Short keys == faster lookups?

[Per Ejeklint]

Please excuse a silly question from a newbie. I have a db that grows  
pretty fast (data measurements done every minute all year around). I  
wonder what I save if I mangle keys to be as short as possible. Like  
instead of calling things "temp_outside" I rename them to "t_o" or  
something like it. The size of the db will of course shrink, but will  
it do anything for indexing/lookup speed when I search in the db?

/Per