My fasting sugar level

sometimes adrenaline while exercising spikes up ones blood glucose.. as it is kind of a stress to exercise..
but don´t focus on that spike , later in the day ones numbers will usually be lower when one have been exercising conpared to when not having exercised..

also very much protein eaten in excess to what the body need can contribute along with carbs in raising blood glucose...

if you didn´t eat before exercising it can also be the dawn phenomenon which is the liver producing more blood glucose in the morning , this is a natural phenomenon though can be more markedly in type 2 diabetics where their liver is a bit or a lot more active in transforming proteins into blood glucose...

usually the dawn phenomenon stops raising when people have their first meal of the day