What is harder? Marathon running or Marathon swimming?

I just did the Boston Light Swim today (8 miles) and had plenty of time for my mind to wander.
Here is a question that needs the perspective of many...

Is swimming a marathon harder or easier than running a marathon?
To keep the playing field as flat as possible, think of this in terms of equal duration of effort, so that means about a 6-8 mile swim vs a 26.2 mile run.

Here is my 2 cent answer: Very equal, but running is a bit easier.

My perspective is certainly influenced that in a previous life I was a very good marathoner, and now I am a good marathon swimmer. That may be the perspective of how everyone views this - that it depends entirely on what you are better at. If that's the case then I'd say they are about equal in difficulty.

Thanks for the input - Kiko



  • pavlicovpavlicov NYC USASenior Member
    edited August 2018

    I believe running is a bit easier, because the pavement/road does not move, wave or goes up and down as ocean does. It also does not try to drown me and one can stop and walk anytime. However, in my mind any sport that I can do in a horizontal position is a winner. I always tell myself that swimming is just like lying on the couch with some flaffing of my arms around.

    Congrats on the BLS. I heard it was challenging this year!

  • wendyv34wendyv34 Vashon, WASenior Member

    It depends on the person and how they are built. Many competent marathon runners would get too cold in conditions that we consider routine and they don't have the upper body strength (or technique) to swim for anywhere close to 3 hours. Marathon swimmers are frequently carrying extra bioprene for insulation, which would be a detriment to our chances at finishing a marathon run.

    I'd also say that a flat water lake swim might be comparable to running a marathon on city streets, but a cold, rough ocean swim would be more comparable to a trail run in the mountains, with wind, rain and the occasional hornet's nest.

    I have flat feet, which results in poor running mechanics. When I was running, (in my 20-mid 30s), the furthest I was able to run was 8 miles. Running was always painful. While swimming for 7 hours definitely results in some pain, it isn't crippling. For me swimming is much easier.


    It's always a bad hair day when you work at a pool.

  • swimmer25kswimmer25k Charter Member

    There's a very good reason why I am/was a swimmer. I'd rather swim a marathon than run one. The most I've ever run was 12 miles at my law enforcement academy, so I can't really be objective. However, look at the numbers of participants that run the NY Marathon every year compared to the numbers of the most well attended 10K by comparison. There isn't any. One of the largest US races is the Chesapeake Bay Bridge swim (only 4.4 miles), which draws 700+ swimmers (and most in wetsuits). It is still dwarfed by most marathon runs. Swimming is harder to train for with respect to finding time and places to swim, coaching, and overall access to events. I have several friends who've ran a marathon with a training plan downloaded off of the Internet. It's very difficult/impossible to be a successful swimmer following this paradigm. It takes so much more time to train as a swimmer than a runner. (I believe that the pounding runners endure is more than swimming and thereby more prone to injury. The only injury I ever had as a swimmer was a torn up shoulder that a quick scope fixed in no time). Talent and a lifetime of training is a huge bonus. It's hard to pick up swimming cold-turkey and be able to pull it off. Runners can stop and walk at anytime, or sit on a curb. Our only option when things go bad are to tread water, get out/quit, or drown. There's much less of a risk getting hit by a jet-ski as a runner.

    Before I got hurt, I specialized in races beyond 25K. The longer, colder, and crappier the swim the better I was. I like to compare these swims to some of the ultra-marathons that those nuts out there like to run. I'd still rather swim than run 100 miles any day.


