So the average partial pressure of oxygen in our tissues is around 40 mercury. Now, at lower PH values, when the cells of our tissue are exercising, we shift the curve to the right and this means we make the hemoglobin much more likely to actually dissociate and unload that oxygen into the exercising tissue. So this in turn will deliver more oxygen to those tissues because those cells of the exercise tissue will need more oxygen to produce more ATP in the process of cellular respiration. So even from this curve we see that at a PH of 7.4, on the blue curve we see that at a 40 mmhd partial pressure we have a 70% saturation of hemoglobin. But at the same exact partial pressure inside our exercising muscles, inside our exercising tissue, at a PH of 7.2 we have a lower percent saturation, means more of the hemoglobin have unloaded that oxygen. So about 40% of the hemoglobin actually exists in its dissociated form because all that oxygen has been unloaded.