My almost 6 month old DS used to have couple of naps a day of anything between 45 min and hour and half. Recently though he seems to be managing a max of 30min (this morning was only 25) before waking up crying (he never wakes up crying after sleeping at night BTW)(he has also then been rolling onto tummy whilst crying lately and can't roll back at the mo). I go up (turn him back onto back) and he still seems tired to me. He tries to turn over, puts his thumb in as if to go to sleep, then after a few seconds continues the roll and ends up flayling on tummy again. We go through this routine several times in 5 mins or so by which time he either seems in a bit of a state/seems quite awake. I can't help thinking he needs longer though as once he gets downstairs he has thumb in again and looks done for! Any suggestions?? Since he had bad cold a couple of weeks ago we have also been having same thing on going to bed for the night. He used to just lie in cot awake, turn to side and put thumb in and after maybe a little bit of calling out etc, would go to sleep but has been real crying and screaming to go to sleep this last week or so. Last night it took almost 2 hours to get him to sleep. Even picking him up didn't console him at times!!
This gross motor development can wreak havoc on their sleep. They come out of a sleep cycle (30-45 min) and instead of going back into a deep sleep, they're trying to roll/creep/crawl/etc. He also has his 6 month growth spurt coming so he could be getting hungry, too.