Ironman or Ultra Marathon - What's TOUGHER? Which is HARDER?

[@nataliamartinkova]

Triathlon days are wonderful in summer. A run early in the morning, a bike commute to work and a swim after work on the way home. But training for three sports where two require enormous time investments (long bike rides and long commutes to pools) requires a specific lifestyle as you say. In contrast, trail running just increases the number of trees in your life, which is always a treat in itself.

[@runningwithsimon]

Totally. And the variety of 3 sports is refreshing. I don't always feel like doing a 6-10 miles in my neighborhood....

[@laurenjackson4314]

I'm glad you touched on the community aspect. The ultra community is so super supportive and fun, and it makes me feel great to help others out along the way. The adventure and journey are also important. Ironman events have an austere feeling to them from the outside looking in. Nobody in star wars costumes!

[@runningwithsimon]

"Nobody in Star Wars costumes" haha true! Maybe I was unlucky myself, but people around me also took themselves VERY seriously - which is totally fine. Your in your bubble and all - I get it. But that's not the vibe I'm looking for myself - I'll goof around on race day

[@adventurecats4816]

Absolutely my experience too. I always felt like an outsider at triathlons, no matter how many I did.

[@PatrickDelorenzi]

Bro… 100 miles for me (even 100k) was WAY harder than any Ironman, even the ones i was racing for time. The fact with ultra trail that makes it harder, is that it’s simply a longer race and most of all, it’s all on your legs. Uphills, downhills, flats, you always need to run. 100 mile is really next level on the hardness scale for me. The training part I found to be harder for the Ironmans as it really takes a lot of time and dedication Grate video and congrats on finishing Tor Des Geants

[@runningwithsimon]

Thanks! 100% with you. And at the end of the day, it's also, what do we prefer? I was glad to have tried ironman so I could say "not for me". Different type of challenge - it was cool to try so I don't regret.

[@PatrickDelorenzi]

@JaneAlope-tr2et running 100 miles continuous in the mountains is harder in my opinion. 25-35 continuous hours of running, pounding the legs, no swim or bike to take a break. Sleep deprivation

[@user-bs1lj3kv7h]

Thanks for another good video. I see it like this…Ironman is like F1 racing with the huge cheering crowds and you are going really fast. But Ultra running is like Baja racing where there are crowds in few spots and you are on your own for really long stretches of the race. I have 5x Ironmans (including Kona) and 10x 100+ milers and both are very challenging and satisfying but for different reasons. I think you nailed it when some athletes are looking for that “next toughest challenge” and ultras seemed natural for me. I’m retired from Ironmans but training for the Arizona Monster 300M so that is my next challenge!

[@runningwithsimon]

Oh you'll be at Monster 300M?! Is it your first 200? I'll be there too!

[@user-bs1lj3kv7h]

@@runningwithsimonno - I have a flat 200m already (fixed time/ variable distance) but AZM 300 is a completely different animal and looking forward to it. See you there!

[@runningwithsimon]

Ironman are very difficult to prepare for given the 3 sports, and you need to be very fit. But I think something else I forgot to say is that recovery is so much faster compared to ultras. After a tough ultra, it can take weeks to get back to normal. For ironman, it took me a couple of days - which doesn't necessarily mean it's easier, but more that by switching it up between discipline, the stress on your joint and body is better distributed. ps: I know it's a bit of a random video - but with Tor des Geants behind me, the question of "what's next?!" came up naturally, and I figured some by be wondering the same with the end of racing season (and beginning of "planning next year season"). I've already started drafting racing calendar for next year

[@hellowill]

How about having to split up your training.

[@laurenjackson4314]

Hmm...bears vs sharks? The longer ultras definitely seem like more of a grind. I have my eye on a Spartan 50K with 60 obstacles for a unique challenge next year. Then have to step up to 50-milers and 100k's. Seems so intimidating right now!

[@runningwithsimon]

@@hellowill yes, the training schedule is much more complex and time consuming for triathlon. No doubt there imo.

[@runningwithsimon]

@@laurenjackson4314 I think ultras are both much much much harder than they sound/look like. But also much easier. Hard to explain. I think a 50k spartan would probably be harder than a 50 miler...albeit mostly different. The the OCR I did, you also had to deal with being wet and muddy - which is fine for a 5-10k. But longer, you'll chafe, and have to deal with blisters.