  • BridgetBridget New York StateMember

    Apples and oranges. I've had many marathoners come to Stroke Tech to work on the swim portion of a triathlon and struggle to cross the 25 yard pool. They make the swim too hard. Once they slow down, they improve dramatically. I do a wacky form of locomotion on land- some run, some walk, and I like to use my small local mountain to do laps. 20 minutes up, 16 down usually. When I was doing triathlon, mainly Olympic distance, the run was the hardest part- and I rarely managed without walking. When the 2003 NYC Tri converted the 1.5K swim to a 5K run due to weather, it was grim. Daily total of 15K of running- most ever. Don't care to repeat it. ;)

    As to injuries- I have a history of back problems that have caused periodic pain and immobility since 1985, so I don't hammer a run. I boost my swim mileage over time to protect my shoulders and cross train with aqua aerobics to gain water supported range of motion. So far, so good, and I've gone pretty far. And I know that any distance I can run, I can swim farther. Cruising speed, not race pace.

    Ease of picking up and doing- sure, if we have useful feet, running is accessible. Gradually boosting intensity and endurance over time will help, as will attention to a full range of motion to strengthen lesser used but still supportive muscles. Land locomotion also boosts bone density, as does strength training. Options.
    For me, I gained access to a place to swim in the winter in December 2016-- first time i was able to do pool laps in over 10 years. Mainly, I'm a seasonal marathon swimmer- I get in the lake as soon as I can tolerate it and avoid the 50 minute drive to a pool. I am trying to relax about the winters off- I was very intense in mileage for summer 2017, but last winter was hard for me- swimming in the box was a major chore, and swimming is supposed to be a joy, not a punishment. I think that this winter will be more for local hiking and long walkabouts, and fewer weekly swims (gasp)- at least until I feel a better pool groove. I'll do en pointe ballet exercises to keep my "push off the wall" muscles ready for action.

    So, running vs. swimming? The question is less what is harder than what is more likely to bring joy.

    And as for picking up swimming later in life- I've taught many adult beginners who picked things up with no bad habits and did great. Never underestimate anyone. ;)

    As hard as I found the BLS yesterday due to cold, I would not want to have run 8 miles. :P Wasn't it GREAT???!

  • I agree with those who say "it depends." For me,.... I'd rather swim a marathon ANY day, than run one (and am still run-marathon training to "take revenge" on that distance). The kicker for me is how long it takes to recover. I recover WAY faster after a swim -- even a super long one -- than a run -- even a medium one.

  • IronMikeIronMike Northern VirginiaCharter Member

    Definitely based on the person. I just started to enjoy running when my knee decided to stop working right. Now, anything over a mile, hell, near a mile, blows my knee up something huge. Swimming never does that, so for me I'd rather swim for any length of time than run even a mile.

    As for the crux of your question, if I had to answer: I think running a marathon might be easier for a slow runner than swimming a marathon for a slow swimmer. So many marathon swims have course time limits (for good reason, yes, I understand that) that really push the limit for us slow swimmers. Meanwhile, how many friends of mine have completed their first, or second, or third marathon run in the 4:30 to 5:00 range. My daughter completed her first marathon (her first-ever organized run, actually!) in 5:55.

    If 10K swim is equivalent to a marathon run, as FINA says, then swimming is definitely harder than running due to these time limits. The one 10K I DNF'd (Swim for the Potomac 2012) had a 3:20 time limit. That's blazingly fast for normal mortal adult-onset swimmers such as myself. Admittedly, I can't be objective about this, this is just my $0.02.

    We're all just carbon, water, starlight, oxygen and dreams

  • gregocgregoc Charter Member

    A 10K OWS is considered equal to a marathon run based on time. An fast swimmer can complete a 10K in the same time it takes a fast runner to complete 26.2 miles. All other conditions being equal you would have to ask that fast runner and the fast swimmer how they feel after the respective events to answer the question.
    For me, I would definitely say running a marathon is harder. I ran the Boston Marathon in about 4:45 after training for a year. It took me a week to recover. I swam the Boston Light Swim twice. Once in 2:50 and once in 3:30 or so. I felt tired but good after each time. The BLS is an 8 mile swim, but it is more like a 10K with the tidal assist (usually).

