I few comments and thoughts to share with you.
I am very glad you got some experience with injections before going to the pump. It really helps you get a better understanding of how everything works!
There is definitely an impact with adrenaline and cortisol with sports. It is not only the physical activity, but the mental component as well. On top of that, when a pump does a higher BG target or you do a manual cut to basal, that makes the spike even worse.
One way to help mitigate that is to do BG checks whenever he is able. Like if he is coming off the field for a substitution and he will have a few minutes to do a BG check and can take insulin to counter the spike. Or at halftime he can do that. When he has a few minutes of not being on the field, a BG check is super useful.
Let me counter this suggestion with a different idea.
Do you know much about muscle glycogen?
Yes, cutting basal can help mitigate a drop after a game. But do you know what cutting basal can’t do? It can’t help him replenish his muscle glycogen after a game. The only thing that can help him (or anyone) efficiently replenish his muscle glycogen after an activity is carbs and insulin.
I have preached this a million times on FUD. You are thinking that’s nuts. Taking insulin after an activity. Sure, it’s nuts if you don’t also take sufficient carbs with it.
Ask @daisymae. She has been doing this for a while now.
Muscle glycogen is stored carbs your muscles use for fuel during an activity. After an activity, your muscle glycogen is depleted (how much depletion depends on the intensity and duration of the activity).
Replenishing it rapidly after an activity is not necessary for things like walking, hiking, or sports that are less endurance-based, like baseball.
But for something like soccer, what will help him quite a bit is to make sure he restores the muscle glycogen quickly. That will help reduce the lows that will follow in the 24 hours after an activity (as his body is trying to recover), and will also help him perform better if he has another game or practice soon after.
A reduced basal is fine for the hours that follow a game. That will help reduce the lows. But I suggest he also bolus and take carbs immediately after an activity.
His bolus amount won’t follow his normal ratio. After an activity, he can take much less insulin per gram of carbs than normal. So it take a bit of practice to get the amount dialed in correctly.
A few other suggestions for helping to manage BG. I am a big fan of BG checks whenever possible. The CGM delay can make it less useful for sports. But during a game, a BG check may not be possible. A great tool that can be used is the Bluejay watch. (Very affordable, about $100 and everything you need is included.)
While an apple watch requires the phone to be nearby, the Bluejay watch does not. It reads directly from the Dexcom sensor.
(Since he is using the O5, you would need to set the watch to use the phone slot, and make sure you turn off the phone while he is using the watch. We can discuss the details about this if you want to try that watch).
Some specifics to soccer (I played for my college JV team, and I’m also a state certified coach where I live). In soccer, a lot of refs will tell the kids they need to remove their watch. I would just cover it with a sweatband. That way it’s totally unnoticeable. He can pull the sweatband away to look at the number when he wants to check his BG. It’s a very inconspicuous way of doing it.
(You could probably also go the route of saying it’s a medical device and should be allowed in the game, but that’s just more hassle and calls more attention to him. I would just cover it with a sweatband. It’s super easy and stealthy.)
Finally, for soccer another important thing is for him to have carbs with him on the field. Most of the higher level soccer leagues do not permit shorts to have pockets. It’s a safety concern, because fingers can get caught in a pocket when jostling for a ball.
My mom sewed a small pocket INSIDE my soccer shorts. So the refs would never say they were illegal. I carried little sugar packs inside the pocket.
The best place to put the pocket is on the front, but not on the hip. If he falls in a game, most likely anything in there would hurt to land on it.
The best place is on the front of the shorts, midway between where his bellybutton and hip are. It’s easy to get to, but it’s generally a place you do not land when you fall. (The back is a little harder to get to.)
Anyway, a bunch of stuff here. Hope this stuff helps.
BTW, is he eating sufficient carbs in his diet? For sports, I am a big believer in the value of carbs as fuel.