power problems?

I have my Mac, and most of the times I use it on my bed and I feel it heats a lot and the fan starts like spinning a little faster, would you think this might cause a bigger problem ?, or I'm better off using it on the desk?

Thanks

I was reading the manuel and Apple recommends to use the Macbook on a flat level surface. Apple also says to avoid putting the Macbook on a pillow because it can get hot. Try using your Mac on a desk and see if the fan spins like when you use it on your bed. Hope that helps.