Should You Include 20 Mile Long Runs in Marathon Training?

Should You Include 20 Mile Long Runs in Marathon Training?

20 mile long runs appear as much of a staple on many marathon training plans. During the past few years, however, many popular methodologies including the Hansons Marathon Method have proclaimed 20 mile long runs as unnecessary. Many runners will soon begin training for summer and fall marathons, so let’s look at the advantages, drawbacks, and considerations of the 20 mile long run.

Of course, this post will only skim the surface of this debate. Research on the physiology of long runs literally fills volumes. As always, please consult your running coach before making changes to your training plan. Don’t have a coach? Learn more about my coaching services!

Should You Include 20 Mile Long Runs in Marathon Training?

Pro 20 Mile Long Runs

Some coaches, including the coach who taught my RRCA seminar and Brad Hudson of Run Faster from the 5K to Marathon advocate that experienced marathoners (NOT new marathoners) extend their long run to last nearly as long as their goal time in order to adapt to that duration of time on their feet. Obviously, these runs are executed at a significantly slower pace than marathon goal pace; a 3:30 marathoner will run for 3 hour and 30 minutes but only cover 22-23 miles. These long runs will teach your body to handle all of the physical demands of the marathon while also mentally strengthening you for your race.

20 mile long runs, for many runners, break a mental barrier. If you can run 20 miles, you can run 26.2! The 20 mile long run has become a staple in most marathon training plans, regardless of overall weekly mileage or training paces. It’s the hallmark of marathon training, the run which many runners consider their peak workout.

Anti 20 Mile Long Runs

The most famous of the no 20 miler marathon training plans is the Hansons Marathon Method. The Hansons Marathon Method (which regular readers will recall I followed for the Portland Marathon last year) advocates a 16 miler cap for their long runs for their standardized training plans.

Hansons cuts all long runs off at 25-30% of total weekly mileage. So if you’re running 60 miles per week (which is high mileage for many recreational runners), 16-18 miles falls within this range. Luke Humphrey, author of Hansons Marathon Method, cites too many high risks as the reason for not running more than 25-30% of your total weekly mileage in a single long run.

“Breaking this cardinal rule risks too much: injury, overtraining, depleted muscle glycogen, and subpar workouts in the following days or even weeks.”

If you’re following the Hansons Marathon Method but increasing your weekly mileage (primarily through extending your easy runs and warm up/cool down miles), you may be able to include 20 mile long runs while still adhering to their guidelines. For most recreational runners, generally speaking, weekly mileage over 70 miles is neither recommended (diminishing returns) nor feasible in the balance of family, work, and running, which means most will not hit the 20 mile point following Hansons plan.

The science behind this limit on the long run is not unique to Hansons. The renowned exercise physiologist Jack Daniels argues the optimal duration of a long run is 90 minutes to 3 hours, which may or may not include 20 mile long runs. In his book Jack Daniel’s Running Formula, he writes:

I like to limit any single run to 30 percent of weekly mileage for runners who are totaling fewer than 40 miles per week. For those who are accumulating 40 or more miles per week, I suggest [long] runs be the lesser of 25 percent of weekly mileage or 150 minutes, whichever comes first.”

Numerous studies and coaches agree that after 3 hours, you reach the point of diminishing returns. The most physiological gains are made in 1.5 to 2.5 hours of running; once you surpass three hours, you cease to reap any additional physiological benefits and sharply increase your risk of injury.

Individual Considerations

Yes, a 16 mile long run will sufficiently build your aerobic capacity for the marathon, so long as you are following the other pillars of the Hansons Method: overall high mileage, back to back longer runs, long marathon paced workouts, and cumulative fatigue.

However, as many of us know from experience, there is more to racing the marathon than simply building adequate endurance. Your legs and lungs are not solely responsible for carrying you over 26.2 miles; your stomach, mind, and feet must cooperate as well, especially if you have a goal time in mind.

For example, when I followed Hansons Marathon Method, I completed my 16 mile long runs in under 2:20. These long runs certainly prepared me to cover 26.2 miles, but I was not completely mentally prepared nor was my sensitive stomach trained to handle the pounding of running for well over 3 hours. At my training pace, I could still run 20 miles in training and finish in under 3 hours.

Your pace and race goals factor significantly into the length of your longest marathon training run. The general consensus appears to be that time, not distance, should be the deciding factor in marathon training long runs. 3 hours should serve as the cap, since that’s the point before you incur diminishing returns. Let’s keep in mind that a majority of long runs should be done at your easy pace, which for most runners is 50 seconds to 2 minutes per mile slower than goal marathon pace. 