[@Kbuck5280]

I’ve done a lot of half Ironman races and one full. I’ve also completed many road marathons. I love the challenges that come with multisport but it is expensive to keep up with the latest technology and a gym membership for the swim. Not to mention that road riding is becoming more dangerous with distracted drivers. I took a break for a bit and then did a couple 50k trail races. They are so much fun because you meet nice people, being out in nature is therapeutic, and it’s not so expensive to get into the sport. I also like trail running because it can be technical which keeps your mind busy, helping to pass the time. I started training for Leadville 100 next year because it’s on my bucket list, but I am thinking it’s just the beginning because I love it so much! …I reserve the right to change that statement after the event…

[@vvk]

It is really simple. Ironman is hard on your wallet AND your time (you need to schedule 3 different training types ). Running is much more egalitarian ( more people can practice and participate). Running could introduce more damage to your body especially if you don't prepare it properly ( it took me almost 3 years of rehabilitation to return my knees to 100% after years of just running) So in short triathlons are harder on wallet & free time. Ultras are harder on the body

[@runningwithsimon]

I think you're spot on

[@justinwolf7947]

Great video Simon. I'm not very interested in completing a triathlon, mostly due to all the training. It was interesting to see a comparison of the two sports though, so thank you for the enlightenment.

[@runningwithsimon]

Thanks - yeah the hassle is a bit much. I remember always running around trying to get to the pool before or after work... It was just, ... stressful! Although one thing I remember distinctly and was such an amazing feeling is when I was finally able to swim more consistently. Like similar to when you reach that "infinity pace" when running - I felt the same. I felt like I could go on forever and had finally pass the big hurdle. Super rewarding!

[@gabrielbelangervancoillie7342]

Totally agree with you, Simon! You explained it really well. I’ve done both an ultra-trail (130 km run, 4400m D+) and a full Ironman. Ironman is more technical (you need to master three sports), but pacing is more critical for ultra-running. An Ironman is much easier to complete with minimal training compared to running 100+ km, where you have almost no chance without at least a baseline of training (e.g., 35 km/week). I noticed that around 5% of participants at Ironman Tremblant 2024 were overweight, but I’ve never seen an overweight runner in a 100+ km ultra-marathon. :D Overall, I’d say an Ironman is ''harder to prepare ''for because it’s more expensive, more time-consuming (training in three sports, maintaining your bike, finding pool hours, etc.), and more dangerous, especially during training (outdoor cycling, risk of drowning in open water). However, an ultra-marathon is ''harder on race day''. >>Example from UTHC 2024: My brother, a friend, and I were new to ultra-running. We all bought new shoes a few days before the race, did one practice trail run of 36 km a week before the event, and had never participated in an official trail running event before. Overall: 1- Our friend did not finish (DNF) after 61 km/125 with an average of 22 km per week for a year (not much prior running experience, 5 years of tree planting). He still hasn’t fully recovered (3+ weeks). 2- My brother also DNF’d at 102 km/125 with an average of 30 km per week for a year (completed a full Ironman the year before, 2 years of tree planting). It took him 3 weeks to recover. 3- I finished it, completing 130 km/125 km in 24 hours with an average of 85 km per week for a year (also did a full Ironman the year before). It took me 2 days to recover and get back to my normal mileage (100 km/week). So, if you’re aiming just to finish within the cutoff time, you probably need a minimum of around 35-40 km per week (about 4 hours/week, or roughly 200 hours total) to train for a 100 km ultra-marathon. For an Ironman, you could probably manage with 1-2 months of focused training, doing one half-Ironman each weekend for 3 weekends. The key is to be comfortable on a TT bike and to get your nutrition and hydration right. So, maybe around 5 hours/week for 2 months to ramp it up a bit-around 40 hours of training in total should be sufficient. (I can confirm that, for someone in good physical shape without any training ( that can swim 3min/100m at least**) , completing a half-Ironman under 7 hours is definitely doable based on the experience of some of my friends.) * if you dont know how to swim, add 20h to the total training time. Just keep your head underwater as much as possible, till u can cross the poll without being out of breath and watch some youtube video.

[@runningwithsimon]

Very exhaustive - thanks. 100% agree. Curious - how was UTHC? Might want to do it some day as an excuse to go back to quebec to see the family.

