My brief career as a tree planter in the Oregon Cascades. I have never been so tired, before or since.

Ran my first marathon last December. Wanted to die by the end of it. Ran the last, oh, six or so miles on sheer force of will, because my body wanted nothing more in the world than to sit down and drink lots of water.

My dad and I were snowshoeing up the Presidential Range one year while I was in college. We had heard a weather warning before we started climbing, but didn't think the chances were so bad so we went anyway.

When we were 2/3 up the first mountainside, the skies opened up and freezing rain starting falling on us.
The trail, which was the only bare rock part of the mountain, quickly turned into a gushing river and we were completely soaked, as were our packs. This made the packs much heavier and our clothes much harder to move in. Adding the difficulty of walking in water, and we were not doing so well.

I just wanted to stop and wait out the rain, but my dad (who knew better about hypothermia) annoyingly insisted that we keep going. We finally made it above treeline a little after dark, but that was even more difficult because we couldn't see the trail well as it was all rocky and nighttime and still raining.
We found our way to one of the AMC huts and I don't think I'd ever been happier to see anyone than the acoustic guitar-playing dreadlocked hippie taking care of it.

Marine Corps Boot Camp, Parris Island

I did a snowshoe trip that turned into a bit of a Bataan Death Cruise a few years back. Got lost, weather turned, and on top of it all I blew a binding, which forced me to ditch the shoes and posthole for about 3 miles (that's a lot of postholing in crappy weather/deep snow btw). thank buddha we finally ran across someone with a GPS who was heading in the same general direction; they were able to get us back out to the main road anyway.

took me about a week to walk properly afterwards; my quads and adductors were completely shot. I haven't gone backcountry without a GPS unit ever since then, not even on the road bike.

For me, I think it was a five-day stint aboard a historic square-rigged bark that I did in 2006. Though I was in shape for it, the forces of wind and water behind the heavy, traditional, all-manual equipment were so very very strong. We had to climb around aloft quite a bit, continually trim sail and tack, haul boats, row, lift and carry, handle big guns, steer, and all sorts of other muscly work. Though I've done sports training programs and jobs that went on for months or even years, those efforts were spread over time. The ship was the most physical effort I'd ever expended in that short a number of days.

It can really feel great.

Going to see lava entering the ocean. Well, coming back, actually.

The hike out was incredibly demanding, up and down broken lava flows. The 4-mile hike took about three hours.

The hike back was without a doubt the most strenuous thing I have ever done, both physically and mentally. Well, maybe the Ph.D. orals were more mentally challenging, but this was a close second. You see, lava viewing is best done at dusk, and there was no appreciable moon, so the 4-mile walk back was in almost total darkness. We were prepared with headlamps and flashlights, but there was no trail, just a flashing beacon every half-mile or so, beacons that we often lost sight of while scrambling up and down the lava flow. I actually used stars to navigate several times—and what stars! The MrsMoonPie said she actually felt claustrophobic with so many stars hovering over her. The Milky Way was simply breathtaking, and we saw 8-10 meteors as we walked.

We were adequately prepared for the hike, at least. We knew how far it was (though hadn’t really thought it’d take that long), and we had food, water, sunscreen, boots, long pants, headlamps, the works. There were no rangers, no phone access, and very few other hikers, so one could easily have gotten injured and not been found until morning.

We literally had to watch every step, but then, that's about all we could do, since our headlamps weren't hugely powerful. Take a step, look for the next foothold, take that step, repeat, for three hours.

i have to plead the fifth.

Squatting 290 pounds for three sets of five.

Taking care of children. Followed by working in the hospital and running for long distances. I don't have many grueling feats in my past. I've never felt so taxed that I thought I would drop.

I worked on a farm for one summer of college and during alfalfa season loading those bals off of a haytruck and up into the barn loft was incredibly difficult. Those bales weight like 70 pounds and are scratchy! Also it was hot. Also we were required to wear long pants. Much harder than loading boxes of paper [roughly same weight and shape] at UPS which was also hard but not as hot and scratchy.

Recently though training to be a lifeguard was hard. Not because of the swimming but because swimming down to the bottom of the pool to drag a very heavy person playing dead to the surface -- sometimes someone who doesn't want to come with -- was scary and challenging and demaning at once so it SEEMED demanding even though it was probably physically easier.

Nowadays I call anything physically demanding that requires me to be up and dressed before 9.

