An increase in carbon dioxide (CO2) will lower the pH so in order to decrease the CO2 you need to increase the minute ventilation (= tidal volume x breathing rate) by increasing either or both. That is for acute respiratory acidosis, treatment for metabolic acidosis is much more complicated however normalizing the blood pH (back closer to 7.4) with changes in the minute ventilation allows time to implement treatment. This is a subject that has to do with Arterial Blood Gases (ABG's) a test that determines the acid - base status of a patient. Patients with ABG's that are out of normal may need help (mechanical ventilation) to correct the pH balance.
How do patients react when this value becomes lower? is it really a bad and dangerous health concern?
That requires a visit to the doctor .. if you have acidemia, you need to have it treated.