Life is all about backup – especially when cycling with type-1 diabetes and an insulin pump!
Mario and I headed to Iona Beach on our bikes this morning. It’s a great 75 km bike ride because:
- It’s got all the scenery – we had wide expanses of blue water and green farm fields next to us for a good portion of the ride. Today, I saw at least three hawks – one that swooped in and grabbed some breakfast before flying away. I also counted seven herons hanging in the shallow waters of the Strait of Georgia, as we were approaching the beach. Once, I even saw what looked to be a Scottish Highland Cow sunbathing on the front lawn of a very large farmhouse.
- It’s a predominantly flat ride, which means my average speed gets a nice boost up. There’s some decent resistance with the headwinds, but if you’re lucky, at some point in the ride, you’ll get a strong tailwind to speed you up even more.
Today, we got the tailwind!
The Ride Was Great. The Blood Sugars Were Not.
Although the destination for the ride was great, my type-1 diabetes on the ride was challenged.
After last week’s cycling adventure, I changed a few of my strategies up. I didn’t put a lower basal profile on prior to going on the ride, and I only started activity mode about 45 minutes before the start of the ride. Just prior to leaving, my blood sugars were 7.7 mmol/L. I took in 2 Swedish Fish, and started pedalling.
Similar to last week, I was eating every 20 minutes. However, I quickly learned my 1-2 gummies wasn’t going to be enough. I was handfuling those suckers into my mouth after a while just to keep my blood sugars afloat. About 45 minutes in, I turned on the lower profile basal, but it still wasn’t enough. I swear I ate 45-60 grams worth of candy carbs, plus another 15-20 grams in RxBars.
The first half of the ride my blood sugars hovered in the 5s. I was taking in a lot of carbs and my pump was suspending insulin. When we stopped at the coffee shop, though, and I sipped on my hot matcha, my body started digesting those earlier carbs more rapidly. Before I knew it, my pump had delivered 0.86 units of insulin. The problem was that I was no longer burning through carbs at cycling intensity, but my pump was still responding to the rise in glucose. And because of that, for the remainder of the ride, I was also having to suck back gummies.
D’oh!
Dexcom G7 Fails and Backup Prevails
My Dexcom G7 sensor also had a few challenges.
I had it inserted into the back of my thigh. That was probably mistake number 1!
A few years ago, whenever I had my Dexcom in my legs on a ride, I would frequently lose connection, or there would be a sensor error. This never happened on other rides when I had the sensor in my arms or lower back – just in my thighs. I figured it had something to do with the lycra compression from my bike shorts, and so I stopped putting them in my legs during cycling season.
Clearly I forgot about that rule, because here I was this entire ride fighting random Dexcom shut offs.
For those of you who don’t know, when a person is on an automated insulin delivery system (AID) insulin pump, like I am, the insulin pump relies on that continued communication with the continuous glucose monitor (G7) in order to function adequately.
I did have my old-school finger prick glucometre, which I carry for all my rides, so at least I had some idea of what my blood sugars were doing when the sensors failed. But for AID, the finger pricks just don’t cut it.
Today’s T1D Ride Stats:
- 7 am: Breakfast BG 6.0 mmol/L — insulin dosed 1.88 units
- 8 am: Start exercise mode
- 8:45 am: Ride starts — BG 7.7 mmol/L. Insulin on board 0.48 units. Ate 2 Swedish Fish
- 9:30 am: BG 5.5 mmol/L — switched to activity basal profile with a 60% reduced basal and more conservative correction factor
- 10:15 am: Arrive at Iona Beach — BG 5.0 mmol/L
- 11:30 am: Arrive at coffee shop — BG on the meter 8.6 mmol/L
- 12 pm: Auto correction of 0.86 units
- 1 pm: Ride ends — BG 4.8 mmol/L
- Distance: 74 km
- Average pace: 24 km
- Fuel: mostly every 15-20 minutes as mentioned above
Post Ride Lunch Strategy: my lunch had ~45 grams carbs in it. For the insulin dose, I topped up with 15 grams ghost carbs. This dosing strategy was more conservative than what I usually do for my Peloton morning long rides, and I was worried that I would endure a spike given all the auto suspends and high sugar gummies that went into me. But based on last week’s findings, I opted to be more conservative, and it worked. No post ride spike for me 🙂
Next Steps:
Strategy I may try next time:
I like the automated insulin pump for physical activity, but it does have some faults as seen here today.
The next ride I go on where I plan to stop at a coffee shop, depending on what my blood sugars are doing, I may suspend my insulin for the duration of the stop to prevent an unintended auto over correction. That way, if needed, I can give myself a mini bolus that doesn’t result in having to eat the entire candy store to keep my blood sugars afloat!
