Which is tougher: Ironman or ultra marathon?

 










I really can’t complain about my year. After suffering a severe tear in my left calf in January, followed by a mild Achilles tendinopathy, I was only able to return to running end of April – but i compensated with quite a bit of swimming (in February-March) and a lot of biking (April-May). Then in July I competed in a 65-mile mountain run, the Vichy Ironman in August and the 100km Millau road ultra in September.

So quite a few people have asked me: which is more difficult, Ironman or Ultra?

Well, first of course it depends on what kind of ultra we’re talking about – you can’t compare apples and oranges (or fries and Brussel sprouts). Certainly the Beaufortain mountain trail run, with its 21’000+ feet of vertical elevation and highly technical trails, was in a class of its own and took me to places an Ironman never could – if only because it took 28 hours and everything I had to complete. By the same token, I’ve done 50 miles footraces on flatter terrain that were easier: quicker finishing time yet more relaxed pace (with more frequent stops to sample the great food at check points).

So the ultra marathon that I feel is most comparable to an Ironman is a 100km road race, with similar finishing times (i've also read that elsewhere). Mathematically it bears out, if you are so inclined, i.e. 3k run equivalent for 1k biking and 1k run equivalent for 4k swimming, so an Ironman is (3.8x4) + 180/3 + 42 = 117km in terms of time. Presumably also endurance effort, but that's what I'm here to find out. Hmm...
Anyway, having completed both a month apart, I feel quite well placed to give an informed opinion – though it still only remains valid for me. The first took me 14h40mn, while the second took me 13h40mn, and I would attribute the hour difference to two factors: the high heat at the Ironman (35°C) and the fact that Ironman^TM couldn’t be bothered – despite the high entry fee – to give out anything more than the sponsor’s gels and bars (no bloody savory food, discounting a few random Tucs!) (whereas at the Beaufortain they were cooking pasta soup and serving coffee at 3am at the top of a mountain). And then of course there's my lack of specific training… But that only makes my answer more valid.

Because definitely I would say that the 100k ultra marathon is the more difficult challenge, and anything above that, or with considerable elevation, definitely more so. (Though training for an Ironman – particularly in a dedicated and specific way, which certainly wasn’t my case – is a lot more time-consuming.) I didn’t doubt that I could finish either going in (though in such endurance events it is of course always a possibility), but during the races I never really doubted that I would finish the Ironman, whereas I did have some moments during the 100km whether I could finish, wanted to finish or would finish in one piece, when my goal had been to walk only the hills and after that as little as possible (goal accomplished actually, even though my pace at the end was more a shuffle than a jog). And I was able to jog up some stairs at the end of the Ironman, whereas my right knee had locked up by the time I completed the 100km.

And I had trained specifically for this race. Up to 50 miles per week of running (a huge max for me), while I’d only swum 5 miles and biked 200 miles in the 3 months leading up to the Ironman (that would account for my time…). Not to mention that I have a hard time in the pool after about 10 minutes and I’ve never been a fan of the bike and all the apparel that goes with it.

However, I will say that while I entered some dark spots at the 100km that didn’t occur during the Ironman (i think due to the change in activity from swim to bike to run), I did find it more intense. You always seem to be in race mode, whereas at the 100km, even though I was aiming not to walk, I never felt as pressured (much sorer, yes, but not pressured). And I took my time to eat, chat… 
And there was definitely a sense of pride and accomplishment particular to finishing the Ironman – it was my first (which doesn’t imply there will be a second, though I can’t rule it out), and you never forget your first time…