You have to apply the ratios that you use normally. That's the only way it will work.
as above said you need good carb counting ratio to your insulin intake. my diabetic nurse said to me to work out your ratio do the following.
If your far too high in high hypoglycaemia do not train. rest and learn with your gp or nurse
remember most insulin unit measures one unit on pen to 3 mmog levels of sugar..
●dont train on high level sugars do light workouts like walking
●rest and rehydrate with water