So let’s say you are aiming to run a 4 hour marathon (9:09/mile average), which is a popular goal for many marathoners. Your long run pace is approximately 10:00/mile or slower; running at this pace for 3 hours will cover 18 miles. 18 miles is thus an adviseable cut off for marathon long runs for the 4 hour marathoner, while a 3:30 marathoner can cover 20 miles in 3 hours during training, and a 3 hour marathoner could extend up to 22 miles without incurring detrimental levels of fatigue.

Finally, there’s the issue of quantity: Arthur Lydiard, the great master of long slow distance training, asserted that athletes only needed one 3-hour long run 5-6 weeks before their marathon to reap the benefits. (It is worthwhile to note, however, that many of Lydiard’s athletes were highly skilled distance runners and able to cover the marathon distance or further on a 3 hour run).

On the flip side, an argument can be made for including 2-4 20 milers in your training, particularly if you can complete an easy 20 miler in under 3 hours (so, typically for 3:30 marathoners and faster). You prepare your body for the demands of the distance while also training your mind to handle the mental demands of the marathon distance.

Portland Marathon Race Recap 2015

Marathon Specificity

Here’s one final question to consider: what will better prepare you for the marathon, easy 20 mile long runs or a 14-18 mile long run with a large portion at marathon goal pace?

The answer to this question is as individual as each runner. However, specificity is one of the key factors in race training. The more specifically you train for your goal race, the better you can expect to run on race day. Shorter yet hard long runs offer numerous benefits, including improved fat burning and running economy at goal marathon pace, training your body to run at goal marathon pace for a sustained period of time, and adding variety to the weekly long slow distance run.

Runner’s Connect even recommends that marathoners running slower than a 3:30 marathon favor shorter and faster long runs over 20 mile long runs, for the sake of reducing training fatigue and preventing injury.

I would argue there are benefits from both easy 3 hour long runs and from marathon-paced 2 hour long runs (so long as you have the overall weekly mileage and training background to support these workouts). Furthermore, including both in training (with cutback weeks) will stimulate various physiological adaptations while keeping marathon training boredom at bay.

Too many hard long runs will burn you out before race day, while only easy long runs prepares you, well, to run long at that easy pace. For new marathoners, all of your long runs should be performed at an easy pace to adapt your body to the new distances without overtraining or injury. Endurance first, then speed.


Ultimately, the inclusion of 20 mile long runs hinges upon a wide variety of individual factors: injury history, recovery rate, pace and goal time, your experience in marathoning, and your overall weekly mileage. As Pete Pfitzinger says in his book Advanced Marathoning, “No scientific evidence will tell you the best distance for you long runs as you train.” It’s something you have to decide for yourself by taking all of the factors into consideration and weighing the risks and rewards.

Runners of any ability will reduce their risk of injury and prepare themselves better for the marathon by following the 3 hour cut off for marathon training long runs and by safely increasing their weekly mileage so their long run is not 40% or 50% of their total weekly mileage.

As I’ve said before, cookie cutter training plans do not address your specific needs as a runner and therefore do not always optimally prepare you for a race. A good self-assessment or, even better, working with a certified running coach will guide you in planning out your marathon training plan.

Linking up for Coaches’ Corner and Wild Workout Wednesday!

Do you run your long runs by distance or time?
How long is your longest run before a marathon?
What other aspects of training do you need to consider (like mental strength, gut, etc)?



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30 Responses

  1. For my first marathon, I did 3 20 milers, and I really think it helped prepare me for the race. I knew I could do 26 miles because I had done 20 so many times! Since then I think I have stuck to 2 20 milers, except when I followed Hansons. I do like getting in at least one 20 miler, just to help me “practice” running for a long time before race day.

    1. 2 20 milers sounds like a good balance – enough to get the distance in, but enough to also allow long run workouts and recovery 🙂 I do think you’re right – it’s good to practice being on your feet and running for that long, especially getting the stomach and the brain used to it. And the feet! I remember my feet hurting during those later miles of my marathon because they just weren’t used to the pounding.

  2. I have yet to run a marathon but I would absolutely want to run 20 miles before the race! I would need that mentally and physically before running 26.2. I usually run my long runs based on miles but sometimes then look at the time to round things up. I don’t think I have ever run longer than 2:20 so I should consider trying for longer one day! I know I can do it, I just never feel the need. maybe if I ever run the marathon.

    1. I definitely think it’s mentally important! I remember before the Portland Marathon just not knowing what to expect in those later miles because 16 miles wasn’t much further than I had done in half marathon training but a marathon is so much further than a half (obviously). Long runs are very much based on need – especially when you can get many of the same physical benefits from a 2 hour long run as a 2:30 long run. But I’ve also heard advanced runners say extending long runs to 16 miles helps so much for the half!

