Race Information

• Name: Kuala Lumpur Standard Chartered Marathon
• Date: October 4th, 2026
• Distance: 26.2 miles
• Location: Kuala Lumpur, MY
• Website: https://www.kl-marathon.com/
• Strava: https://www.strava.com/athletes/6676640
• Time: DNF at 31km (Got to 29km in ~2:40)

Goals

Goal	Description	Completed?
A	Sub 3:30	No
B	Finish	No

Splits

Kilometer	Time
1	5:19
2	5:10
3	5:12
4	4:49
5	5:22
6	5:01
7	4:51
8	4:51
9	5:04
10	4:54
11	4:59
12	5:13
13	5:25
14	5:24
15	5:27
16	5:30
17	5:17
18	5:10
19	6:50
20	5:13
21	5:52
22	5:55
23	7:36
24	6:07
25	7:48
26	5:59
27	5:38
28	5:44
29	5:31
30	25:14
31	11:06

TLDR

DNF at 31km after starting too hard, progressively overheating/dehydrating, and eventually developing severe nausea and vomiting. I had been training for a 3:30 marathon and generally hitting my training paces, including a 2:45 20-miler, but my HR was significantly higher than usual from the start despite the pace feeling manageable.

I eventually slowed down, but by ~25km I was already experiencing symptoms similar to a previous overheated long run. At 29km I stopped, drank some water and iced myself down, but soon after started vomiting. I tried to continue but developed cramping and couldn't tolerate my carb drink, so I walked to 31km and eventually DNF'd after vomiting again and becoming increasingly weak and lightheaded.

Looking back, my biggest mistake was ignoring the HR warning signs and trying to hold my goal pace when my body clearly wasn't having it. I'm also wondering whether my fueling/hydration strategy contributed to the GI issues, despite having used it successfully in training.

The main lesson: if your HR is telling you something is wrong, don't ignore it. Slowing down and reassessing is a lot better than pushing through and being forced to DNF.

Background

27M, 57kg (125lbs). I started properly training and decided to sign up for my first marathon just over a year ago around August. I started out by building my mileage to maintaining 70-80+k weeks for a few months prior to starting my first Pfitz 18/55 block in June this year.

Training

In training I was generally pacing my runs with about a 3:30 goal finish. I was pretty consistently hitting the target paces in most of my runs until I took a weekend off for a hike up Mount Kinabalu (highest mountain in my country). The week following the hike my legs were a bit beat up and for the final long run with goal marathon pace I blew up from poor pacing and dehydration/heatstroke like symptoms in the final third of the run after going out faster than I should have having not recovered fully from the hike and ended up taking a rest in my car to cool off for 15 mins before finishing the last ks at an easy pace.

Two weeks later I had my last 20 miler on the plan which I finished in 2:45 feeling quite strong which made me think the 3:30 goal was still within reach with a bit of tapering and my subsequent runs also were indicating 3:30 should have been achievable.

Pre-race

The race starts at 3:30am so I started carb loading from the Friday and ate ~500g of carbs per day mostly consisting of white rice. I tried cutting down on fat to make it easier to eat so much carbs.

My fueling strategy for the race was the same homemade carb drink I'd been using in my long runs for the past few months. I was aiming for 90g of carbs per hour, broken down into 3 x 30g servings taken every 20 minutes. Each serving was in one of those small disposable baby food/mini drink pouch-type containers, which made it easy to carry and take at regular intervals. The drink itself was made from 60g maltodextrin + 30g fructose, mixed with 90ml of water and half a teaspoon of citric acid for flavour. More recently, over the past month, I had also started adding 1.2g of salt, which worked out to roughly 500mg of sodium per hour.

I had used this fueling strategy successfully in training, so I didn't expect the carb drink itself to be an issue going into the race.

I slept early on Friday night and woke up early around 6:30am (7.5 hours sleep) hoping to go to bed early and get a full night's sleep before the race. On Saturday I got in bed at around 5:30pm but struggled to fall asleep and had broken sleep until around 9pm when I properly fell asleep. Woke up at 12:30am on race morning and had 2 slices of toast with some Nutella before optimizing my weight at home and heading to the race start point.

