Well, once we produce the lactate, these cells have special type of membrane transporters that stimulate these lactate molecules to actually move into the bloodstream. Why? Well, because generally speaking, skeleton muscle cells don't actually do anything useful with the lactate molecules and so they deposited into the bloodstream with the hopes that other cells, specialized cells, will pick them up and essentially recycle them and use them for something useful. And that's exactly what happens as we'll see in just a moment. So at the same time we're running, we also have these red blood cells which are also carrying out many different types of processes. And so in these cells, the red blood cells also uptake these glucose molecules from the bloodstream because they need to use the glucose to form the ATP.