  • dpm50dpm50 PA, U.S.Senior Member
    edited August 2018

    I've run marathons, and I've done three 8-mile marathon swims--one completed, two others DNF, but got to 6.5 in one, 7 in another. I've also done seven 5.4 mile swims (six finished, one DNF, which actually ended up w/ my swimming more than the race distance).

    After my first 5+ mile swim, it took over a week to feel normal. Now, I'm back to swim workouts within a couple days. After my first running marathon, same deal--took me a while to recover, but after my one Boston qualifier (1995), I recovered within a few days (I even wanted to run the next day, but the coach said not to).

    These days, running is definitely on the back burner, and every time I think of taking a run, I think "too hot--going to swim!" And when I do run, it feels so much harder than it used to. However, I was glad to have run a 5k in July 2 days after my 5.4 mile swim with no ill effect, didn't even hurt. But that was a 5k, not a marathon, and I wasn't running hard.

  • dpm50dpm50 PA, U.S.Senior Member

    pavlicov said:
    I always tell myself that swimming is just like lying on the couch with some flaffing of my arms around.

    LOL! Love it!

  • DuganaddyDuganaddy Needham, MAMember

    In part, I'm asking this because I get asked 'which is harder' a lot. Many people have some experience running, and even finding people who have run a marathon is pretty common, so the effort that running takes is a pretty well known quantity for many people, but swimming - especially longer distances - is pretty foreign to most. For the average Joe or Jane - swimming a marathon would be much harder I think. They don't have the technique, and learning that is not as simple as doing more miles for a running marathon where the 'technique' is somewhat natural and inside all of us to one extent or another.

  • SpacemanspiffSpacemanspiff Dallas, TexasSenior Member

    I agree that this is apples/oranges and there can't be a "right" answer, but if we go with the 10k swim as being the equivalent of a 26 mi run, I'm in the running is harder camp. Here's my rationale:

    (1) Like @pavlicov said, "swimming is like lying on the couch...." I often say something very similar to people: "swimming is the only endurance sport I know of that you can accomplish 100% of while laying down." On some level, I feel like most of my body is pretty relaxed when I swim. Sometimes, on really long swims, it almost feels like I could fall asleep if I closed my eyes. Running is the opposite: complete misery over every inch of my body 100% of the time (I felt like that even back when I was a 5x/week runner).

    (2) I could "wing" a 10K on any given day without any training beyond my usual 15k/week. Can a 51-year-old runner "wing" a marathon on 1-hour a day running? Perhaps, but it seems like that would be harder (not to mention the wear & tear on your body).

    (3) If a 10k swim is a marathon, then the running equivalent of a stage race like S.C.A.R. would be 40 miles, 40 miles, 66 miles, 26 miles. I don't have a lot of running knowledge, but that doesn't seem feasible for a 51-year-old runner.


    "Lights go out and I can't be saved
    Tides that I tried to swim against
    Have brought be down upon my knees
    Oh I beg, I beg and plead..."

  • MoCoMoCo Worcester, MASenior Member

    I'm not a great swimmer, but I'm a terrible runner. I've "run" 2 marathons (the second one was mostly walking due to a major attire failure and some pretty severe chafing). I've also swum two things over 10K and for me, they were mentally and physically easier than my running marathons. Not truly apples to apples because I did a much better job preparing for the swims, but still, add me to the list of those who would rather swim 5K than run it.

    OTOH, my husband is getting ready for ironman #6 this weekend, and I think he's also run about 9 or 10 open marathons (really, who can keep track). He bitches when he has to swim more than about 3200 at a time or two days in a row. For him, despite being faster than me in both sports, running is way easier because he finds swimming horribly boring.

  • dpm50dpm50 PA, U.S.Senior Member

    Another thought.... swim conditions can fluctuate widely. I'm planning to do the Spuyten Duyvil 10k, which I'm told is very strongly current assisted. Hard to compare to a similar distance that's current neutral or even partway against the current. Recently I did a 3 mile swim MUCH faster than I could do it in a pool. Couldn't take much credit b/c Mother Nature lent a major hand. In a run, sure you'll have some courses more challenging than others, but in mY experience, my times don't vary nearly as much. Even an 800m swim has taken me as little as ~20 minutes and as long as an hour depending on conditions.