Got to the race village, used the porta potties quickly and then changed into my race shoe (Adios Pro 4) started warming up around 3:10am, did some dynamic stretches and ran for under 5 mins with a couple of strides then went to line up at the start pen.

Race

When I entered the start pen I immediately started sweating a bit and it felt warmer than usual. Checking the weather forecast and my watch it should have been ~26C according to the weather forecast and 29C according to my watch, with 89-94% humidity. Both of these are similar readings to when I usually do my long runs, so maybe it was heat from the crowds that I was feeling/nerves.

Malaysia also has been having some haze problems from fires in Indonesia and it was slightly hazy in the morning (could see it a bit but no smell). Idk if that played any part in what came after.

When we flagged off I immediately felt a bit flat and was struggling to find a rhythm while trying to pass people for the first few km. I noticed my HR being higher than usual for any given pace but chalked it up to just nerves and hoped that it'd come down once I managed to lock into a pace and once I wasn't weaving to pass people.

Before the race my plan had been to try to keep my HR in the 160s for the first half and then let it drift into high 160s to low 170s after around 30km. I had an alert on my watch that would beep every time I crossed 172 (~177bpm is where I think my threshold HR is from previous efforts, with my max HR being 198).

Looking back on it now I was drifting slightly over my HR limits and clung to my target pace for too long, despite that being a pace I could usually handle at a lower HR. Since the perceived effort felt as easy as usual (in retrospect maybe adrenaline and a bit of denial) I thought maybe my arm strap HR monitor was off by a few beats or that even if it was correct that I'd be fine.

Looking back at the data, my average HR for the first 10km was 172 with maxes touching 177-183 momentarily at times. I assume this was on some climbs etc. This first 10km was mostly on wide city streets. I was feeling it a bit in my ankles because my race day shoe doesn't do me any favours when there's road camber, but it was manageable.

The next 10k I got a hold of my senses, stopped clinging to 5:00/km pace, slowed down a bit and got my average HR down to 165 from 11-20km. These 10km and almost all of the remainder of the race is on elevated highways and there was a lot of road lean/bank to the road at some sections which I was feeling beat up my ankles more than usual too.

Where I realized I'd messed up was around 25km. I started feeling the early signs of heat exhaustion like in my final LR with GMP. I got the light feeling like equalizing pressure on a plane or when diving/clearing your ears after coming out the pool, except locked in that clearing-your-ears state.

I knew that probably meant I'd gone out too hard at the start and was getting dehydrated. So in my mind I switched from any target time to just finishing. For the first 20km the 3:45 pacers were just up the road from me but from 20-25k I let them slowly get further and further.

Then around 26km the 4 hour pacers caught up to me and I thought I was getting into a rhythm sticking with them. I was struggling to sort of get in the zone before that because I had no pace group, as the pacers all started at the front and my pen started the race a few minutes after, so I was technically still ahead of the 4 hour pacers.

From 21-28km my average HR was 156, which is my usual high end of zone 2, so I thought I would be okay. However, my rate of perceived effort was going up over those kilometres despite my HR having settled down. I figured it was my body overheating/being dehydrated.

When I reached 29km I decided to let the 4 hour pacing group go and sat down at the aid station after two cups of water and iced myself down a bit.

After 15 mins I felt the heatstroke-like symptoms subside a bit and went to take another cup of water. After drinking it my stomach just didn't feel right, so I went to lean on the center median of the highway feeling nauseous.

A minute or two later I was emptying my guts in the middle of the road. Luckily it was over decently quickly because it was all fluid, but I did notice it had an apple juice-like colour. My carb drinks are colourless and I was only drinking water at that point, so I figured it was stomach acid.

I felt a bit better after that so sipped some water and then tried to carry on. I was able to run for a few hundred metres before I started cramping up. I assumed this was from dumping all the water and electrolytes in my stomach and having cooled down, but when I tried to sip any of my carb drink with electrolytes the taste of it didn't sit right, so I just sipped water from the 250ml soft flask I had with me.