Riding 47 miles on a bike in 90* heat when the most I'd ridden previously was about 15.

jessamyn, the thing that I thought was unforgivably sucky about loading hay was that the boys got to take their shirts off and I didn't.

in hindsight they always got all scratched up and rashy on their chests from the stickers and soforth, so whatever... but STILL.

that plus they got to stand on the ground at least nominally in the shade of the truck. Me being the smallest/weakest, you guessed it, I got to stand on top in the broiling sun, stacking.

thanks for the flashbacks.

Covering a story in Papua New Guinea, about American plane wrecks from WWII just now being recovered. We had to climb up and down mountains through some pretty dense jungle, carrying television equipment. Plus we'd been advised that there were many poisonous snakes and other scary things including leeches. I liked being so focused on the task at hand - just placing my next step, looking for the next handhold. Physically it was very difficult but mentally it was somehow very rejuvenating to be so incredibly intent on something for such long stretches.

I hope to have some good answers to this question in the next few years!

When I work at a bread factory of a major manufacturer (__________ ____ remebahs!). My job was to catch five loaf pans that rolled off a conveyor and load them on a 36 pan rack and drag them into the 'proofing area' which was maintained at an obscene level of heat and humidity. In the fall and winter it wasn't so bad, but one week in the summer, the temps outside were over 100 ao you can imagine what it was like inside. We also had to switch over pans when the size of the bread we were making changed, which was an adventyure in and of itself. Any labor I've done since seems like Mardi Gras by comparison.

Covering a story in Papua New Guinea, about American plane wrecks from WWII just now being recovered.

Well that there is just super, super cool. I bet you have lots of great stories, Kangaroo.

I don't know that I've ever done anything very demanding physically. I'm pretty much a lazy little weakling.

I'm pretty much a lazy little weakling.

you've given birth twice. that's probably more unpleasant than all our stories combined.

The most physically demanding thing I've ever done was probably a very long bike ride.

I re-shingled my garage a few summers ago. Shingles are a bitch to remove and even less fun to carry up ladders etc etc. I also happened to be doing this during the three days a year when the roof of my garage is approximately 15 feet from the sun.

Acid.

As best I can recall a 10+ hour walk, no breaks. It was my first really long all day walk, and by the time I got home I could barely walk. These days I could do that more easily but I wasn't as fit then, and my legs hurt so much for the next week that I hobbled everywhere.

On paper, it was the Half Ironman I did. At the same time, I'll admit that I trained really well for it and felt really good after finishing. Some of my training rides for it were pretty torturous, though.

I also went to military high school and there was a lot of hazing back then. It usually took the form of some sort of physical endurance challenge. Many a night was spent crawling around the dorm room, doing pushups, situps, and duck walking all over the place. The worst was maintaining a sitting position without a chair. Wow, this is bringing back memories.

I did the MS Bike Tour in New York City. 121 miles by cyclocomputer. I am not particularly athletic and it was quite a trial.

Grimy sweat was my companion: For 7 years I mucked stalls, trained horses, loaded hay, shavings, etc. and worked part time in a machine shop. My back has never forgiven me. None of this work was too extreme when you look at each individual task; but taken together – no days off when you’re responsible for animals – the wear and tear was too much for my back.

I actually became accustomed to my back always complaining and didn’t realize just how difficult it was until I quit doing that: to sleep or sit down without discomfort is a wonderful thing and I had forgotten that that was what was suppose to be normal. Humans are amazingly adaptable!

(Though I do miss being as toned, trim and athletic as I was back in those days...)

I split a driveway out of rocks with a big pick and hammer. It took about a week. The biggest rock was three feet across. Hadda get put these metal wedges in the cracks and whack 'em with the sledgehammer. My hands were torn to hell even underneath gloves. Bone-shaking hard labor in the hot Israeli summer. When I was done people drove and parked on it. It was worth the effort.

I used to participate in the Walk For Mankind fundraisers back when I was a teen. Twenty four miles to raise money for international causes. The blisters the next day!!! I'd always have trouble walking for a couple of days after.

I've spent summers working on my aunt and uncles's farm, and yeah, hay bales really do suck.

And there was the small matter of natural childbirth - twice- with the second baby weighing 9 lbs 6 ozs. But really that was a short span of time. Intense, but short.

Man, I've done a lot of stupid physical labor, but none of it seems all that demanding in retrospect (including an underage job breaking up a parking lot's asphalt and hauling it away in a wheelbarrow). In terms of ordeal, I'm gonna say either datura, or this one time I accidentally ate shrooms and drove an hour, following my girlfriend back to her parents house in 100-degree heat with no air conditioning and a black vinyl interior, listening to noise rock.