I've just completed my first marathon last sunday. It was pretty much a global disaster. I started cramping up at the 18km (11mile) mark before completely comming to a halt at km 31 (19.5 miles). I finished in around 5hours. Way beyond the 4h mark which was (based on my training) calculated as expected finishing time (=my long run training tempo). In the end I wasn't tired(=which frustrated me), I just had cramps all over the place.

As I trained thoroughly for 6 months completing no less then 7 times a 20milers without feeling any exhaustion/cramps.

One of the reasons of my failure was the warm day I believe (next to me being nervous). It was 26°C (78,8 F) at its warmest. And I tend to fail/cramp up during warmer weather. I've tried pretty much every trick in the book:

  • Drinking extra during the run
  • Drinking sports-drinks or any electrolyte rich drink which I used in training
  • Taking electrolyte/salt-rich tablets during the run
  • Antacid tablets
  • ...

The marathon itself was at a near-coastal town (Bruges) and 100% on paved roads. I live some 40km from the town and experience the same climate/temperatures.

So I was wondering if there are any training techniques/tips which might help my body perform better during warmer days? Does any had the same problem & how did they overcome it?

Sidenotes: before any mentions under-training

  • Pre marathon Training load: around 65k/week (=40miles)
  • Number of 20milers: 7 in the 2,5 months leading up to the marathon. all without cramps or fatigue.
  • Preparation Distance(6 months): 1800k (1125 miles)

My trainingscheme up to the marathon

  • Monday: An Easy 10 to 12k at 5'45"/km (hr below Aerobic threshold)
  • Tuesday: 15k with 6 times a mile at 5'/km (hr on the border between extensive/intensive workout) (rest 400m at 6'/km)
  • Wednesday: Off or Crosstraining (40km on the bike Max)
  • Thursday: 12k with either 4 mile repeats (pace like tuesday) or 6 times 4minutes at 4'20"/km (hr on the lactate treshhold) & rest 2minutes at 6'15"km
  • Friday: Off
  • Saterday: Long Run: 22 to 30 km at 5'45" (hr below Aerobic threshold)
  • Sunday: off or some light cycling

The marathon

  • Pace from km0 to km18 (first cramps): 5'55"/km (HR above aerobic threshold somehow). Was following the 4h15' flag.
  • Pace from km18 to km31 (reduced speed to compensate for the cramps): 6'10"/km (HR around aerobic threshold)

2 Answers 2


I can't state that the temperature was your problem, but it's the title of the question so I'm going to answer that specifically.

Someone who is acclimated to heat will have numerous physiological advantages over someone who is not:

  • They will sweat out less electrolytes, particularly salt.
  • They will sweat earlier, starting heat regulation early on.
  • They will not vasoconstrict as much, keeping blood pressure lower, keeping perfusion higher.

There are other advantages, but clearly those alone are enough to show the importance of being "heat acclimated". Losing electrolytes wreaks mayhem throughout your body, affecting cellular activity when it's needed most. Slower thermal regulation causes your temperature to flare up, exacerbating the issue. And hyperthermia triggers vasoconstriction which reduces blood flow to skeletal muscles, your heart, your lungs, and every cell in your body.

14 days is the generally accepted period of heat acclimation, with the first 3-5 being quite important in their own right. It's been noted that there is a difference in adaptation between high and low humidity environments as well, pertaining to heat.

A reality of athletics is that you need to train for the event's conditions. I live at 8,000 feet and we have plenty of trails and lakes above 10,000 feet so high altitude training is just how we live. When people from sea level come up here they are severely impacted, and there's just no way to train hard enough to combat that other than real altitude acclimating.

Similar to the biological changes from heat acclimation, altitude includes the increased production of EPO, a hormone that triggers red blood cell production. At 10,000 feet, after acclimating, you will simply have more red blood cells. I bring it up to make it clear that you really cannot train hard enough at sea level, or in a cold environment in your case, to makeup for the biology.

You'll need to ask yourself how important any given race is to you, and knowing conditions like altitude and temperature, are you going to put yourself on even footing with the folks conditioned to those environments?

  • 1
    Eric Kaufman, interesting point of view. Though the marathon was near my hometown (40km) at sea level. i'll add this the question. Though +1 for the interesting reading material.
    – User999999
    Commented Oct 17, 2017 at 15:39
  • Hopefully I made the point that in your case it could have been the heat, but regardless it's a biological adaptation that (if it was the heat at all, and not diet, training, other illness, etc) needs to be considered.
    – Eric
    Commented Oct 17, 2017 at 15:41
  • 1
    Yes. I completely understand you :-) . Thank you for your information. Though it feels like I will have a lot of reading Up to do, to get fully familiar with this theme.
    – User999999
    Commented Oct 17, 2017 at 15:46
  • Though perhaps a small question, if I may: Sweating a lot more then a standard person is not necessary a bad thing? Until now I believed that my extensive sweating was the reason my body couldn't adapt to warmer temperatures.
    – User999999
    Commented Oct 18, 2017 at 10:18
  • @User999999 no, heavy sweating is an adaptation. I have had the same thing, esp as I live in a hot climate, and run up to 1/2 marathons in 80+ Fahrenheit
    – JohnP
    Commented Oct 18, 2017 at 14:19

Note: Much of this is taken from my answer here, as I believe they are similar situations. However, I would disregard the pacing, as I ran your pace through the Macmillan calculator, and I don't see anything indicating that your pace was too ambitious.

  • Climate: Many times people underestimate the effect that climate has on an endurance event. Either much hotter or cooler, or differences in humidity can wreak havoc on the race.
  • Elevation: Going either up or down drastically can have an effect on the race. Going down is usually preferable, people have much greater impact going from low to high.
  • In race nutrition: If you don't train with it, don't do it on race day. Too often people either drink/eat way more or less than they do during a training. This can have a drastic impact on race execution.
  • Pre race nutrition: Again, if you don't do it in training, don't do it on race day. See above.
  • Pacing: This is another very common one for people to miss when racing. They get out there, they are amped up and excited, and they feel good, so they push a little more than they were planning. Even a few seconds per mile faster at the beginning can put you in a huge hole by the end of the race. Even if you feel awesome, wait until after 1/2 way through a race before you think about deviating from your plan.
  • Terrain: Same as pacing. If the terrain is different from where you train, you either need to travel to train occasionally under the same terrain conditions, or be prepared to slow your pace accordingly.

Now for the cramping, Erik addressed that rather nicely, so I would only add that for myself (n=1), I find that I tend to cramp if I am underprepared or I push too hard for the training that I have put in.

The one thing that does concern ;me about your training is the volume and frequency. You would be much better off doing the same amount of training, but spread out through the week in 5-7 workouts rather than lumped into 4 days with 50% of it on one day. I would keep the speedwork, shift some of the distance from your longest run to an off day and add a day. Ideally I would also increase the weekly mileage by 50% over time, but that is up to you. Most high level distance runners are somewhere in the 85-120 miles per week range.


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