You always have Lactic acid in your blood
Did you know that you always produce lactic acid, even when you are not exercising?
Even when you are resting you produce about 1.5 mmol, and until 2011 it was not known why 4mmol was a relatively fixed point where the muscles could not manage to work anymore because of the this.
In 2011 there were made a scientific study that showed that your kidneys make sure to transport the lactic acid away up to and including moderate exercise levels.
For heavier exercise levels your liver make sure to do the remaining work. So if your liver is not working properly it can not help in the same way as if operating optimally.
So - eg. don't drink alcohol combined with serious training because alcohol do harm the effectiveness of your liver.