Ended up walking most of the way from 29km to the 31km aid station.

During those 2km/15-20mins I was considering whether to DNF or not. I'd put in a ballot for Osaka marathon and gotten a slot but hadn't paid to lock it in yet, so I was thinking:

• If I cut my losses now I can go straight into training for that without needing to take as much time to recover.
• If I keep going I feel like I'm gonna wreck my ankle for a while too, which will take some time to recover from.
• I don't want to end up 1km from an aid station alone by the side of the road throwing up, dehydrated and cramping alone.

So I decided if my condition wasn't improving I'd DNF.

I reached the 31km aid station and went to the medic tent and asked them what would happen if I decided I wanted to DNF, as I could feel the same nausea and stomach upset I felt before I threw up the first time coming on again.

Shortly after I threw up similarly to the first time, same colour and all, but this time I felt even weaker, so I made the decision to DNF there.

After that they sat me down and I started getting the shivers, so they covered me with a tarp and tried giving me some sports drink and salt water, which I threw up not too long after. This time luckily it was clear and not as much.

They told me that there were ambulances but they were tied up with lots of people earlier on in the course so it could take a while. I asked them if they had any food as I could feel gastric-like symptoms coming on and they said no.

As I sat there the shakes were coming and going and the nausea was getting worse at times, with me feeling a bit delirious and being unable to speak properly or hear what they were saying to me/processing things slowly. I even fell asleep for a bit at one point, I think, despite the volunteer telling me not to sleep.

They also tried taking my pulse and said it was too weak for him to feel anything. I asked the volunteers at the medic tent who were with me if there was any food at this aid station or the next aid station (some of the aid stations had bananas etc) and they said no/they didn't know.

Eventually someone else who was also having similar issues to me, who threw up at km 31 and had decided to DNF, was sitting with me and asked for food. One of the volunteers pulled out bread from one of their bags I think.

This was after around 2 hours waiting at the tent to be taken somewhere after deciding to DNF.

The two of us shared the bread and I was finally able to take on a decent amount of water without feeling sick after putting some solid food in myself, and I was starting to feel better.

At that point if I really had to I could probably have walked the last 10km, but I wasn't sure if my stomach wouldn't act up again and it's also really uncomfortable to walk in the AP4s, so I decided to stick to my decision to DNF.

Finally at around 9am, 2.5 hours after I decided to DNF, a bus showed up and took us to the finish line. Somewhat frustratingly I was a bit stiff but after some walking I was able to jog a short distance mostly feeling okay, which made me think if only I had had some solid food to line my stomach earlier I could potentially have still tried to finish the race.

What I think went wrong

1. I ran too hard when my body wasn't up to it on the day and hung onto my initial goal pace for too long before easing off. This would also have contributed to higher effort making my gastric emptying slower in the beginning.
2. I think my hydration/fueling balance may have contributed to the GI issues. I was taking in 90g carbs/hour and my homemade drink was quite concentrated, so I'm wondering whether I either drank too much water or too little water relative to the amount of carbohydrate I was taking on. From googling about osmolality I probably would have needed ~900ml of water/hour to dilute it adequately, and I should have been close to that, but my stomach couldn't handle it once I'd already paced myself poorly.
3. I still haven't figured out why I was struggling so much with my paces on the day. Can nerves really make that much of a difference? Haze? Poor rest the nights before the race? A combination of all of the above? Could it have been the taper? I was feeling especially flat during the taper etc too.
4. I think if I had been wearing something other than my Adios Pro 4s I could have walked it in/maybe I wouldn't have fatigued as much, I think I'll keep them for HM or shorter distances and pick something else for my next attempt at a FM

This one is the one that's bothering me because for the first two I can plan to be more strict on my pacing and opt for a more conservative fueling plan on race day potentially in future, but I'm not sure what the cause of this third issue is.