  3. I am a fan of the 20 miler for a few reasons, and I believe that, if it is done correctly, it can be hugely beneficial come race day. I think it is a great tool for building confidence in first time marathoners, and proper coaching can help minimize issues and problems that might arise from it. However, I do understand that there is now an influx of runners who take much longer to run marathons (which is great!! GET IT PEOPLE), and so spending that much time on your feet prior to the marathon might not be a good idea. I say, as with all coaching, it is a case by case basis.

    1. Done correctly is the key here, yes! Coaching is so important for minimizing any issues with the 20 miler, especially for new runners. It can increase risk of injury, but it doesn’t mean it WILL or HAS TO cause injury.

  4. This is definitely helpful as I mentally prepare to train for my first marathon. I hope to hire a coach as the race approaches but it was interesting to read the different opinions regarding the 20-miler! I see myself as wanting to do at least one in my training, mostly for the mental aspect of it.

    1. When’s your first marathon? How exciting!! The first marathon is such an empowering and exciting experience.
      A coach will definitely be helpful for that, since marathons are so tricky to navigate for even experienced runners and a coach can remove all of the guess work and adjust everything as you progress. If you are looking for a coach I’d love to work with you – I offer both personalized plans and will be launching a marathon training camp to have coaching + group support this summer for fall marathons!

  5. I only ran one marathon, and I hesitate to say I “trained” for it, but if I run another I will probably do the opposite of what I did. My emphasis was on the long runs, which were long and slow. Aside from that, I was doing my easy days at faster than marathon pace (which I now know is a big no-no, but I was only running 4 days a week and recovered so well that I *felt* like I was running easy when I wasn’t).

    My marathon was more like a death march, and I think there’s a big advantage to running some longer miles at marathon pace, as a part of a long run or tempo. I didn’t know how that pace felt on race day and went out too fast and crashed and burned.

    I like the Hansons plan for the half and used it with great results. I wouldn’t trust myself to run a marathon with a long run of 16 (yeah, I would deviate from the plan there!). People who haven’t read the book seem to think their plans are easier just because the long run tops out at 16. Never mind that the mileage on the other days and workouts are longer than other plans. I think with a Hansons plan you would end up running more mpw than the others even with the shorter long run.

    1. Yes I’m a huge advocate of adding “stuff” to long runs for runners with the appropriate base, especially if they’re training for a half or full marathon. It’s important to know what race pace will feel like for several miles! Hansons really is so much more than people give it credit for, because you have two hard workouts, a medium run before your long run, and that long run is at a moderate pace – plus 60 mile weeks are no joke. I’d rather see new marathoners focus on overall mileage and 3 hour long runs than add in harder stuff – endurance then speed.

  6. #Team20Miler! I think it works for me because I am at that sweet spot where, at my training pace, a 20 mile long runs takes me just a few minutes over 3 hours. It is the only long run in which I hit and exceed the three hour mark so that’s why I include at least one of them in training (I have 2 this cycle). I don’t do anything longer than 20, though. Many of my friends do 21-23 mile long runs; I did one 22 miler for my first and now I don’t really see the point – I’m not fast enough to get any additional benefit from adding those extra 2 miles. As I get more marathon training cycles under my belt I’m also moving farther away from the “every long run has to be super slow” philosophy. Every other week I try to incorporate some race pace practice into my long runs, or hill repeats, or race a half marathon.

    I have been tempted to cap at 18, but I have to confess that temptation is driven by sheer laziness. I hate long runs. And yet I love running marathons. Go figure!

    1. There really isn’t much point to going beyond 20, unless you’re super fast (like, 3 hour marathoner) and can fit them in at that mark – otherwise it’s diminishing returns. Not that there’s anything wrong with it unless they’re getting injured, but just not much difference even mentally – exactly like you said. And yessss add in those MP miles into your long runs! or fartleks or tempo miles! Girl you are going to crush it at PGH if you’re adding hills in to long runs!
      And I think every distance runner has a bit of love/hate with long runs. Love them in the race, love them at the end, sort of hate them before and during those first 5-7 miles.

  7. As I think about choosing a training plan for my first marathon (NYC in November) this is something I am really struggling with. Ideally I want to run a 4:30 marathon, my recent half PR being 2:06, so for me the cutoff seems to be 18 miles – yet I’ve heard from others that you “need” a 20 or even 22-miler not to bonk at that point in the actual marathon! I’ll be really interested in your training plans for fall marathoners.