[@gabrielbelangervancoillie7342]

@@runningwithsimon Amazing race ; Race director, staff , volunteers were all awesome people. I haven't much experience to compare it to other races, but it's probably worth it even tho it's ''only 125km '', I just which they had a 100 miles format.. :x With the QMT shrinking to 135 km, Quebec doesn't much of 100 milers. I'm gonna have to run one by myself this winter or something. Btw again, thankyou for all your videos, they're perfect to grasp an accurate ''Feel'' of what it is to run long distance with a positive mind set! Now I wanna run the Tor des Géants like you :D

[@runningwithsimon]

@@gabrielbelangervancoillie7342 Thanks for the feedback about the race and channel - much appreciated! Yes it's too bad there aren't more 100 milers. To be fair, 125km of trails in Qc is roughly equivalent to 160km in Arizona IMO.

[@gitricoachedtriathlon5752]

Hi from UK Simon. I loved this comparison. Having done several ironman races, I'm looking for what's next and have come to ultra quite late. I'm going to do my first ultra in 2025. Will stick with 50k and 50M distances for now though. Thanks for the insight.

[@runningwithsimon]

Good luck! I'll have to come run in the UK some day!!!

[@coloradosheets]

Another great vid Simon, thanks! I've always felt like 100 milers are considerably harder than IM, but I've only thought about the race itself, I think you have a good point that in terms of the training, IM is really intense with having 3 disciplines to train for. But for sure, the race itself is harder in Ultras. I also think about this: what would happen if you switch roles, who would do better: An ultra-runner who didn't train for an IM but showing up and attempting their first IM, versus an IM athlete who hasn't trained for trail 100 and they just show up and attempt their first 100 mile trail race. Assuming the runner has at least some experience swimming and bike (but no actual training), then I have to believe the Ultra runner has a better chance completing an IM than an IM athlete completing a 100 mile trail race.

[@runningwithsimon]

I think you're right - but that is assuming some base line level for the swim - which imo is mostly about technique (and not fitness). I always felt very humbled when I'd go at the pool to swim say, 1000 yard. Get totally destroyed at it - but also, seeing that old lady in the lane next to mine - having started before me, and still going at it. And being at least 20-40% faster than me.

[@Shevock]

Also, bicycle falls are a real danger in Ironman training. But if you cycle for cross training in a running event, you often aren't pushing as hard or far, or even need to go on dangerous roads. You can cross train on rail trails.

[@Shevock]

BTW, I appreciate both. I'm not likely to run either. If I accidentally do one it will be an ultra at a time event.

[@runningwithsimon]

Very true about cycling - and the crashes on race day are very real too. Plus extra speed = bigger injuries. I was amazed by how distracted riders were. It was a real hasard at feed station with people zooming past full speed, or people catching a bottle without looking ahead (and also not having hands on steering bar/break), people re-entering the speed lane without looking backward. And also frankly, very terrible handling skills. Having done myself both gravel races and MTB (and some road in that gravel race), the skill level was much much lower in triathlon. It was very clear to me that the pre-conceived idea that some ironman mostly train on indoor bike in their garage was actually true. If anything, I was glad drafting was illegal because some of them I would absolutely not trust to follow my wheel!

[@JoelNads72]

Dans mon cas. J'ai choisi les ultras parce que j'étais trop lent pour la course sur route. J'ai fait un demi-marathon et après le premier km, j'étais seul pendant plus de 2 heures. Puis j’ai découvert le trail et c’était plus une question d’endurance que de vitesse.

[@runningwithsimon]

Oui c'est ca. La grand question en trail c'est "est-ce que tu peux continuer", et pas tant "a quelle vitesse peux-tu courrir" - ce qui est egalement une question qui me plais plus. Je ne suis pas lent a la course en soi (mais pas le plus rapide, je crois 3h23 pour le PB marathon), mais je n'ai aucun interet a essayer d'etre plus vite

[@runningwithsimon]

ps: et le 'rapidement j'etais seul' etais exactement mon experience dans la nage pour IM. Je suis tres tres tres comfortable dans l'eau. Mais je n'ai jamais appris a nager de facon 'efficace' alors je ressemble plus a un chien qu'un nageur. Et quand sortais de l'eau, j'etais vraiment 'back of the pack' avec les grand-mamans (et felicitations aux grand-mamans!). Mais ensuite des que je saute sur mon velo, je passais les gens tres rapidement

[@Zurnimal]

I was told by someone who did a bunch of ironman’s and a few 50 mile ultras that the 50 mile Ultra was tough, race and recovery. Never did an Ironman myself so it was good to hear your thoughts!

[@runningwithsimon]

Intesting - I think i would have said 50 miles easier than IM but I guess that's very close and depends on the race. Ultimately, best is to do what we enjoy anyway

[@Zurnimal]

@@runningwithsimonfrom what she said, using the same muscles for 10 hours was the reason.

