It's somewhat painful to do - to deliberately expose poorly - but I will sometimes purposefully underexpose one stop to avoid going up a stop in ISO.
Sure, it's bad photography practice to under-expose (from a get-it-right-in-camera) standpoint, but shooting that way leverages the Sony sensor's unique strength: shadow and exposure recovery. It's unthinkable with a 5D III, which has horrible noise in shadows/underexposed areas, but works great with the a7. It may not be a good solution for you, but give it a try and see if it's a work-around towards minimizing ISO noise.
Typically thats what I do and i've done that with my 5D3. I'll give it another shot and focus on lower ISO and mess with the shadows and highlights a bit more.