My first 100km run

It's been long since I did this run and I originally wrote the bulk of this post in the week after, but recovery was tough and I lost the drive to continue writing after a couple of weeks. Having looked at this draft every time I log in, I figure it's time to finally publish it.

My plan in 2019 was to build up distances and attempt an 80km (50 miles) race. Finding a suitable race abroad was difficult so it was only when I got back to the UK that I found something doable in the timeframe - a 55km race around London and so I shifted the 80km goal to 2020.

With everything that happened in 2020, all of my races got cancelled. I took a whole month off running to do a cycling challenge, which kept me fit, but I hadn't really built up to any consistency. I don't generally rely on races for motivation, but I didn't particularly want to beat my body up if there wasn't a goal in mind.

In mid-June 2020, Joel Runyon asked me to sign up for the challenge he was putting together - The Longest Day Race on Saturday 20th June. Sunrise to sunset around a track. I love the idea of timed track events and it sounded like something I would be up for, but I initially thought I had something on that weekend and turned it down.

The Thursday before, my weekend had become free and I had convinced myself to take part. I discussed strategy with my dad and uncle, to keep it a continual effort if possible, and figured I could always just walk if running was no longer an option.

Whilst aiming to try and complete as much of the sunrise-to-sunset as possible, my main goal was 100km.

I was on-call for the whole of Friday and went food shopping late in the evening to stock up on food. I had this image of me being hungry throughout, so I bought a range of items of food; sweet, savoury, salty items, drinks etc. I wanted to have everything I'd fancy on hand in order to give me the best chance of having a good day.

My attempt at an aid station

So whilst the event I was unofficially doing was a self-hosted track event, all of my local running tracks were shut because of COVID so I decided to do loops around my parent's house. I think it's good to have washroom facilities available and it was just logistically easier to do it around there, even if there are quite a number of hills I'd have to contest with.

Training up until this point was so-so. I'd completed a 100km week a few weeks before, finishing it OK but a bit strained. The main thing I was lacking was long runs. The most recent long run was a couple of months prior and all of my recent runs had been a half-marathon or less.

Anyway, I got up at 04:00 to get ready for a 04:43 sunrise start. Sporting my Chiang Mai marathon singlet for a quick picture and off I go.

My strategy was to try and keep the heart rate low, in order to stay in the fat-burning stage and to put as little strain on the body as possible. I wasn't bothered about pace as the goal was just to complete 100km.

I was starting out with ~10km loops and the first 30km flew by. In hindsight, this was too long away from home & fuel but it meant each loop took a good chunk out of the goal.

Just after the marathon distance, I recall feeling hot and salt crystals were already forming on my body. Losing too much salt is a big issue for me because muscles start to cramp and that can be the end of a good pace. In the ULTRA London event in 2019, the last 9km took me about an hour because it was during the peak time of the day. So being pretty conscious of this, I tried to keep on top of electrolytes with salt pills and fluids. Surprisingly though, I just wasn't feeling hungry (big red flag here). I'd just ran a marathon and was no more hungry than when I'd finished a 10km.

The next loop ticked off 50km. I'd say it was starting to bite at this point. Given this was only the 3rd or 4th time I'd ran this distance, and I still had the same again to go, I probably knew this was the end of feeling good. I was also paranoid that my watch would crash at some point so I saved and upload the event. 50km before 10am.

My family were going out so I was on my own when I finished a loop and got back to the house. I got through to 60km and then it really started to kick in. I walked a large chunk of the next 10km and had assumed I'd be walking the last 30km. I called my uncle at 70km to let him know how I was getting on. He said he wanted to make sure I wasn't going to call it a day and he was already on his way up from London to come and run with me, along with my dad and a family friend.

This was a huge boost, especially when given how much easier running is when running with others. I decided to do 400m loops around my estate to kill time before they all arrived. I think I got to about 76km.

We ticked off another 6km and got back home. I'd ran most of the lap, which was a lot better going than the previous 10km, so I was hoping I could carry that through to the end.

My form was faltering and my feet were starting to develop blisters, so they now needed sorting. We fixed up an ice bath to try and reduce the swelling of my feet. My uncle had brought some CBD balm and I massaged it into my legs. I really don't know think it helped but I was willing to take anything.

With only 18km left, we pushed on for another 6km and I went through a double marathon (84.4km) without it even clicking. It's weird how that happens – when your goal is something higher, these previously big milestones are just a passing thought. I'd been through a half marathon, marathon, 50km, 50 miles and a double marathon not even thinking about them.

88.7km in, I could really start to feel the fatigue now. My brain was starting to melt from the heat and I was zoning out from conversation when sitting down. I couldn't bare the thought of doing 2 more 6km loops so I suggested we go for an 11km loop to get it over and done with.

The last lap was one of those times where you just question everything you're doing, but looking back it was the best bit of the day. You realise you're about to hit your goal and yes the pace was pretty slow, but I charged along determined.

With 2km to go, something in my mind just flicked on and I started to run. Everyone else was behind me so stopping was not an option and I ticked over 100km a couple of hundred metres from home. In my head, the ending feels like some dramatic event out of a film but perhaps that's just how I recall it many months later.

And so basically that's it.

Now, recovery was something else. I knew my feet were going to be pretty rough, but in the following days I managed to lose 2 toenails and developed 3 further black nails. I tried to go for a walk a couple of days later and my feet were so swollen they were so tight in my shoes. I would find myself unable to stand up straight because my stabilizing muscles were exhausted. I also underestimated the sun and burned my shoulders. Lessons learned!

For sure I'll do this distance again (and further!), so until next time.


  • Distance: 100.51km
  • Moving time: 11:17:04
  • Total time: 12:57:57
  • Elevation gain: 1032m
  • Steps: 110,786
  • Burned: 5730 calories