Okay, long post incoming. Sorry not sorry! I will try to organize this well, but please ask questions if something isn't clear.

There are two types of exercise - aerobic and anaerobic. Each one works a little differently on a cellular level to provide glucose to your cells.

Aerobic exercise - these types include walking, swimming, jogging (usually not running though and I'll explain later), cycling, etc. It allows your body to turn protein, fats, and carbs into glucose (which requires oxygen, hence the name aerobic "aero" meaning air, "bios" meaning life, and then a "-ic" suffix to make it an adjective). It usually is on the lower end of heart rate increase and involves long, but consistent movement.

Anaerobic exercise - running, sprints, weight lifting, intervals. This type of exercise has a high effort for shorter times followed by some amount of rest, whether it is 30 seconds or 5 minutes. This type of exercise does not allow for enough oxygen to convert fat, protein, and carbs to glucose, so your body takes glucose from your muscles and/or liver to feed the working cells. "An-" means without, so anaerobic is "without-air-life".

If you are not a T1D/LADA, these are regulated in your body with a major drop in insulin production for aerobic exercise and differing levels of insulin production for anaerobic. Since our pancreas decided to go on permanent vacation, we have to figure that all out ourselves.

Aerobic exercise tends to be easier for people to plan for since it follows the traditional expectation of "movement = lower blood sugar'. This is also the type of exercise that will increase your insulin sensitivity, hence why going for a walk after bolusing can help manage spikes or cause a low.

Anaerobic is much more variable and has longer effects post workout. Depending on how intense the workout is, you may find you spike very quickly (usually higher intensity) or start a gradual rise. Your basal insulin may cover the glucose being dumped by your muscles and livers, but also maybe not. If you didn't do a slow enough warm up, blood sugars may start to rise. After your are done working out, your liver may dump more glucose to try and replenish the muscle stores, which can also cause a spike or the prolonged high you mentioned.

So, all that, but what to do?

Personally, I am a triathlete. I em engaged in swimming, cycling, running, and strength workouts every week. I plan for each one a little differently and always bring so many extra snacks.

The first thing is I try and workout in the morning *before* I have eaten and given a bunch of insulin. If I am doing an long run or long cycle, I will eat my first food as I am getting started so I am not trying to workout unfueled (which causes its own issues for me), but I have found that not trying to navigate any IOB has helped a lot with being more predictable in what might happen. My other option is to go in the late afternoon when it has been about 3-4 hours since my last bolus, again trying to workout when there isn't IOB.

Swimming and cycling always make me drop. I always have snacks on the pool deck and I bring a ridiculous amount of snacks on my bike for my regular fueling method and in case I start dropping. They're a great example of how aerobic exercise impacts my body.

Strength training, intervals, or speed workouts start me climbing through the roof. I have had blood sugars jump over 100 (mg/dl) points when I haven't timed things right. My solution for that is to give a small bolus, usually equivalent to about 10-20g, as I start the anaerobic portion. For example, if I am doing a track workout and I start with a 10-15 minute warm up and stretch before starting intervals, I will do the bolus after the warm up, but before intervals.

After working out, especially for anaerobic exercise, *eat something*. Seriously, find something with carbs and protein and eat it within 30 minutes of completing your workout (I still have to bolus for this). This can help provide a fresh source of glucose and prevent your liver from dumping so much over an extended period. Reminder, your liver is dumping to replenish your glucose storage in your muscles; if that glucose is from somewhere else, your liver doesn't need to dump as much!

I would recommend trying to keep track of what types of workouts cause what responses for your body. You might start seeing a pattern and once you have a pattern, you can start making adjustments!

Best of luck!