Post-race

Also, it felt like the medic tent wasn't adequately prepared/stocked. They didn't have a blanket to keep anyone feeling cold warm, and I literally asked them to use the tarp from the floor before they put that over me.

I'm not sure, but some of the symptoms I was experiencing sounded similar to what I've heard can happen with heat exhaustion/heatstroke. If things had gotten significantly worse, I'm not sure what would have happened given how long it took to get transport. The medic tent initially told me an ambulance would come and pick me up, but after waiting 2.5 hours, it ended up being a bus picking up runners who had chosen to DNF.

There was also no follow-up on my condition when I reached the finish. I just got off the bus and went on my way.

At one point, I was literally about to book an Uber from the road beside the closed highway exit because the ambulance/bus was taking so long. If I'd done that from the start, I probably would have been back at the finish 2-3 hours earlier.

The day after the race, my right leg was also sore from the glutes, hips and hamstrings all the way down to the ankles in a way it never has been before. I suspect some of that may have been from the road camber/banking, although two days out I can feel it getting back to normal but it's definitely worse than usual for my long runs.

What's next?

I'm currently questioning whether I should do Osaka on 28 February.

I have a half marathon on 13 December that I signed up for to accompany a friend. Unfortunately, because I signed up late, I could only get a slot in the "challenge category", where you need to finish under 1:40 for the finisher entitlements. My HM PB is 1:38:04 from a long run with a goal marathon pace during this training block, back when I had a more ambitious 3:15 marathon goal, so I should be able to hit sub-1:40.

What I'm less sure about is whether trying to race a fast half in December and then build straight into another marathon block for Osaka would be too rushed, especially after how this marathon went.

At the moment, I'm leaning towards skipping Osaka and spending some time rebuilding my mileage and racing shorter distances before starting another marathon block. There's definitely some self-doubt creeping in after this race, although I also can't deny that racing somewhere with a nice, cool climate sounds pretty appealing right now.

Alternatively, I'm considering trying my luck with some races in China towards the end of March. Flights are also cheaper for me than Osaka, so that could potentially give me more time to rebuild properly while still giving me another marathon to work towards.

Anyway, I mainly wanted to share this as a cautionary tale. If you set a HR limit for your race, don't ignore it on the day. Slowing down and reassessing your goals is much better than pushing through and ending up with a DNF after months of training. There's always another race.

For anyone who's made it this far, I'd really appreciate any input or advice. In particular, I'm curious what you think might have caused the unusually high HR and poor performance despite the training I'd done, whether my fueling/hydration strategy could have contributed to the GI issues, and whether you'd recommend trying to race again relatively soon or taking a longer break and rebuilding first.

My Strava activity for the Marathon DNF
Strava activity for the last 20 miler for comparison of hr etc

Made with a new race report generator created by u/herumph.

Race Information

• Name: Surabaya Isoplus Marathon
• Date: Oct 4, 2026
• Distance: 42.2 km
• Temperature: 26 degrees - 78.8 fahrenheit
• Humidity: 82%
• Location: Surabaya, Indonesia
• Website: https://isoplusrun.com/
• Strava: https://www.strava.com/activities/20440363582
• Time: 3:17:18

Goals

Goal	Description	Completed?
A	3:15-3:18	Yes
B	3.18-3:22 (Fallback	Yes
C	3:24-3:28 (Hip Issues)	Yes
D	PB (3:37)	Yes

Splits

Kilometer	Time	Pace
0–5 km	23:56	4:47/km
5–10 km	23:40	4:44/km
10–15 km	23:21	4:40/km
15–20 km	23:11	4:38/km
20–25 km	23:04	4:37/km
25–30 km	23:00	4:36/km
30–35 km	22:36	4:31/km
35–40 km	23:32	4:42/km
40–42.x km	10:59	4:52/km

Background

I’ve been a hobby runner since 2017. In 2021 I got injured during the deload week of a HM and didn't run for the next 4.5 years.

In April 2025, I had a hip surgery for hip impingement + labral tear repair. I was able to slowly return to running and in October 2025 my monthly mileage reached 200 km upon return.

