top of page

Nearly DNF-ing my first 100K race, or: How I Learned to Stop Worrying and Love Going Long

Oliver has been a member of the Camino Coaching programme for only 5 months and within that period he has already gone from 50KM (Camino Lea Valley) to 50 mile trail (Jersey Round the Rock) to his first 100KM.

With wonderful passion and a desire to set his running bar high Oliver found himself with big targets for last weeks Thames Path 100km (his A-goal target would have won the event)

Oliver wrote about his experiences on his brilliant Reddit page - it is such a candid, raw, funny-at-times report that is rich in ideas and self-experimentation that we asked Oliver if he would kindly let us share it with our Camino audience.

Please let us know what you think.

Race Information


GoalDescription Completed?

A Sub 10 hrs No

B Sub 11 hrs No

C Don't DNF Yes


Distance Time Cumulative

25km 02:24:010 2:24:01

50km 02:28:250 4:52:26

75km 02:56:200 7:48:46

100km 04:02:03 11:52

Did my first 100km. Asked this sub if I was capable of ludicrously fast times. Was informed I would not be. Revised goals down but they were still far too ambitious. Faded very badly and at the 3/4 point had a genuine crisis of the soul. Rallied just enough to get to the finish. Learned a lot about myself as a runner and a person. Deeply humbled by the experience, but also grateful for it.


M34 who took up running in 2018 to lose weight. I did my first marathon in 2019. In 2020 I had a breakthrough year and hit a lot of PBs including two sub-3 marathons, sub-37 10K and a sub-18 5K. For a long time I had felt fat and unathletic and I really came to love running; it gave me a feeling of achievement and pride in my body. As I would come to discover, I had become maybe too dependent on this feeling of progress.

Unfortunately I picked up a case of plantar fasciitis in autumn 2020 which disrupted my training until April this year. During lockdown I decided that when I could go outside again, I would spend as much time in nature and the outdoors as possible. What better way than trail ultras.

I built back to weekly mileage of 80-90km with peaks of 100+. I ran a couple of flat 50Ks in June and a c. 75km trail race with 1500m elevation in July. The goal with these had been to finish strong but with an eye to further training. Thames Path would be my first 100km but also my A race for the autumn, and given it was a very flat route, and I was used to planning and executing races well, I was feeling ambitious and decided to go for sub-10hrs.

My last 5 weeks of training. Weekly totals plus highlights:

  • 97km (including the 75km race in c. 8h 20m. I aggravated an ankle problem so started doing some recovery runs on elliptical to take pressure off it)

  • 30km (+ 1hr elliptical) - recovery week

  • 95km (+ 30 mins elliptical), including a fast HM B race (1:27)

  • 106km (+ 2hrs elliptical), finished the week with a marathon in 3:40, most of it at sub 5:00/km pace with some warm up and cool down miles.

  • last week: 78km (start of taper)


I readied my kit and drop bag contents the night before using an extensive pre-race routine written on my phone. I refine and improve the routine every time I race and find it helpful for staying organised. I will add a comment with my kit list if helpful

Shoes: I used a pair of Hoka One One Clifton 7s which I had already done one training marathon in. In training, I run with a pair of insoles to relieve pressure on my plantar fascia and posterior tibial tendon. Over shorter races I use Algeos rear-foot wedges to help control my foot from rolling inward but without the weight of a heavy plastic insole. I had agonised over whether to use these for this ultra, thinking the less weight the better over long distances. Eventually I decided not to risk my tendons for the sake of a few grams, and go with the plastic insole. I think it was the right call.

Vest: I ran with a cheap Aoinijie 18L vest which I think is excellent for the price, plus 2 x 600ml bottles with straws from the same brand (I find camelbacks too heavy and difficult to refill).

I spent the preceding two days carb loading by eating more bread and rice and avoiding fats. I got to bed at 11pm and slept soundly. The alarm went off at 4:30am for a 6:50 race start. I ate a breakfast of a cereal bar and porridge. I drank two coffees to stimulate a movement, which I thought worked (in hindsight this was a mistake...)

I knew that the chafing, blistering and gut problems that might irritate me in a marathon could blow up into race-ending issues over longer distances. So I used a lot of Vaseline in every crevice and threw a fair amount of 2Toms Blistershield powder in my socks and back up socks (although I had to empty some out as it made little lumps in them). I took a pre-emptive Imodium and stored more in my vest for the halfway point. I wore knee high compression socks with another pair of shin compression gear over the top of those. And although it would be a cloudy day in England, I still threw factor 50 sunblock on, just in case.

