This likely has to do with inverted cortisol circadian rhythm. See, cortisol increases adrenaline levels. Specifically by increasing the action of the PNMT enzyme that converts noradrenaline into adrenaline. When cortisol spikes, adrenaline follows. Normally cortisol is higher at the beginning of the day (to get you jump started), is lower during the day with some peaks here and there depending on your stress level and then comes down in the evening to allow you to unwind.
There is also a connection with melatonin production. Melatonin brings cortisol down (which will also bring adrenalin down). People with a low melatonin production can also stay more neurologically active in the evening.
So if you have low melatonin and/or a reverse cortisol cycle you will have a hard time getting started in the morning and get more and more activated as the day goes by. Nornally this is a bad sign because it is a symptom of overstress. BUT I believe that some people are actually born like that.