I spent the next 6 months building mileage and doing a lot of gym work for my hip rehab. At 14 months post-op I was able to run the 3.37 marathon, however I haven't been able to do any speed-work / LT sessions due to lingering stiffness and sharp pain that would occur whenever I tried to introduce faster stuff in training (8-12 months post-op).

Therefore, since April of this year I have only been running Zone 2.

--

Training

Earlier this year I made goals and schedule for the entire year. My goal was to run a sub 3:10 marathon and only to run 1 marathon for the year. Around February/March when I tried to include faster stuff in training it became obvious that my hips weren't ready for the task and needed more time. Because of this my training plan switched to running High Volume / Zone 2 only and to split the year into B and A marathons.

Between B and A marathons I only had 16 weeks in total. I had to carefully plan how I would recover from the marathon, build a serious block and enter the deload / taper phase. I didn't want to interrupt the progress with the marathon / recovering as my goal was to run higher mileage during the A block.

I got a lot of confidence from the 3.37 marathon where it finally felt like my hips could handle more serious training and speed workouts.

For the A block I wanted to include either 2 MP runs + Half race or 3 MP runs. The schedule on 6-10-12th weeks were to do 13-16-19 km MP runs inside 31 km zone 2 long runs. After the 2nd MP run of 16 km, I had a bit of lingering stiffness and I had to swap the 3rd MP session with a easy long run of 36 km (22 miles) and it was my highest week of 105 km (65 miles).

To summarize the key differences further:

	B block: 3:37	A block: 3:17
Carbs during Race	70 gr per hour	90 gr per hour
Post-Op	14 months	18 months
Speed-work - LT runs	2 painful LT runs early in the block	No
MP Runs	No	Yes - only 2
Peak 4 week average	81.6 km (50.7 miles)	95.2 km (59.1 miles)
Peak 8 week average	80.6 km (50 miles)	90.4 km (56 miles)
Hip Issues during the block	4 weeks consecutive	None
Race Note	Significant pace drop the last 4 km (lost 5 minutes)	Super strong execution

--

Nutrition + Caffeine Abstinence

3 months ago I wrote in this sub: aggressive fueling for the entire block. I'm gonna write another post to summarise the entire 3 months of fueling but I have basically treated every single long run as race nutrition practice and targeted 90 gr carbs per hour. Fueled every single run over 60 minutes regardless of the pace.

I'm someone that's been drinking 2-3 coffees a day for years. For the race I wanted to go through caffeine withdrawal period for 10 days, just so I could get the most out of the caffeinated gels during the race.

-- 

Pre-race

I’ve done the exact 12-10 x bodyweight per kg carb load on Friday and Saturday. Given the heat and humidity, I've targeted 4500 mg sodium on both days.

Had a 1 hour flight from Bali to Surabaya, arrived on Saturday morning and went straight to the race expo to pick up my bib. I booked a hotel 500 meters away from the start line and I can't stress enough how amazing this is.

Race start time was at 4 am, I slept at 10 pm the night before however I woke up at 12.30 and haven't been able to sleep. I assumed I would wake up at 3 am, skip breakfast and only eat 1 gel before the race. However I had unexpected time in the morning so at 2 am I ate 2 x GU basic gels (not caffeine or sodium heavy).

At 2.30, I started watching Modern Family on my phone in bed until 3 am and I slowly started getting dressed to do my warmup outside the hotel.

--

Race

NUTRITION / TEMPERATURE

Race temperature at start was 26 degrees (78 fahrenheit) with 82% humidity. The humidity being at 82% was actually one of the lowest I experienced for a race-day running in SE Asia. I had a proper water, gel, sodium plan for the race which I practiced more than 20 times in training.

For carbs I’ve targeted 90 gr per hour, this is a massive increase from the 70 gr per hour from the last marathon.

First gel was at 30 mins, next at 55 mins followed by every 20 minutes. In total I carried 11 gels, 8 x GU (some sodium heavy, some basic, some caffeine heavy) + 3 x KODA gels (90 mg caffeine each but also 29 gr carbs instead of the 22 of GU).