[@literarybeard2259]

Simon- I’ve really enjoyed the variety of 100 milers you’ve been able to discuss on your videos. I am curious if you’ve ever gone through all your runs and ranked them for their particular uniqueness (Most Technical, 2nd, 3rd) (most intense climbing, 2nd, 3rd) (most mind numbing, etc) ? I finished my first 100 and am really starting to get the itch to do a few next year - plus many seem much easier than what I started with - so I’ve got rose colored glasses.

[@runningwithsimon]

It's a good idea and I've considered doing something to that effect for a while. The closest to that which I've done is go through my top5 in the video I talk about how to pick your next race. Here: kzbin.info/www/bejne/gKndkmuprsyHZqM

[@jonathanbouchard12426]

Great video!

[@runningwithsimon]

Thanks!

[@fd318]

Great video! As always! My 2-cent build: ultra marathon is impacting the same muscles for a long period of time, while there is more variety in Ironman. Ultra marathon is probably more demanding physically as the body is always hammered on the same muscle groups. Makes sense?

[@runningwithsimon]

Totally - and I think that's why it takes me so much longer to recover from an ultra marathon. And it's not just the muscle, but also joints like ankle and knee. And my achilles. My ironman, it took me very little to feel like I was ready to go full blast. Which, you know, nobody wants to feel like crap, so that was a good aspect of ironman. You push your limits, but felt like you're not wrecked so much.

[@-esox-3714]

Great comparison video, many helpful insights. Personally, I haven´t done both and kind of think about this video`s topic for some long term planning. On one hand, as I am trying to learn proper freestyle- technique for the last 6 months and progress is slow, i´d go for the ironman being harder. Running comes natural, only that I seem to be prone to running- injuries, so scaling up my running to the needed volume might be a challenge without getting injured.

[@runningwithsimon]

I love water and I've very comfortable in it - but I'm not a good freestyle swimmer. I actually did most of my ironman using breast stroke.... But yes, risk of injury is high with running only. I think that's also why I recovered so much faster after my ironman (vs. ultras)

[@mark_verbos]

I feel like these days lots of people go to Ultra Running after doing an Ironman. I have done 2 Ironmans and 4 Marathons, but never an ultra. I'd like to do an ultra. Maybe next year. At the same time, one of my employees is getting into Ultras, but he has never done a triathlon.

[@runningwithsimon]

It's true - one of the reason I made this one was actually that a common question you hear is "I've done 3 full IM and want to run 100 miles ultra - how much do I need to train".

[@Gerus2000]

Hi I m full time worker, have done 70.3 ironman, 50 km 3000 m elevation gain trail running, 400 km 8000m eg ultra cycling race. I think in terms adventure , ultra cycling is more, because you will see much more. And now it is a lot of multidays ultra cycling, above 1000 km. Should consider this sport Simon... But very good content you've made 👍...

[@runningwithsimon]

Yes agreed with you - it's a nice sport. Haven't done it myself but know people that did. Like Ryan (another youtuber). Bike packing sounds fun too. Moving on foot put things in a different perspective and brings you in more rugged place, but biking can be amazing too. I don't have the technical skills yet, but that's something I do consider for long term. Probably not racing, but more bike backing.

[@shipleyag]

I think they are both very difficult but for very different reasons. Training for Ironman feels like having a second job and it’s a little less accessible because of the financial aspect. The mental toughness is there for both but, like you mentioned, with IM you’re not going all night. Ultra feels more laidback and natural to me. Maybe because you spend so much time in the woods. I enjoy both. I find the culture for both are very accommodating and helpful. I have given, and received, help from other participants in both disciplines. Maybe it’s because I’m closer to the back of the pack than the front but in my experience, the people I meet in both disciplines are just competing with the person in the mirror.

[@runningwithsimon]

Glad people were helpful. And to be clear, I'm not saying that nobody would help in IM and that everyone will help in trails (I guess I did phrase it more in absolute, which is not my thinking so my bad) - more that I felt a trend that way. The second job thing is so real. But it's like having a second job - and except of being paid...you pay for it! But it's of course a nice sport that many enjoy - otherwise it wouldn't exist.

