There is no change in her activity level as far as I can tell. She has a very clear cycle: When I feed her she retreats to her hiding box and stays warm over her heating pad (under the cage, not touching her) for about a week. Then she comes out and is very active, looking for her next meal, for the next two or three weeks. If I feed her at week four or so the cycle starts over. If I don't feed her she comes out less frequently and then stays in her box more and more until I do feed her.
When I take her out to hold her it is usually during the evening while I am watching TV. She rests during the day with her head positioned so she can see out the door of her box. If I feed her at week four she will notice the change in routine as soon as I arrive during the daytime (coming home from the pet shop) and take the top off of her cage. She comes out of her hiding box like a moray eel and grabs the first mouse right out of my hand (I dangle it by its tail). Then I let the second mouse loose on the top of her hiding box and she hunts it down after the tail of the first mouse goes down her throat like a last slurp of spaghetti.
If I don't feed her until week six or seven she will be in a torpor and she won't come out of her box until she hears the mice running back and forth on top of her hiding box. When she appears I pick up one mouse by the tail and dangle it for her to grab, then she eats it and hunts down the second one.
I have a heating pad under her cage and a temperature sensor under the towel that covers the bottom of her cage, right over the heating pad. If she is out and about in her cage the temp sensor reads 84 or 86 F. If she is sleeping or digesting right on top of the sensor, over the heating pad, the sensor will read 96 or 100 F.