I've always wondered about this because when dd's ill she always does these incredibly long daytime naps. She's 2 and currently has a horrible fluey cold thing with a fever and she slept almost 3.5 hours this afternoon. After 2.5 I made an effort to wake her up but she just couldn't open her eyes so I left her and eventually got her up an hour later and she still seemed like she could've slept more. The thing is she always sleeps dreadfully at night when ill and although part of that is because she's ill and uncomfortable I also wonder if I should regulate the day sleep despite that she's ill.