[@adventurecats4816]

I have done most distances of triathlon, from sprint to full iron distance. Running was always my weak link. Now I'm a trail runner exclusively. The main difference I found was triathlon has a high level of snobbery and exclusiveness. If you don't have the best kit, best bike, etc you aren't really one of "them." Trail running, on the other hand, is full of misfits, weirdos, and people out to have fun and test themselves against themselves. Trail runners are much more cool and open to newbies 💖

[@runningwithsimon]

I had felt that difference myself even when comparing tri vs gravel. Gravel riding, I was riding my big and heavy MTB. And instead of looking down on me, folks were much more likely to cheer and realize that - dang dude, how can you keep up with us! (In a good way - like wow impressive performance!)!

[@cedrux911]

Great video, but my question now is: can you do both? Like training for triathlon focusing on running and long runs and maybe do some ultras sometimes a year?

[@runningwithsimon]

You can certainly do both. I did both - I was mostly racing ultras, but for the Leadman (a mix of mountain biking and ultra running in leadville), I had to cycle too. Then decided "bah, how hard can swimming be anyway". I think it's not the right approach if you want to perform well. But if looking only for finish - it's fine

[@runningforme]

18:27. You can trip off a cliff, stumble and die. I love it. 😂

[@runningwithsimon]

Best to avoid this if possible!

[@OmahaTonyG]

How many Ironman races have you racing all night and into the next day?

[@runningwithsimon]

100%. Although to be fair, it'd be terrifying (and frankly dangerous) to have folks go through the swim in the dark. Same with cycling!

[@3WalkingPoles]

Ironman is a race of a specific length. There are triathlon races which are multiple times longer and of course, they last through the night(s). I think it would be fairer to compare 50k ultra and Ironman.

[@runningwithsimon]

@@3WalkingPoles I walk through this in the video and why 100 miles. A 50k is really not the right distance to compare - one could argue for 100k if you go for time, but the gold standard of ultrarunning is 100 miles. There are of course much longer races too. And at the end of the day, most of the points from the discussions in the comments, and in the video, the distance you pick doesn't matter all that much

[@toddboucher3302]

Kind of funny I guess well since I’m a horrible swimmer I guess ultra would be more in line with me. Made me laugh when you said hopefully you’ll see which one is right for you. I thought I have no doubt on that matter at all good thanks again.

[@runningwithsimon]

I'm super comfortable in the water, but I'm not an efficient long distance swimmer. So when I was exiting the water with barely a few minutes before cutoff, I was very back of the pack. Which was certainly an experience...!

[@Kelly_Ben]

The expense and time requirements rule out tris for me. I joke that i already have enough expensive, time consuming, dangerous hobbies! 😂 Even though I'm type A, I absolutely love the environment and camaraderie of ultras. I carry extra gear for other runners, like knee/ ankle braces, salt tabs, etc. It's us against our training, gear, and stomachs. Us against the weather, terrain, nature. I'll never podium, so being able to perform as well as I can, in gorgeous places, accomplish huge goals, AND be the best "sportsman" I can be, is my happy place. Huge props to triathaletes, but I'm an ultra girl through and through.

[@Cinefilasthenos]

Ironman is nothing but profiteering, speculation, a beast that wants more and more and more money and offers much less. More or less like UTMB (that's why they collaborate now). I would never spent a dime on it, always preferring to support local and non prominent races. (I wrote the comment before watching the video, curious to see what have you said about it, if you have... 😀)

[@runningwithsimon]

I didn't comment on it in this video, but did go through in another (see link below). And to be fair, UTMB takes a lot of the heat, but I've seen other race organization be just as greedy (or worse...). I think it's something to be vigilant and aware. kzbin.info/www/bejne/o5a0nJltr9qKeK8

[@Cinefilasthenos]

@@runningwithsimon Nobody said that trail community is heaven. Or UTMB is the bad guy and everyone else is an angel. Although, UTMB and Ironman (I do not consider the latter part of the community, anyhow) are bad guys 😉 We should be careful where to spend our money, and where we volunteer, as lots of races, who, beyond the shadow of a doubt, make money from races, obviously use volunteers as unpaid employees. On the other hand, if we would be that picky, we may have a hard time finding (many) races to run and enjoy 😄

[@mcfarvo]

Firstly, the MegaMan intro/title screen is 👨‍🍳 💋 Secondly, thanks for your nuanced opinions on this topic 👍 Thirdly, would a fair analogy be that if this was BDSM, then the Ironman would probably be the Dom and the Ultrarunner the Sub 🤔 (of course, in any extreme endurance sport, the athlete is both the dom/sub as the practice is essentially sado-masochistic) 😂😢 Jokes aside, thanks for this video!

