Post Script: Half Ironman Triathlon, Endurance Sports, Diabetes and Ketones

Having completed the Wild Boar Half Ironman, been on a DAFNE course and had time to reflect on the event (oops, almost wrote ‘race’ then, LOL) I’ve come to the conclusion that I probably developed ketones during it as my sugar levels were too high, I felt sick for much of it, got stomach pain during the run and my performance was ultimately affected – a result of not taking any insulin that day.

This article is my version of endurance sports and diabetes as a type 1 diabetic and my experience during the event. This is a useful article on ketones.

I suppose the easy diagnosis is to put these symptoms down to just being in a long triathlon and I’m going to feel tired and perhaps not terribly great no matter what, but diabetics are saddled with complications which shouldn’t be dismissed and as my sugar level gradually came down I did feel considerably better.

During training I wouldn’t take any insulin if I was about to exercise, regardless of the duration or intensity. Depending on what my sugar level was I might take a gel or have a bowl of cereal or piece of toast before heading out in order to keep it sufficiently high. My sugar level would always come down and I’d take gels, Dextro tablets and sports drinks to keep it up – my sugar level that is 😉

It mystified me why my sugar level remained so high but I put it down to carbo loading the week before, perhaps more carbs than usual immediately prior to the event and the excitement (nerves) of it all. My body was loaded! Expecting my sugar level to come down I didn’t take any insulin. A small shot during the bike ride would have done the trick I think.

Low blood glucose reading

Going on the DAFNE course taught me about the physiology of the body and ketones. I’m now on an insulin pump (about which I’ll write later) and wear it the whole time. Prior to the event ideally I’d exercise first thing in the morning or after work. For the latter there’d be little insulin washing around inside me as my last shot would have been at lunch time and it lasts for only four hours in your body. If I was exercising soon after a meal, e.g. breakfast, I’d usually head out an hour later with no insulin. Now, to address ketones, if I’m heading out after a meal I’ll take half my usual dose of insulin and wearing my pump I reduce the the background dose by 50%.

Zipvit gelHowever this now means I’m forever going low which is not fun. Went out for a bike ride yesterday after brekky and half insulin dose. My sugar level caved in: I went down to 1.2 (21.6)! Yikes! The lowest I’ve ever been. I felt low, but not THAT low. I thought I should be clinically dead at that level. Had a gel quickly and two minutes later was 4.2 so I think it might have been an anomaly as surely it takes time for the glucose to get into your bloodstream. I’d planned a 113km hilly ride but after 1 1/2 hours I’d had four gels already – big gels, 60ml, each with 51g of carbs in (85g per 100ml) – and half a pack of Dextro tabs. I’d taken six gels with me and could see myself running out if I carried on like this so I cut it short, turned my background insulin down to 20% and headed home ending up doing just 64kms.

The same thing happened on a run recently. I have a 20km hilly route I do. Usually takes just under two hours. Kept going low and it took me 2:30.

Anyway, my point is that taking insulin prior to exercise just makes my sugar level plummet so I think I’ll go back to my old regime of taking none at all if I’ve just eaten and maybe reduce my background a little more still. If my sugar level seems to be remaining high I’ll just take a small shot to sort it out.