Cramp during Marathon - Help and advice please

Hi All,
I have just had to pull out of my second marathon this year with cramp at the 12 mile mark. This happened to me in a marathon in May this year although I managed to get to the 15 mile mark before pulling out. My BG when the cramp first started this time was around 105 so I know having a low wasn’t the cause.

I have run 2 successful marathons previously since being diagnosed with T1.

Some background :- I am a 50 yr old T1 lada, diagnosed when I was 46, I am on a low carb high fat diet, I take Magnesium and Potassium vitamin supplements, I am on MDI insulin.

I have successfully completed training runs to the 20 mile mark this year without getting cramp. I usually do my training runs in the early morning starting at 4 am so I get finished before work. I usually do my training runs on an empty stomach and I will eat bananas and drink water during my runs.

Today’s marathon started at 6:10 am and it was warmer than it has been on my training runs. I also had breakfast about 2 hours before the race started.

Any advice or suggestions in overcoming this cramp issue would be welcomed. If you need more info just ask.


I know of a few reasons you cramp during a marathon assuming you have trained. Magnesium, Sodium and water
Are you using electrolyte salt tick capsules? Are you Hydrated, do you take enough gels during your marathon (every 45 minutes to an hour)?
I cramped during one of my marathons (my 4th) and was told it was probably a lack of salt (wasn’t taking sodium at the time) - I broke my record but slowed down for the last 6 miles.
I also eat a low carb (paleo) diet, but I use GU gels during my runs and do try to carb load a bit before a marathon (I eat about 60-80g normally so I try to get to 200g).

I think I’d had 15-20 Gatorades, chased with water, at the race I ran recently and had horrible cramping about the 1/2 way point, like you are describing. Afterwards, I got some CES graduated compression socks and will see how I do next time, probably in May. I think I may have run a bit too fast out of the gate and it was a bit warmer than it had been.

Hi Mike,
Thanks for you suggestions. During the race I drank an isotronic drink ( Powerade ) at every water stop so I should have been well hydrated. We cannot get Salt caps here in NZ so that is why I was taking the vitamin suppliments.

Hi, Bruce,
Electrolyte capsules are ideal, but just plain salt is good. I have friends who just use table salt.
When you had to drop out, were you crusted with salt from your sweat? That would be another strong indicator of where the problem was.
If you can, try to get some long runs in on your days off during the heat of the day, both for conditioning, and to see how your body reacts.
Another sign that your problem was electrolyte deficiency would be if you were to try some salt, and it tasted great, not salty.
Good luck in your next marathon!

I had terrible cramping during my marathon in Denver on Oct 9. I was able to push thru to the end but was really miserable. I’m preparing for my second marathon and plan on increasing my electrolyte intake leading up to and during the race. I’m using nuun sugarfree electrolyte tablets and carrying salt packets (from any fast food restaurant) with me for the race. I’m running the NYC marathon this sunday. I’ll let you know how it goes!

Hi Jerry,
Yes I was crusted with salt when I pulled out. This is normal for me during my training runs as well. I didn’t have any salty foods to eat after my run. I will have to try this after a training run and see how the salt tastes.

Hi Brian,
I would be very interested to hear how you go with the salt and electrolytes during the NYC marathon.

Hi AcidRock23,
I have not heard of CES graduated compression socks, how do they work ?

Bruce my electrolyte strategy for the race worked perfectly! Day before the race I used 3 nuun drink tablets. Morning of the race I used 2 and ate a packet of salt for good measure. I had no cramping at all and had a great race! Good luck with your future races!

I've never had any real cramping problems except when I go too hard for my fitness. I've read some interesting studies from exercise physiologists that suggest cramping due to electrolyte depletion during an event is unlikely, but at the same time the anecdotal evidence in favor of electrolyte supplements is bountiful. Certainly they can't hurt!

Can't you get NUUN or other tablets online?

Hi Bruce,

I'm very similar in a lot of ways. I ran my first marathon back in October and have the same issue. I finished it just under 6 hours. But the cramps started at mile 12 and got worse till all I could do was walk.

Afterwards I did some serious searching to see what the issue might be. First off I was taking Magnesium and Potassium as well along with a good multi vitamin. I also take a low doses of Pravistatin and lisinipril.

I'm a heavy sweater. In fact when I was at the finish line my family noticed all this white crystal stuff all over me. It was salt dried from my sweat all over my body.

I read about salt and calcium being the too that might be the issue. Also when I'be had my quarterly labs done my sodium has always been on the low side. So I purchased a product called Thermo Tabs. I take one in the morning and one at bedtime. If I know I'm also going to be running for a long time I'll take another before I race then one for every 6-7 miles. Also for the calcium I take a Tums in the afternoon. I don't take a Tums in the morning because it can block vitamin absorption.

Since then all my night cramps I've had most of my live in the calves have almost totally disappeared. I only have issue if I've done a lot of running that day.

I've not tested it yet on a marathon. But I'm signed up to run a 1/2 on New Years day. So this will be for me anyway a great test as I was just starting to cramp up at mile 12. Good luck.