I took a cab to the start line which cost a fortune but I wasn't about to walk to the bus given the amount of time I would be on my feet that day. The race set off from a small park in West London next to the Thames. The event was mainly for walkers but it also catered to runners who had an early start time. The weather was cool and clear in the morning, and the day was set to be cloudy albeit a little hotter than normal.


My hydration strategy was to drink one of my 600ml bottles between aid stations which were spaced every 10 to 14km.

My nutrition strategy was to get 250 calories an hour from a combination of solid food at checkpoints with a Gu gel in between; I knew from experience that a diet of 100% gels would destroy my insides after 50km, but with plenty of Imodium and a mix of foods, I would be ok. I had some old SIS gels I brought with me just in case I needed something isotonic (to combat dehydration) or caffeine free to give my guts a rest. My parents very kindly followed me in their car between checkpoints throughout the day to provide support, and they also carried a bag of Tailwind. I threw a couple of scoops into one of the 600ml bottles for an easy source of carbs and electrolytes, and to provide another option in case my GI tract began to rebel.


0 - 25km The race was very well organised with an easy check in and bag drop, and we started bang on time. I settled into a comfortable rhythm at around 5:45/km, firmly on 10 hour pace, as we began to move west from the centre of town towards the sights of West London (Kew Gardens and Hampton Court Palace). I said hello to and chatted with a few competitors and told them my target time, which I would begin to regret later in the race. One runner kept overtaking me, but I would pass him when he took walking breaks; he told me this was because he had a sensitive gut and walking made it easier to digest. I would be taking this advice myself later in the day.

Unfortunately I managed to miss a turning early on and cut around 500m of the course. Wrong turns later in the day would more than make up for this distance but it was a bad early omen. The path occasionally turned away from the river and wound back and forth between the north and south banks of the Thames. More than once I would have to ask passers by if they had seen route markers up ahead. I twice had to call out to another runner ahead of me that he had missed a turn and was off course.

Aid stations had plenty of chocolate, bananas and energy drinks which I stocked up on at every chance. I remembered reading, "An ultramarathon is an eating competition with running thrown in" on this sub and was determined not to let this do me in.

The Thames Path runs through towns, villages and near empty countryside, much of it flat and green. In the morning we passed many rowers training, and later in the day there were families playing and picnicking by the water, and after lunch a few merry bands enjoying drinks on boats. There was the occasional turn onto dual carriageways or through uninspiring architecture, but for the most part it was a really lovely tour. The organisers had marked every kilometre and as the event progressed, passers by, walkers and other runners on the path offered plenty of encouragement which was so great to receive.

At 23km, my guts began to unexpectedly grumble, and I realised I might not make the aid station. A wise man once said, "Eat before you are hungry, drink before you are thirsty, and shit before you shit yourself." I had to take an unfortunate trip to a bush and while I had packed toilet roll it was a really bad sign. I took another Imodium earlier than planned and hoped it would get things under control.

25 - 50km

I left the 25km feeling ok but at 30km I began to realise fatigue was setting in earlier than I had expected. I wasn't sure if this was normal tiredness, or the start of a breakdown. My heart rate still seemed under control, so I decided to take the high risk approach and keep pushing at this pace.

I passed the marathon split in around 4:05 and the 50k in around 4:50. However, I had to admit to myself at the 50km point that things were not going well. At that checkpoint I admitted to my parents that I was probably going to reach the next checkpoints later than planned.

At 50km I changed my hat but elected not to change any other clothes or shoes (it didn't seem to make a difference to me). I did reapply sunscreen. I also had to make another toilet stop and noticed GI discomfort starting to creep in. At this point I was still rushing through the aid stations, as much out of frustration as anything else as I knew even sub-11 would be challenging.

50 - 75km

I left the aid station and after a few token miles trying to keep my splits to 6:00/km, on the edge of a 10:15-10:30 final time, once aid station stops are factored in. But the pace slipped very easily to around 6:30/km. At this point I was in around 8th place. The sun had came out and the day felt much hotter and more humid than we had expected. I began running with a women who had caught up to me. An aid station volunteer told her she was the female race lead, and we were currently in the top 15. We were both surprised that the field was so slow today - previous years had been much faster - and we mused on what the reason might be.

By this point I had come to recognise one or two other runners and I recall complaining to them about nausea. Solid food was not going down as easily and the list of things I could eat was dwindling (it would soon reach zero). I went from eating chocolate and bananas at aid stations to drinking energy drinks and 50/50 coke and water mix.

I made it to the 3/4 point still