Well a collision is a collision regardless of the speed (as far as construct is concerned). So you need to do something like,
if sprite1 speed >= 5 AND on collision then subtract 5 from sprite1's hitpoints
else if sprite1 speed >= 10 AND on collision then subtract 20 from sprite1's hitpoints, and so no and so forth. Something like that anyways. (I know construct doesn't write it like that, but its easier to follow the logic).
If you're using physics though it might be more complex.