It sounds like you have a pretty old laptop? Cogmind is not too demanding (when I play it uses literally 3% of my CPU, which is about 3 years old), but it is run entirely on your CPU (no GPU processing). The game idles as long as it's hitting 60 FPS, because the game is capped at that speed by default. If it's eating up cycles then you must be getting under 60 FPS on your machine.
Aside from the obvious running in windowed mode and/or making the view smaller by using a smaller font and/or map, one way to reduce the load is to cap the FPS at something below 60 to give your CPU a breather.
This option is available directly in /user/cogmind.cfg towards the bottom:
fpsCap=60
Try some different values like 50, 40, or 30 if you it doesn't bother you,
Although Cogmind is turn-based, it still has to render the UI and anything that might be animated, and it does that at 60 FPS.
Let me know if that helps!
(I'm moving this thread to the Support board.)