Took 3 x 215 mg sodium caps planned at 65-105-145 minutes but depending where water station would be around these time marks.

Total caffeine intake was around 440 mg, which is roughly 6 x bodyweight per kg.

--

RACE

This was a small event with roughly 400 marathon finishers compared to the 7000 of the previous one. I chose this race over the bigger Vietnam / Thailand races on the same date, because those are +90% humidity. I was also the only foreigner in the entire race.

My goal in this race was to target 3:18 and depending how my hips would hold up at 20-30 km marks, either to aim low 3:15 or fallback to 3:22 range.

My pacing strategy was to run 6 km at 4.50, 6 km at 4.45 and settle into MP of 4.40 from 12th km. I wanted to have an easy hour of running to allow my hips to settle into the rhythm rather than forcing a pace from the start which could be problematic for my hips.

1st 12 km - For me these KM marks were very important. I had to slowly settle into the race, give an easier hour of running to the hips and biomechanically assess how my hips were doing. There were no issues whatsoever and I slightly had faster splits than planned 4.45 from 6th to 12th km. Around 9-10th km, my HR monitors strap keep falling down below my chest (new strap that I haven't been able to properly adjust for a week). At 12th km it completely fell out of my chest and I had to toss it away.

12th to 20th km - Settled into my planned pace of 4.40, this felt quite easy and I very comfortably started hitting 4.38s with a lot of energy in the legs. This section of the course from 1st to 20th km were pancake flat.

20th to 25th km - This section overall had a slight elevation of 20 meters and an underpass. I actually really enjoy the hills because I train in a hilly area. I ended up dropping 2 others I was running with for 2 km's.

25th to 30th km - This was the return of the exact route of the previous 5km. This meant 20 meters downhill overall and a chance to pick up the pace. Another runner caught up to me and we started running side by side hitting 4.35s the entire way. It was actually so much fun running with another person and sticking to the pace. We didn't share a single word but had an unspoken agreement to run the same 4.35 pace.

30th to 36th km - This was a big pre-race decision making mark to assess how I was doing in the race. I still haven't had a sign of fatigue or slowing down so I started pushing low 4.30s from here. The other runner couldn't run with me anymore and I started running solo until the road merged with the +6 minute joggers from half marathon.

Surprisingly I felt very strong and kept pushing the pace every km while focusing on my nutrition and water stations.

36th to end - At 36th km I would say overall fatigue was at 6/10, however at 39th this all of a sudden became 9/10 fatigue and it was also unbearable. 38th had my last caffeinated energy gel for the race, but it didn't change the reality that was coming a KM later. From 39th, I didn't even look at my splits anymore, I was running to survive and to finish. I kept repeating "only 15 minutes left", "10 minutes left", "just 5 more minutes" and I just continued running without significantly dropping off the pace. I ended up averaging just under 5 minutes for the last 3 km's.

I finished Top 10 in 3:17:18, time that seemed like a miracle when I first ran my marathon 9 years ago. I didn't get any age category awards because awards were only for Indonesians (not a big international race).

--

Post-race

I would have never guessed how strong I would be running and how perfect things went during the race. On my 2nd MP run of 4.40 pace, my pace actually kept dropping to low 4.30's and I'd purposely slow down to 4.40's.

I've been practicing my race-fueling every single week for many months, this felt very natural for me to eat 90 gr carbs per hour during the race and keep up with the nutrition side of things.

I've put in a serious amount of work for the entire year, first with the post-op rehab and after with the mileage. It felt incredible to finally run the time and the strategy I planned.

Now I sort of have a 2 months holiday (mandatory life obligations) and will return to proper training from January. I don't think I will run a marathon in 2027, but I will most likely be aiming around a sub 3 marathon on the next one. Next years focus is entirely going to be Half Marathons and a lot of gym work and hopefully start running speed sessions.

Made with a new race report generator created by u/herumph.