Acidification of the body is considered to be the source of all diseases, and some domestic scholars have mentioned that the increase of acidic components in the blood will form an acidic body. If the body is acidic for a long time, the endocrine system, the nervous system and the function of internal organs will be affected to varying degrees, the body will suffer from calcium deficiency, blood color deepens, viscosity increases, people often feel fatigue, memory loss, lack of concentration, loss of appetite, dull skin, insomnia, dreamy, diarrhea, constipation, etc., and may lead to diabetes, neurological and cardiovascular Many diseases of the nervous system and cardiovascular system. Most of the symptoms mentioned above are very common in patients with anxiety and depression. However, for a long time, there has been a lack of easy and accurate methods to detect acidity. Several tests mentioned in foreign studies: NEAP represents the daily net acid production of the metabolic system, which is closely related to the daily net acid excretion (NAE) of the kidneys, and another indicator commonly used to estimate NEAP is the 24-hour urine pH. These metrics are relatively cumbersome to manipulate and the results are highly volatile. Some of them only take into account the food factor and not the human factor, since each individual has a different ability to metabolize acid. Arterial blood mainly reflects alveolar gas exchange, and it is difficult to affect alveolar gas exchange and the results of arterial blood gas analysis when it is not a serious physical disease. In particular, the pH of arterial blood is precisely regulated, and despite the pressure on the body’s buffering capacity, acidosis cannot be detected without reaching the level of acidemia. The results of venous blood gas analysis are different. This is because venous blood primarily reflects tissue gas exchange. The mixed venous blood gas analysis is taken before pulmonary gas exchange, so it can reflect the tissue respiratory metabolism more accurately. PO2 at the arterial end of capillaries is equivalent to PaO2. When blood flows through capillaries, the surrounding tissues continuously take up O2 from arterial blood, resulting in a continuous decrease in the partial pressure of oxygen in capillaries, which is equal to PvO2 when it reaches the venous end. Therefore, PvO2 is considered to be a valid indicator of tissue oxygenation. That is, venous blood gas analysis can also be used to evaluate tissue acid-base status and tissue oxygenation status. In my previous study, I found that depressed patients had elevated venous blood pH, decreased PvCO2, and elevated PvO2/SvO2/CvO2, and the cognitive impairment factor was positively correlated with PvO2 with a very significant statistical significance; suggesting that the results of venous blood gas analysis in depression suggest the presence of acidic metabolite accumulation and tissue hypoxia. The study also found that PvO2 is an extremely sensitive indicator. if PvO2 is below 22mmHg, such people have good appetite, sleep well and have energy during the day; if PvO2 is between 23-29mmHg, such people sleep well but cannot wake up and have more obvious drowsiness symptoms; if PvO2 is above 30mmHg, such people must have insomnia symptoms and most of them also have anxiety; if PvO2 is above 30mmHg, such people must have insomnia symptoms. Most of them also have anxiety; when PvO2 is above 40mmHg, such people have suicidal thoughts. Of course, in addition to PvO2, there are also corresponding changes in venous pH and PvCO2, but the fluctuation of PvO2 is the most significant. This fluctuation of PvO2, venous pH and PvCO2 reflects the body’s change from normal – drowsiness – insomnia – anxiety – depression. -depression, the process of acidity from nothing to something, from mild to severe. Therefore, they should be more specific indicators of acidity/acidosis. Therefore, insomnia, anxiety and depression are not simply psychological disorders, it has appeared as an alteration of physiological test indicators, which are clearly related to acidosis.