Why do naps make me more tired?

Whenever i take a nap, i will sleep for like 3-4 hours, but whenever i wake up, i'm twice as tired as i was before! Does anyone know why this would happen? What can i do or take that would help me wake up non-cranky-like and rested?

People talk about sleep in hours but actually we should talk about sleep in cycles. I'm sure you're aware that as we sleep we go through various stages. Initially we doze lightly then we sleep more deeply and toss and turn a bit then we get very still and dream, then we repeat.

Each sleep stage is about 30 minutes and serves a different function. Deep sleep "resets" a number of motor functions and that's why we move so much. Dreaming sleep (better know as REM - rapid eye movement - sleep) is when the brain resets and sorts out short term memory to be filed for long-term storage (a very intense task which actually takes more brain power than being awake). Light sleep is the time between these 'body and mind maintenance' processes where the body clears the processes and gets ready to wake up.

If you wake up during deep sleep or REM sleep you will naturally feel tired and irritable. Your body and mind have been interrupted in the middle of something and they now need to deal with waking you up AND putting away these unfinished tasks.

The hitch is that everyone has different length sleep cycles. For some people they they can get it all done in 60 minutes. For others it's closer to 2 or even 2 and a half hours.

If you have an iPhone then there's an application for about $2 that will analyse your sleep patterns and wake you up at the best time.

If you don't have an iPhone then try experimenting with different length naps or make your naps less than 30 minutes long (experts recommend 15-20mins).

Best of luck.