I workout too about an hour after my last insulin shot. I usually take insulin 15 minutes before a meal but when i'm on a workout day i take it right before the meal, i have a slightly higher value when i start working out that way. I also tend to eat a bit more carbs (sometimes i add a slice of bread or something like that). After the workout i usually have to take 1.5 units of insulin with my post workout meal to remain stable. Though on occasions i do still spike a bit much later on. Since i only have 5 hours between finishing work and going to bed, i really need to cram a lot in that time to workout so sometimes my values aren't ideal. That said testing regularly both before and after makes for a better understanding of where my BG will go. The freestyle libre has helped me a lot more in that aspect but generally just testing and testing especially the first couple of weeks is a big help.