Reducing Insulin Doses for Long Runs

I signed up for a 30K (18.75 miles) off road race a couple months ago. At the time it seemed like a good idea, but I have been nervous about it for the last couple weeks and was not at all sure I would complete the race.

I had originally planned to complete two 19 – 20 mile runs before the race knowing that this race would be harder than a 18.75 mile run in the park. But a stomach virus slowed me down, and the long runs I did complete made me even more nervous since I suffered mid run lows and high heart rates.

So I decided I was going to change a few things for this race. The first, following a short experiment, was that I was going to use energy gels during the race, and the second was that I would use much less long acting insulin the night before the race (Lantus), hoping that this would help me keep my BS levels up during the race and keep me from any nighttime lows which may be the cause of my heart rate problems.

I have been reducing the amount of insulin I take at night for the last week and a half. I went from 18 units to 16 then 14 and then 13. I haven’t seen huge changes in morning sugars but I do think they are a bit higher. I think I need more time on the new dose to see if it’s right or not.

The night before the race I decided to take 8 units of insulin. I knew I would probably wake up a little high but I wanted to make sure I didn’t experience nighttime lows (in case they are connected to my heart rate problems) or mid run lows.

I woke up at 4:00am on race day and checked my BS. It was 156. It was higher than I would normally like but not so bad for prerace blood sugar. I had an hour to prepare myself to go and a one hour drive to the race. I didn’t eat anything before the race (only two cups of black coffee and a lot of water).

I checked my BS again before the race (three hours after waking up). It was 166 (is it only me, or does driving increase BS levels?). I decided I wasn’t going to check my BS during the race itself and hoped I would be ok.

The race itself was difficult. It was hilly and off road – two things a flat city runner is not used to.

I had my first energy gel after 15 minutes and then again every half hour. I didn’t suffer from nausea and felt fine throughout the race (except for feeling like I was about to collapse for the last 2 miles, but that is not unusual). As I crossed the finish line someone handed me a cup of water which tasted a little sweet to me so I wasn’t surprised my BS was 190 at the end of the race, 15 minutes after my last gel. I checked again half an hour later and I was back down to 132.

I don’t know if it is just a coincidence or if lowering my Lantus dose worked, but my heart rate was fine throughout the race.

I can also say that I have a new personal record for 30K – 2:52:47 – but that is only because I’ve never taken part in a 30K race before.