Pump it up - Adventures of a type 1 triathlete with insulin pump
Pump it up - Adventures of a type 1 triathlete with insulin pump
Please visit my new blog here: Pump it up - Adventures of a type 1 triathlete with insulin pump

Diagnosed at the age of 5, I have been a type 1 Diabetic for over 29 years; being on an insulin pump for 11 years now. I took up triathlon in 2011 and am hooked ever since! Being diabetic doesn't stop me from doing what I love - swimming, cycling and running!

Cycling in the mountains and avoiding the glucose uphill or downhill ride

Eva29by Eva29Jul 29th 2013
The one thing I have learnt about my Diabetes over the past 26 years of living with it is that being flexible and not afraid of making gradual changes is key to manage it well. A great example and reminder of that was my week of cycling in the stunning Pyrenees as part of a training camp.

With no experience of cycling in the real mountains (there are only little humps around where I live), I had no idea what to expect both from my legs (would they last for a week?) and also from my blood sugar (how would it behave?).

Over the past two years I have gained considerable experience in managing blood sugar levels on the bike up to 6 or 7 hours but yet the training camp in the Pyrenees was a very different challenge: Whilst I pursued the same strategy of reducing my insulin basal rate to 50% from up to one hour before heading out on the bike and applying a similar nutrition strategy that I knew would work for long endurance sessions on the bike, I had to make considerable adjustments from the minute I reached the top of the mountain and taking a break or when going on the long downhill descents.

For the first two days of cycling I needed to understand what impact the extended duration of climbing up the mountains had on my body and thus sugar levels. Whilst we would usually cycle anywhere from 20-40km in the valleys to get to the bottom of the first climb we had planned to do, I didn't need to change anything in terms of basal rate and nutrition because it pretty much resembled the sort of cycling through countryside that I was used to from training and racing. After day two when I kept going into a hypo about 2-3 hours after my normal breakfast, I adjusted back to my race breakfast which meant cutting down on carbs to avoid injecting A LOT of insulin (which was the reason for my hypos). I can cope much better with small breakfast when I know I will be training pretty much soon afterwards. Therefore, the less insulin I need to inject, the easier it is for me to avoid hypos resulting from breakfast injections. Even a reduced rate of bolus insulin for my breakfast doesn't work most times because it sends sugar levels sky high which makes me feel unwell and lethargic.
So, by adjusting to my race breakfast mainly in form of protein, I was able to stop hypos from the breakfast bolus.

On the long climbs (10-20km) during the first few days I noticed that my blood sugar started rising as soon as I reached the summit and even more so when I descended. I found it pretty difficult as naturally people wanted to stop, take a break, have a bite to eat etc. but I knew that stopping and taking on food would just make my sugar levels rise even more. Often I ended up with a higher sugar level after stopping and descending than at the start of the actual climb. I realised that the strategy that worked fine for me on undulating or flat terrain in training and racing didn't work well in the mountains.

I was lucky enough to have a CGM (Continuous Glucose Monitor) connected to me which measured my glucose levels 24/7 and transferred the result to my insulin pump. This helped me to see trends in rising or falling sugar levels. I estimated that the reduced basal rate and nutrition strategy worked usually for half way up a 10-12km climb or 2/3rd of any longer climbs (more than 15km) so decided to test it out and stop taking on small amounts of nutrition (usually 1-2 pieces of liquorice or one bite of muesli bar) and see how my sugar level was when I got to the top: I tested this for the first time climbing the Tourmalet and to my surprise it worked! I got to the top after climbing 20km with a sugar level of 86mg/dl (4.7mmol/l) (and hadn't gone into a hypo.
Yet I still experienced problems after that: When I descended the Tourmalet, again, my blood sugar had risen from below 100 (5.5) to 186mg/dl (10.3mmol/l) without me taking on any food!
To tackle the problem of rising levels after reaching the top, I decided the next day to have the pump back running on 100% basal rate the minute I reached the summit (since we usually would have a 20-30 min break) and depending on the length of the stop I would sometimes even inject a little booster of 0.5 units.
Most diabetics can probably sympathise with me when I say that it scared me to inject insulin boosters. It is pretty counterintuitive to inject and increase basal rate when you are actually still exercising. However, I needed to test it out despite the risk of potentially going hypo after the descend. Much to my relief no sign of a hypo on the descend and 40-60km cycle homebound! I sometimes ran my basal rate to 80% when on the home stretch.
Ironically, the more days I had spent in the saddle, the better I felt because I had worked out how I needed to manage my glucose levels and nutrition (and to some extend the pace I needed to ride at) to keep me going for long.
By day 4 I had successfully turned the single strategy I had learnt in the past for racing and training in undulating or flat terrain into a 3-fold strategy which worked:

That day we cycled a total of about 140km with over 2000 metres of climbing. The first climb of the day was the Port the Bales, a stunning 19km climb with the first half at a nice 4-6% gradient and the latter half a little more to 7-9%. I started the climb with 89mg/dl (4.9mmol/l) and reached the top with 101 (5.6). Spending only a short while on top we descend for about 10km to the bottom of the second climb: The Col de Peyresourde, a 15km climb with an average of 6-7% and the steepest section around 9.5%. I managed to keep levels stable at that level and reached the top of the Peyresourde with 96mg/dl (5.3mmol/l).

This is the profile of the day taken from my CGM:
Cycling in the mountains and avoiding the glucose uphill or downhill ride
You can see how stable it was during the ride from 8:30 to about 16:00. The little red squares indicate where I tested glucose levels manually to calibrate the CGM, the small green triangles indicate where I ate carbohydrates (and subsequently injected bolus): A clear rise in glucose levels reflects this (mainly breakfast and dinner). The green belt is the area that I set as normal: 80mg/dl to 200mg/dl (4.4 to 11.1mmol/l) The CGM would give me a warning if the levels dropped lower than 80 or would rise above 200.

The experience of cycling in the Pyrenees has been hugely helpful for me and to a non-Diabetic it may sound like an awful lot to manage and work out in terms of glucose and insulin. It has been challenging at times for me; and a little scary too when I wasn't sure if my plans would work or not and I could end up in a hypo or going hyper. Despite this, it is incredibly rewarding when you get to the end of a long day of cycling and have managed to follow the footsteps of the Tour de France (albeit much slower than the pros!) with no single hypo or any other hiccup. To me that is what counts.
It reminded me again that in order to have stable glucose levels, I need to remain flexible and adapt insulin and nutrition to the demands that the environment I am in throws at me.
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