  • BogdanZBogdanZ Bucharest, RomaniaSenior Member

    For me, i have done some of both, 10-15km swim is easier, even in training effort, than an 42k run.
    Excl.. elevation, currents, water temp, waves etc. Keeping both at "marathon pace".
    Probably because i am an ex swimmer and don't love running that much.

  • evmoevmo SydneyAdmin
    edited August 2018

    Given that I have never, will never do a marathon run, I cannot speak from experience.

    They are such different endeavors, and I admire those who can do both. A few years ago Darren Miller @ForeverSwim attempted a very interesting challenge - a sub-3 hour marathon run followed by a sub-3 10K swim, back-to-back. He didn't end up making the swim after a 2:58 run, but damn that would be a crazy impressive feat if someone pulled it off.


  • SamSam Member

    God I'd take a 10km swim over a 2km run anyday

  • FlowSwimmersFlowSwimmers Polson, MontanaMember

    According to google, in the US alone, 581,811 finish a marathon RUN in 570 events annually. Clearly it's easier to run a marathon run AND host one. #notafanofmassstarts

  • MLambyMLamby Senior Member

    It's an interesting question. It's also one that is difficult to answer. I think the reason why more people run marathons is because it's easier to just "dog it" or quit. Not so much with a swim. You see lots of people with 26.2 stickers on the back of their car who may have done so in eight hours. I think if you are looking at people who actually do both COMPETITIVELY, they are probably equal in difficulty. If you are looking at which is just harder by nature....look at the numbers....marathon swimming is harder.

  • PasqualePasquale Trento, ItalyMember

    Just a few consideration on this topic since I also run regularly (use to run much more in the past) even if not a full marathon..
    If we compare the difficulties to actually perform the sport there is no doubt that swimming is much more complicated then running, there are people who cannot swim and can easily drown in a small pool but you cannot find someone who does not know how to run.
    This is mostly the reason why running is much more popular then swimming, Also it is much easier to perform anywhere and in any kind of climate...
    If we compare the impact on your body and possibile injuries there is no doubt that running is much harder, to run a marathon you need to be fit, people with a bmi>23 can easly risk injuries if runing a marathon, on the other hand more bulky people can swim very well and some fat can also help to some degree in cold waters..
    If you compare a olympic runner Vs olympic swimmer, I think the effort and training required is the same
    if you compare a slow swimmer (~2 minx100m) Vs a slow runner (6 minx100m) ,IMO swimming slow is easier than running slow
    I would also say that running stresses more the cardio while swimming is more muscular and probably thats the reason why marathon swimmers can perform for longer time than runner
    On the psycological side, running is easier then swimming when you are really isolated from the rest of the world
    the two sports are almost at opposite sides, it is very difficult for a good swimmer to run fast and same for a runner, I think thats one of the tricky parts in triathlon
    Last but not least Looking at Olympic record, I would compare a marathon with a 12Km swim, (10 km is usually done in 1h50m)

  • LakeBaggerLakeBagger Central OregonSenior Member

    I’ve been listening to a lot of ultra running podcasts these days (science of ultra, trail runner nation). There sure is a lot of overlap, especially on the mental side of things.

    One big difference is that ultra runners know what the course looks like in advance and can mentally and physically prepare and plan for hills, varied terrain, particularly hot sections etc. We can sort of do that, but it recently occurred to me that with how the wind can unexpectedly pick up, or you get an unexpected current not in your favor at the end, or an upwelling causes an eight degree temperature drop, it’s kind of hard to know what “the course” looks like until you’re on it. It’s hard to even estimate how long it will take or what your pace might be.

