Cycling with bouncing blood sugars

I have taken up cycling this year and train reasonably hard to increase my speed etc. The problem I am experiencing is that within 20 mins or so my blood sugars plummet only to be met with a liver dump which sends me back up to around 8 to 11. I try to start my ride around 10 but to be honest it doesn't seem to matter what number I start on, the same thing happens. I am finding around the 1hr 20 mark I am tiring and falling back from the group. There is probably part fitness issues with that but I am trying to find if the liver dump is causing some of tiredness problems. Most sources say not to eat for the first hour of riding but I wonder if any Diabetics have different advice? I am on Basal Bolus and reduce my basal the evening before by 25% when I know I am riding. Bolus I try to eradicate at least 4 hrs before the ride

Any advice appreciated

I haven't ridden much this year but I would generally eat a cliff bar with no bolus if I knew I was riding for an hour or more on my way to the ride location and reduce my basal by 50% once I arrived for the ride duration + an additional 30 minutes to an hour after completion. Had pretty good success with that routine but I would also carry some type of gel as well in case of higher intensity group ride or longer duration for supplemental energy, I've been using Chocolate #9 since being diagnosed, prior to that I just bought whatever I felt like.

Biking at any decent speed drops my BG like a rock too. I try to cut insulin left and right. My perfered method is to bike after a meal and cut out a good amount of my meal bolus. For instance my pump suggest 4 units for dinner I may lower the dose to 2 or 2.5 units. Then I plan to leave as my BG starts edging up.

If I was going for a longer ride I would do a temporary basal rate (if your pumping)also or possibly by itself. Temp basals can be difficult for me because it seems to take a lot of planning and remembering. First off you need to get a resonable amount of insulin to cut. If you are riding fast and hard you may want to consider 55-70% of your normal basal and adjust from there as needed. Next, an hour before you plan to ride is when you should set your temp basal. Ideally your BG will just be starting to rise when you get on your bike. Next you will need to guess how long your temp basal should last. This will depend on how long you ride and if you have a lot of hypos after riding.

I bring lots of hypo treatments with me and test every 20 minutes or less.

Further info
I am on MDI
HBA1c 5.9

Doc will not put me forward for a pump as apparently I have to good control to get approved.
Experiencing highs now on the days I don’t ride even though I go back to my normal 14 units of levimir on those days

I love cycling but only have time right now to go to work and back. Its a 32 mile round trip, so a decent ride and I push it hard(try to avg about 19 mph). Since im only on the bike for about 50 min at a time, I don't have to reduce my basal or eat anything to raise my blood sugar. The cortisol I release from the intense exercise will keep my blood sugars up for the 50 min im on the bike. When I have done longer rides in the past, I would need to eat something at the 1 hr mark or I would start to drop fast.
I should also note that Ive only been a t1d for about 2 yrs with tight control, so I am probably still in the honeymoon stage.
I always make sure I have some kind of candy within reach while I'm on the bike just in case.

that stinks. my dr pushed me to go on the pump almost as soon as I was diagnosed. I think I was only on MDI for about 3 months. My A1c usually hovers around 5.5 with the pump. You should find a different dr, because pumps are much better than MDI imo!

Kevin - I used to bicycle frequently and had to continuously guard against hypoglycemia. I now primarily walk for my exercise.

I just read about this study published in 2012 in Diabetes Care entitled, "Effects of performing resistance exercise before versus after aerobic exercise on glycemia in type 1 diabetes." This link contains the results of several studies. Look on page S-98 for the cited study.

The study concludes, "Performing resistance training before aerobic exercise, rather than the reverse, results in attenuation in the decline in glucose levels that is typically seen with exercise. It also invokes fewer exercise-associated hypoglycemic events and requires less carbohydrate supplementation during the activity."

I've read many individuals' claims that blood glucose rises during and after strength training. I've never tried this myself but it certainly seems worthy of personal experimentation.

I like cycling but it's not my main activity as it's sort of cross training for my main activity of running. I think I rode 20 miles at 20 mph once, but sort of cheated as I cut through town on the parade route on Labor Day. I don't ride much more than 20-30 miles, although occasionally I'll ride out to 40. I keep signing up for these marathons that sort of are time sinks. My plan for rides is to bring Gatorade for fuel and try to have relatively flat bg and just drink Gatorade every 5-6 miles. I use the powder b/c it's 1) cheaper and 2) can be mixed to different concentrations. If it's a longer ride, I put in more carbs. If cutting your basal doesn't work, it might be useful to split your basal dose and cut the one that's "on board" at ride time a bit more than 25%? for long runs, like 10 miles, I usually am doing like a 30-40% basal rate unless I'm running high for some reason. I also "cheat" with a CGM and pump which sort of makes it easier to keep an eye on things. I like to eat about 2 hours before long runs (all of mine are with a group in the AM...) to try to clear out the IOB before I blast off. I do a test before I start and have some extra carbs to cover it. I am not a huge fan of various sorts of Clif/ Power Bars for quick adjustments as they seem to hit rather slowly and I always see spikes 2 hours after I eat them, but maybe that's just me. If I need carbs, I want them *now*.