I wish I could find the confidence switch in my brain!)
    I think it is neat that you are a couple of weeks ahead of me in training–I feel like I am training with a partner 🙂
    Do you have a brand of gf bread that you like–I have tried a few duds…

    • August 18, 2014 / 8:04 pm

      I completely agree that running 20 will help with mental confidence on race day. I’m only going to do one 20-miler and it will be my last truly long run before the marathon. The rest of the remaining weeks I’ll be doing between 10-15 with fast finishes and/or higher mileage short runs throughout the week.

  5. August 18, 2014 / 9:45 am

    4:15am? Are you absolutely crazy??!!

    …and talented to be a morning rooster!

    • August 18, 2014 / 8:05 pm

      HAH! I am not a morning rooster at all. Saturday was an odd day for me. Most Saturdays I sleep in until 10 or 11 am 🙂

  6. August 18, 2014 / 9:54 am

    Hi there!! Awesome stuff!!! 17 miles – fantastic!! And early o’clock in the morning, what the…..?? 🙂 That is heaps interesting re: the long run science too. This is not a very scientific approach, but I like to fall back on my late father’s advice re: marathon training and ‘long run’ – if you can do half of the distance you’re training for easily, then on race day you’ll do fine, owing to the crowds, adrenalin, excitement etc….

    Also, WTF?! Just read your post below re: that nasty article. Surely it’s a joke article and not written by a runner?? Who thinks that way?!? Grrrrr…..

    Thanks for your email too! I reckon you should come on over and run the wall!!! 🙂 xxx

    • August 18, 2014 / 8:08 pm

      Hi Lou! 🙂 So good to hear from you! I hope all is going well for you, hubs and puppy and that you’re getting all settled in to your new home!

      I think your dad’s theory sounds about right. I know crowd support always adds an extra pep in my step!

  7. August 18, 2014 / 10:28 am

    Wow congrats on 17 miles! Way to go girl!! *high five*

    I have to be honest, I feel like we runners have information overload when it comes to all the advice, research, etc. It’s gotten to the point where I’ll read something that directly contradicts something else I read, even though both sources have science and research to back up their claims. I think we all just have to do what works best for us as individuals, and it takes some trial and error. There is no one-size-fits-all when it comes to training!

    I still plan to do a 22 miler as my longest run. Maybe I’m not getting the aerobic benefits from it, but that’s not really the point. As someone above me noted, it’s about mental preparation. It was a HUGE confidence booster when I finished my 20 miler a couple weeks ago. Now that I’ve done that, I know I can run a marathon. 🙂

    • August 18, 2014 / 8:11 pm

      I totally agree re: the mental preparation! I know having a run that starts with a 2 in the front will make me feel so much better on race day… even though the thought of still having to go another 10K after that can feel daunting at times.

      The information overload thing is so true. That’s definitely one of the reasons I like working with my coach. I just listen to her advice and block out the rest of the noise. I’m one of those people who, given enough time, will overthink everything so I just put my life in her hands, haha.

  8. August 18, 2014 / 11:26 am

    That is some very interesting information! Now, if I ever don’t feel like doing a 20 miler, I won’t feel bad about it??? hehe. I always do one 18 miler and one 20 miler during training. One time I did 21 miles but it was by total accident due to me not planning the route correctly. I always knew there was no point in training above 20 miles (just run the damn marathon!) but not training above 2.5 hours is quite interesting information that I will have to remember!

    • August 18, 2014 / 8:14 pm

      Nope, sorry Meg but you still have to run a 20-miler because you’re one of those super speedy runners who can probably finish it in 2:30! That’s the downside of being so awesome. Sorry about it! 🙂 🙂

  9. August 18, 2014 / 1:37 pm

    Congrats on your 17 miler! That was my long run this weekend too.

    I read that same article when I was working out my training plan for my fall marathon. Since this is my first marathon, I decided I wanted the confidence of already having covered 20 miles in training. I looked into Hanson’s, which tops out with a 16 mile run and has you running 6 days a week so that you are always running on tired legs. The training is supposed to be preparing you for the last 16 miles of your marathon. While it was an interesting concept, I decided it probably wasn’t the best choice for a first time marathoner.

    • August 18, 2014 / 8:17 pm

      I am with you on wanting the 20-miler just for the mental confidence.

      I run 6 days a week, but I was already doing that before I started marathon training. On Fridays I usually just run 2 or 3 miles though. 🙂

  10. August 18, 2014 / 3:29 pm

    Great job knocking out 17, and still having some gas in the tank is a huge confidence builder.

    I’m not exactly in marathon training per say but leading up to the marathon and eventually an ultra I plan to run 26 – 30 miles in a single run. But I will be watching you and Cheryl very closely lol

    • August 18, 2014 / 8:20 pm

      You are a really strong runner, so I don’t think you’ll have any problems if you want to do longer training runs. The rest of us have to worry about getting injured and/or having to take too many days off afterwards for recovery purposes 🙂

      For the 50K I definitely plan on running into the mid-20s, but I also plan on maintaining a high base after the marathon to assist with running a strong 50K. I haven’t decided yet what the base will be, but I think between 15-18 miles that way I just have to add on a few more miles when I start really training later this winter. That “keeping a good base” strategy worked well for me leading into the marathon. I do think I’ll try splitting up some of the long runs during that base building phase to test out how it works after Portland!

  11. August 18, 2014 / 4:36 pm

    Great job on the super early mooring and the 17 miles!!!
    Interesting research about the long run. Actually it makes me feel good about some of my current training for my next race!!!

    • August 18, 2014 / 8:21 pm

      When is your next race?? I don’t think you’ve really talked about a big goal race for the fall yet! Curious minds want to know 🙂

  12. August 18, 2014 / 6:33 pm

    Fantastic job on your 17 Miler!!! Thanks for sharing the interesting information about the long run! I would have never known! I always do a couple of 20 milers and a 19 miler in my marathon training. I think it’s more mental with me though. I like to feel mentally prepared to be out there that long running on my own will…lol. It does make me feel comfort knowing that I dont’ necessarily ‘have’ to do it though…hehe.

    • August 18, 2014 / 8:33 pm

      Heather!!! I hope to someday be a super rockin’, strong runner like you! As soon as I am I will be popping out 20-milers every weekend just because 😀

  13. August 18, 2014 / 6:34 pm

    That research is super interesting! I’m still going to run my 20-miler though just to know I can do it. It will make me feel more confident come race day! Congrats on an awesome 17-miler!!!

    • August 18, 2014 / 8:27 pm

      Thanks Courtney!!! I totally agree, the 20-miler will provide a huge mental boost heading into the taper!

  14. August 18, 2014 / 7:43 pm

    I was just talking to my chiropractor about this tonight! We agreed that 20 miles helps mentally more than anything….if you can run 20 miles you can easily run 6 more! But if you have quality workouts throughout the week you probably don’t need more than 16-18.

    • August 18, 2014 / 8:25 pm

      I hope it’s true that the 6 more comes easily :)! I am going to remember you said that in mile 24 and see what I think! haha

  15. August 20, 2014 / 10:40 am

    SEE Kristina!!! Those early morning runs are quite magical, aren’t they. 😉 Glad to hear that you made it through your FIRST 17 mile run and that you found it easier than your 16 mile run! I think it’s good that you are doing a couple long runs in the morning because that is what it will be like in Portland. That is some really interesting insight into the long run and different training programs. I personally always like to do at least one 21-22 mile run before a marathon, more for mental preparation more than anything. I also think it is important to finish the last mile or two during a long run at race pace.