    The ultra running equivalent would be the hilly section you thought wouldn’t start for another twenty miles is suddenly starting now and you have no idea how long it’ll last (wind picking up). Or you thought you only had another hour left to finish but it turns out it’s taking three times as long because someone randomly just added another handful of miles (current).

    This just makes ultra swimming a lot harder to mentally prepare for.

    Also, they take sleep breaks!

  • musclewhale89musclewhale89 Alberta, CanadaMember

    It definitely depends on the person. For example me and a buddy have been training to do a half ironman coming up in two weeks. I am 5'9, 195lbs, stocky, and heavily muscled. My buddy is 6'1, 165lbs, lean ectomorph. He's the better runner so he would say running whereas I am the much better swimmer and I would say swimming.

    I have also done both a marathon swim and a marathon run. I would say swimming was much easier and also didn't take as much out of me. The day following the run, I could barely walk up and down the stairs. Also, my time for the marathon swim was much better for the run so that definitely makes a difference.

  • wendyv34wendyv34 Vashon, WASenior Member

    I ran 8 miles once, it totally sucked. :D I'd rather swim any distance than run it, but for the average person, running/walking a marathon is going to be easier.

    Nearly everyone born with the physical capacity to walk/run, learns those skills in their first couple of years. As a swimming instructor, I've seen very few three year-olds who can manage any semblance of swimming. Even those who started in tot class at 6 months just don't have the complex motor skills to swim at an age when they are already pretty good at running. The best three-year-old swimmer I've ever seen was Gary Hall Jr's son, Charlie. They took lessons at my pool for a bit and Charlie could already confidently dog-paddle across the pool like a little beaver. I had the pleasure of teaching Xavier McDaniel's (Seattle Sonics forward) son to swim when he was six. He was comfortable in the water to start with and was able to learn crawl stroke with side breathing in three 30-minute classes. It can take six year-olds up to two years to master that skill. Genetics (natural athletic/physical ability, in this case) plays a part in being good at swimming, but early access and frequent exposure are the most dominant factors.

    I've read some stats: Of people who claim to know how to swim, less than 1% can swim more than 400m without stopping. The percentage of Americans (kids) who can swim varies by race (and economic status), from 40-70%, due to access or lack thereof. Most of us go to the pool and everyone around us is a (pretty decent to great) swimmer, so it's easy to forget that the vast majority of people, even marathon runners, rarely set foot in a pool to swim laps. The ability to swim a marathon is quite rare.


    It's always a bad hair day when you work at a pool.

  • MLambyMLamby Senior Member

    I'm sure this may be repetitive, but....I have done both Olympic distance triathlons and marathon distance swims. Here is where I stand on the issue. Swimming is technically "harder" in my opinion because runners and cyclists have the ground, and gravity, and predictable terrain and conditions on their side, as well as the ability to just sit and take a rest if they need to. Cyclists can glide and the bicycle does SO much of the work. Runners have the ground to support them and to use for propulsion. Swimmers are relying on their own body and varying conditions, and no ability to truly "sit and rest" without recording a DNF. Even taking in nutrition is harder when swimming. There is a reason why the marathon swimming community is so small....it's because it is SO hard. I don't fully accept the "lack of opportunity" argument either. There is water everywhere. People who "swim" will find excuses not to swim. Swimmers find excuses TO swim. :) All the best.

  • IronMikeIronMike Northern VirginiaCharter Member

    I'd rather swim (and fail) around Manhattan than swim even one mile. My knees can't take it and frankly, I can't take it. Meanwhile, lay me down horizontal in the water, and I'm just fine.


    We're all just carbon, water, starlight, oxygen and dreams

  • IronMikeIronMike Northern VirginiaCharter Member

    @IronMike said:
    I'd rather swim (and fail) around Manhattan than swim even one mile. My knees can't take it and frankly, I can't take it. Meanwhile, lay me down horizontal in the water, and I'm just fine.

    Doh! I of course mean "run even one mile."

    We're all just carbon, water, starlight, oxygen and dreams

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