    1. 18 miles/3 hours will build your fitness and get you used to the time on your feet (3 hours is quite a long time to run!). Bonking comes down to getting your body used to marathon pace as well as running for 3 hours, really zoning in on nutrition (both during your runs and throughout all of training, making sure those glycogen stores are replenished), and pacing right. It’s takes careful planning and attention to a lot of factors but it is definitely possible to not bonk off of a 3 hour long runs. It’s something I will work with in my fall marathon training camp, which should start in May and sign up should open in late April-ish! I’ll share more once I finalize everything 🙂 I’m excited that you’re interested!!!

  8. I love what Susie said. I’ll add that in my own experience over the years, there is something magical about the 20 mile distance. BUT. Like you said, it’s such an individual thing. As a 3-3:30 marathoner, I wouldn’t be out there for hours like a 4:30-5 hour marathoner would be.

    I’m learning just how individual each person really is when it comes to running. I think I’m finally finding the right balance of training that works best for Andrew, but it took a while!


    1. Thank you! Most runners do find that the 20 miler is magical – and that mental training is! It is very different as a marathon finishing the the 3 hour range than one finishing in 4 hours or more. It’s so individual with pacing, not to mention recovery rates! It sounds like you’re doing so well training Andrew and I’m excited for both of you!

  9. I find this debate so fascinating! I agree with so many of the points made, especially about running for time and not necessarily mileage. I do think, as you said, it all comes down to the individual runner. The marathon is such a beast and I still didn’t have my training figured out after running 7 of them! I will say this – no matter how long you run your long run, you will discover so much about yourself in the process!
    Really great article Laura.

    1. Thank you Allie!! The marathon is SUCH a beast – sometimes it scares the s&%$ out of me because I feel like as a coach I should figure it out more, but you’re so right – no matter how many you run or how much you read, there’s still so much to learn – both about running and yourself.

  10. I trained for a March marathon (would have been my first, but I didn’t get to run it because migraines control my life!) and did a 20 miler and a 23 mile run in my training. I needed those runs for the confidence. So much of my running is mental and I lose a lot of energy to stress leading up to the big day, without those runs I could psyche myself out too easily. Plus, after that 23 miles I was so sore and ready to be done, I couldn’t have made it another 3.2.
    I do often run my long runs by time as well, like that 23 mile run was supposed to be 24 or 4 hours, whichever came first. When I’m not training for a marathon or half, all of my long runs are by time and I just run easy.

    1. Oh, that’s unfortunate that you had to miss your marathon after training so hard! 23 miles during training is tough with the soreness, not to mention how that long would drain glycogen stores too much before a race. 20 miles is great for building confidence, as are shorter long runs done with miles at goal pace – those really prepare you for the race!

  11. I see the benefits to both. In the past, I’ve always capped my marathon training long runs at either 20 or 18 miles. For my next marathon, I want to go for time, so I’m planning on surpassing the 20 mile mark to really work on my pacing through those later miles.

    1. The marathon takes a lot of experimentation to find what type of long runs work for each individual! There is definitely something to be said about working on pacing, which is why I love the idea of both the 18-20 mile long runs and shorter 14-17 mile long runs with MP segments.

  12. I have seen this topic up for debate SO MUCH lately. It’s come up in almost every Facebook group I’m in and it’s usually new marathoners. Very thorough, thanks for linking up!

    1. It’s been all over Women’s Running I’ve noticed as well! As Hansons gains in popularity I think many runners are asking the question! Thank you for hosting 🙂

  13. Great post. It really needs to be so individualized. Another reason why a runner needs a coach, so that the coach can analyze the situation and create the proper plan for that individual runner.

    As a runner myself, I always ran a couple of long runs of 22-24 miles. I found that my exercise induced asthma improved, I assume as my lungs adapted to the longer distance. I once ran 27 miles in preparation (not that I would recommend that for most runners).

    I also included shorter long runs (if that makes sense) usually during a cutback week, of up to around 14-16 miles, which were partly done at marathon pace or even slightly faster.

    1. Thank you – and thanks for hosting! The marathon long runs is such an individual situation, as you show – what works for you is different than what you’d recommend to runners. I really think those shorter long runs at a faster pace help so much! It’s beneficial for most runners to get used to running for extended periods at marathon pace.

  14. I love that you address that there is no ‘one size fits all.’ When I trained for marathons, I felt like getting the distance in was really crucial for me. My body can’t handle TONS of speed work, but it did need the distance.

    1. Thank you! Different runners handle distance versus speed so differently, and so many training plans neglect to think about that! I really believe there’s not a one size fits all plan, especially when it comes to a distance as inherently challenging as the marathon.

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