[@runningwithsimon]

haha I didn't expect your 3rd point!

[@Bo-Bland]

IMO. And I’ll have to do a video on this as well. But it goes like this from level of hardness. Marathon, half Ironman, 50k, Ironman, 50 miler, and so on. The Ironman isn’t even close to being on the same level of a 100 miler.

[@runningwithsimon]

Very interesting! I hadn't considered ranking like that but it's a smart idea. I think for me I'd say HM -> Full M -> 50k --> Half IM -> 50M -> IM -> 100k -> 200M -> 100M (but that's just me, and I know some people will have a stroke reading the last 2 entry...which isn't a typo) But I'm a very bad swimmer and decent runner which I suppose skews things to the right. But I suppose it also very much depends on the course - I know 100k that are harder than some 100M, so I'm sure there are 50k I've consider harder than half IM.

[@Bo-Bland]

@@runningwithsimon Thats interesting. I could be persuaded to put the 50k and the half Iron as equal in difficulty. But we both agree that course difficulty can change all that very quickly. So, for this ranking I'm going with your basic 50k, nothing crazy. for the ironman and the 50m again it's a toss-up so i could go equal in difficulty. As for the 100m and 200m I cant say. I haven't yet done a 200. Its on the to do list for 2026. I know that100milers destroy me so I'm having a hard time thinking the 200 would be easier. Though I do understand where you are going with that thinking so I'm going to have to get back to you on this one.

[@runningwithsimon]

@@Bo-Bland At least for the two 200M I did, you had such a comfy buffer regarding cutoff that you have time to take care of yourself - which makes it a bit more sustainable. If you struggle, I could always take a nap. And even sleep 2-3hours without even having to think about cutoff. That's a style that suits me better than always looking back over your shoulder and having to press on even if you know a break would be helpful physically.

[@kadlecjakubb]

I think that 100 mile ultra (or trailrunning in general) would be better to compare with triathlons like Norseman, Celtman, Himalayanman etc. there are guite a lot races like those. You have to swim most time in dark/night, then bike with a lot of elevation gain, and then you run marathon on trail. I think it will be also a lot more adventurous than "classic" ironman, and the community would be closer to the ultrarunning community :)

[@runningwithsimon]

But then why not compare those to 200+ miles race?

[@Alexander-le7qk]

How to master fueling for ultra trail running?)

[@runningwithsimon]

Not sure if you saw this video I made - can be helpful at least in planning. Then it's about practicing this fueling strategy in training - upping your carbs consumption gradually to increase tolerance. That's how the sport dietician we had on our podcast suggest going to it. kzbin.info/www/bejne/epyrkJSDmMmEeNE

[@Alexander-le7qk]

@@runningwithsimon Simon, thanks! It's a very useful video as an intro to the topic. For 10+ hours races this is a critical part of the game which certainly deserves more investigation and sharing practical advice

[@runningwithsimon]

@@Alexander-le7qk it becomes problem solving and case by case very quickly. No 2 race is the same for me past that point. Practice helps mostly in knowing if I can or can't eat something

[@alienzoup]

You should rename your intro to Ultraman hence the megaman theme song lol

[@runningwithsimon]

I wonder what your super power/weapon would be after defeating ultraman!

[@fjhidalgog]

From my eyes and personal feelings, the ultramarathon is the toughest. Running for days is not at all easy.

[@runningwithsimon]

"Not easy" is one way to put it haha! At Tor des Geants about 50km from the finish I was chatting with a girl that was really struggling at the aid station. She stayed longer to sleep a few more hours, but when I left she turned to me and said "it's not such an easy race, hey?!"...haha nope, not easy!

[@khwan1]

I've completed a full Ironman and a few 50K ultra with 8K feet of elevation. To be honest, the 50K was harder for me. In an Ironman, you constantly change the muscles you are using during the race. However, in an ultra, you keep using the same muscles. Once they get fatigued, it's not easy to recover. My goal was to finish the race within the top 30% of my age group.

[@runningwithsimon]

So true about muscle group. And I think that's exactly why for me recovery was soooo much faster after an ironman. Which, well is a point I'd give for IM. Less likely to developed chronic overuse injuries, and it's annoying to feel like a penguin for 1 week after an ultra...

[@reknirbecurb]

You can actually die in an Ironman swim. That’s all.

[@runningwithsimon]

Yes a surprisingly large amount of people do. I think moving away from mass start and going into staggered start probably helped.