I’m going to talk about mountain biking, but this probably fits any activity with sustained high intensity exercise.
My 13yo son loves mountain biking, but we’re still grappling with keeping his BG levels in check. He currently uses a Tandem t:slim X2 + Dexcom G6 with Control IQ.
This scenario is common enough to be frustrating:
- Have breakfast & bolus for the calculated carbs.
- 1-2 hours get ready for the ride, pick-up friends, drive to trailhead.
- Start riding uphill (1 hour climb is pretty standard, but can be 2+ hours as we live next to a mountain range).
- BG levels plummet & we end up a quarter or halfway through the climb trying to get BG levels up via fruit juice/ sweets etc.
- Double the amount of time it takes to get to the top of the hill.
- Often overshoot BG after the ride into a stubborn high.
We’re doing the following:
- Turning “Exercise Mode” on around breakfast time.
- Pre-loading a 13 carb juice 30 minutes before the ride.
- Trying for lower carb breakfasts.
The lower carb breakfasts are the most successful, but it doesn’t take much for a breakfast to be carby - even a glass of milk is 9gm of carb.
Also - when we get to the top of the downhill, the nature of the exercise changes completely. We go from a lot of physical exertion cycling uphill to a mixture of mental & physical effort riding down again. There’s not much pedalling, but physical effort is required to keep off the seat & pilot the bike over roots/ rocks/ jumps/ chutes etc. - with extra adrenaline on top!
A common ratio is 60 minutes uphill to 30 minutes downhill.
I’ve heard of adult T1D mountain bikers not bolus at all for breakfast before a ride - is that wise?
If anyone has any tips or tricks about this sort of situation, please let me know!
