Respiratory rate and respiratory depth are seriously affected by respiratory muscle paralysis, severe intestinal disorders, ascites and obesity, as well as lung diseases, such as pneumonia, pleurisy, pleural effusion and pneumothorax. Rapid deep breathing as during strenuous exercising is due to the increased amount of oxygen needed by the body. Further, emotionally stress or nervousness increase breath rate and can cause hyperventilation, decreasing carbon dioxide levels in the blood and blood pressure, causing respiratory alkalosis. Patients often experience numbness in mouth and lower extremities, in severe cases, patients may present also with tetany and apnea. Severe metabolic acidosis is also associated with deep and labored breathing patterns, which increase the amount of carbon dioxide exhaled, thus lowering the serum carbon dioxide levels. PH levels also decrease. This results in some degree of compensation by discharging CO₂, so as to adjust the acid-base balance out of the cells as in diabetic ketoacidosis and uremic acidosis