Hi,
Have a look at this :
http://forums.braintalk2.org/showthread.php?t=1462
"Everyone talks about it"
You raise a problem that I experience though I don't have PD (I have chronic fatigue) : when I exercise in the morning, I can feel exhausted all day, have to sleep to recover. But it is not systematic. The non-systematic and unpredictible pattern of my fatigue makes it hard for me to hold a schedule like "I will have exercise from X o'clock to Z o'clock". The advice I got was to have a quarter fom time to time rather than half an hour and yes, it doesn't wear me off. But I forget...
Ok, it's not like I don't get any exercise at all : I live in the woods and often go for walks, I have the housework and often do it while dancing, singing and playing music to boost me.
Greetings
Karine