Symptoms of CNH have been observed to vary according to the progression of CNH. The initial symptoms of CNH include a low arterial partial pressure of carbon dioxide, a high or normal arterial partial pressure of oxygen, high arterial pH, and tachypnea. The partial pressure of carbon dioxide has been noted by Yushi et al. to drop as low as 6.7 mmHg, while oxygen saturation remains at 99-100%. Respiratory alkalosis is induced in people affected with CNH, which stimulates the hyperpnea to attempt to compensate the rise of the blood’s pH. Some of the reported cases of CNH claim alkaline cerebral spinal fluid (CSF). However, not all of the cases experience this effect and other cases of CNH have a local increase in the pH surrounding the tumor that causes the condition. The hyperventilation of CNH patients persists during sleep. Those affected have been observed to not be able to voluntarily control their breathing in order to slow it down and the hyperventilation is predominantly controlled by the diaphragm.