Hi TNTRI!

Yes, I have experienced what you are describing many times on the bike, run and swim - BGs running low during the exercise, but then spiking up as soon as I stop, especially if I've eaten a lot of food toward the end of the workout. One endocrinologist told me it was because the body slows down digesting food during exercise, as part of the fight or flight response, and then starts up again when you stop working out. This doesn't make a ton of sense to me, because our body is obviously able to metabolize gels and sugars pretty quickly while exercising, but I'm not an expert.

Some tips on how to prevent the situation you described: To start, I would avoid the big plummet in your BGs which caused you to eat a bunch of food during the ride. Even though your blood sugar was 150 at the start of the ride, you probably had a decent amount of insulin on board either from your basal or a recent bolus, that caused you to plummet so fast. My BG also plummets very quickly whenever I start biking, so I avoid it by turning down my basal rate down by 60-80% an hour or two before my ride, which helps smooth out the drop. If you aren't on an insulin pump yet, the best solution is probably to eat a gel or bar 5-10 mins before your ride, so that it starts digesting and just barely begins bringing up your BG, but doesn't have time to spike it up super high before you get on the bike.

I would also recommend setting your CGM to alarm whenever you start to drop, so that you can eat something on the bike before your blood sugars get to 70 or lower. I have found that when I am dropping on the bike and I don't eat before I am below 90, its already too late and I'm going to get low and have to stop. And if you are getting low readings on the bike, its best to stop for 5-10 mins and wait for your sugars to come back up before getting back on, because continuing to cycle will just keep driving them down.

I hope this helps, good luck! It gets easier as you learn how your body reacts to exercise!

Hey thanks for the response. Since writing that post I have gotten switched to an insulin pump. I’ve only ridden a handful of times since then cause I actually ordered a new bike and sold my old one am still waiting on the new bike to arrive so I haven’t tested things out yet. I have ran a handful of times recently though and am still experiencing the same issues. I make sure the numbers look good before starting. I have even taken a gel and then started. Switch the pump into sport mode and then go for a leisurely 3 mile run. Typically by the time I am done it has already dropped.

Insulin typically takes 15 minutes to start working in the body, but hangs around for another 2-3 hours. I would try turning your basal rate down an hour or two before you run. Switching into sport mode right before you start running won't affect your BGs during the run because the higher rate of insulin you've been getting for the past few hours is still acting in your body. I generally notice that any basal changes take at least an hour to make a difference in my blood sugar. I would even try just completely shutting off your pump for two hours, then having a gel and going for a run to be extra cautious. Then you can experiment with a shorter time or smaller % reduction once you stop seeing the drop.

Just got diagnosed as Type 1 last week at the age of 39. My C peptide was .2 but my antibodies came back negative. My Dr. Was stumped and ordered a CT scan for tomorrow but a Dr. friend said this is one of the four types of Type one and looking online the WHO says type 1b is something to be aware of. Anyone have any experience with this?

I’m sorry to hear that!
You don’t meet the typical diagnosis criteria for LADA or MODY, those are two of the more common “other types” of diabetes.
Overall the management is typically the same.

If you have any questions send me your email via DM.

I’m Type 1, a dietitian and former diabetes educator.

Do you mind if I ask U a query via pm? T1 myself

Wow the timing of this thread....I was just diagnosted as Type 2 two weeks ago. a1c results was 13.6%. I always thought I had a pretty decent diet, but could have a sweet tooth at times (apparently a lot). Moving forward, my eating is much more strict which has already began to pay dividends with my current BG levels. I havent had the time to read through all 14 pages of this thread, but am looking forward to so I can gain any knowledge I can. One huge concern of mine is, do I need to change my fueling stratgies at all or should I continue to use what works for me and just monitor my BG on my long training days?

Not at all. I sent you a PM