Mt. Rainier In One Day Versus an Ironman Tri

I couldn't help notice reading on a trip report where there was mention of ascending and skiing Mt. Rainier in one day and it not being very hard. I have a buddy who has completed an Ironman in under 10 hours and when he attempted to climb and ski Rainier, he said it was the hardest thing he's ever done. I have never heard anyone say an Ironman triathlon is not very hard, but I find it kind of odd people would be saying to climb and ski Rainier in a day is not very hard as if it has become standard these days.

Am I missing something here, or does there seem to be a special genetic breed of people up there in the PNW in where a change of altitude of 9,000 -14,000 vertical feet doesn't have any affect?

Then again 20 years ago, people thought doing an Ironman was the most amazing thing. Now, these events fill up so fast, its as if it is as standard as doing a local 5k race. I'm guessing in a few years a one day ascent on Rainier will be as standard as doing a 5k race?

A triathlon at sea level and mountaineering are two completely different things. I've seen marathon runners get crushed by the Muir snowfield and seen very strong mountaineers get crushed on runs at sea level.

Yes, you'll have generally strong cardio fitness doing either, but both are fairly specialized endeavors using different muscles in different ways. It's also a different mental approach, I'd guess. Inevitably, the people who do either at a high level have being participating and focusing on those activities for years, which is how they get to that level of performance.

For me, skiing Rainier in a day isn't to bad. After all it is just walking, and I have been doing that since I was two years old I do find that I get a bit fatigued above 12k though.
Now an Ironman, that's a whole different story! If I could survive the swim, I might have a chance at completing one. Unfortunately it turns out that it is quite difficult to doggy paddle those kind of distances... It all comes down to what your into and your training.

some people are affected by altitude much more than others and being prone to altitude sickness has little if anything to do with one's fitness level. You may be in peak physical condition and still need an acclimatization day or two at 10k before going higher....that just has to do with how your body is wired.
I've done Rainier in a day...don't ever need to do it again, camping out up high and enjoying the scenery is as much an enjoyable part of the trip as the climb itself...but to each their own

I agree that the elevation will be a big problem for people who train and race at sea level. Also the surface should not be underestimated. Walking on snow or skiing is quite different from the hard surfaces they run and bike on.

Few years back I skied Baker with a guy who was running marathons under 3 hr and was generally in much better shape than me. He barely made it to the Coleman-Demming col where he waited for us while we skied the summit. The issue was his ankles and hips, he just was not used to the ski specific movements.

I have done both.
I did the October 1983 Hawaii Ironman at age 21.  I finished in 10:42:50 which in those days was pretty good.
I climbed and skied Rainier in about a day in July 2006 at age 43.  Our party took a quite leisurely pace with many rest stops.
The Ironman was WAY harder.  The reason is simple: it was a race.  I maintained maximal sustainable pace from beginning to end, with no rest longer than about 30 seconds in a chair to change shoes.  If I had paced myself in the Ironman as we did on Rainier, taking several sustained breaks, the experience would have been totally different and much, much easier. 
Really, though, the two are apples and oranges.