What happened?

For the first half of the run, I felt fine. My pace was gradually slowing and there were a few aches in my legs, but both of those were to be expected. I didn't feel like I had a lot of energy, but I had settled into a rhythm and time felt like it was going quickly. I even had some lightning in the distance to appreciate as I ran.

What happened here?

It's clear on the pace graph that something happen at 9 miles into the run (68.7% of a half marathon, statistics fans) but what was the cause? Let's roll back a couple of miles. I said I felt good for the first half of the run, but after the seventh mile my pace starts to decrease more significantly, going from approximately 10:00 minute miles to 11:30. My stomach had ached a bit through the run, as it has done a bit with not really adjusting to the eating schedule demanded by fasting, but after the seventh mile I actually began to feel sick, combined with my legs gradually feeling heavier.

However, at the 9 mile mark, it was my legs that gave up. I've seen it happene to atheltes two or three times, but never experienced it before. My legs just went wobbly very suddenly. I didn't fall, but it felt close. I managed to stabilise them enough to continue an unsteady walk, but running at that point was out of the question.

Was the failure just due to the wobbly legs? What caused the wobbly legs?

To answer the first question, probably not. If you look a little later on the "pace" graph, there's actually one complete stop:

At this point, I did throw up a couple of times, which necessitated stopping completely for a few seconds. Although I had drunk a lot and felt well hydrated, not having sweated as much as I would have running at proper speed, I propably would have been dehydrated after this and unable to continue running for the rest of the course, even if my legs had been able to.

The cause of the throwing up was probably eating only just over a hour before running (two slices of bread with peanut butter and two bananas) or drinking much too much to try to prevent dehydrating.

In my opinion, the most likely cause of the wobbly legs was just running out of energy. I have been fasting for a month for Ramadan which results in usually having one meal and one snack each day, so as much as I try to balance my diet across those meals, I have probably lost a little body fat that could have been used for extra energy. Since the gym has been closed for a couple of months due to the pandemic, I haven't been able to weigh myself, but I will do when the gym reopens in June. I don't feel like I have lost a lot of weight recently, but I did lose a lot when I first moved to Indonesia and despite my efforts I didn't ever manage to put more than half the lost weight back on.

Did you walk the rest of the route then?

Yes. Well, I did try to "run" again for awhile twoards the end of the run when I thought my legs might have recovered a bit, but rather than aerobic exercise, it felt like anabolic exercise.

Every step felt like doing a leg press in the gym. I continued for as long as I could, but with that section also being uphill it was clear I wouldn't be able to keep up even that pace to the end of the run. I started feeling nauseous again too, which was a sign my body wasn't capable.

Will you try again?

Maybe. I'm not sure at this point. Fasting ends tomorrow, which would make everything a lot easier, especially in term of timing of the run in relation to eating, but two weeks isn't a long time to adjust. I 'll think carefully about it.