Courses for Kids
Free study material
Offline Centres
Store Icon

pH of Blood: Balancing the Body's Vital Levels

Last updated date: 22nd Jul 2024
Total views: 370.2k
Views today: 10.70k
hightlight icon
highlight icon
highlight icon
share icon
copy icon

Introduction to Blood pH

For aspirants preparing for the National Eligibility cum Entrance Test (NEET), grasping the intricate details of human physiology is imperative. Among the fundamental concepts is the pH value of blood, which plays a pivotal role in maintaining homeostasis within the body. In this article, we delve into the significance, regulation, and clinical implications of blood pH, essential for excelling in NEET examinations.

pH, or "potential of Hydrogen," is a measure of the acidity or alkalinity of a solution, ranging from 0 to 14. A pH of 7 is considered neutral, while values below 7 are acidic and above 7 are alkaline. In the context of human physiology, maintaining an optimal pH level is vital for various biochemical processes and overall health.

What is the pH Value of Blood?

In humans, the normal pH range of arterial blood typically falls between 7.35 and 7.45. When it goes above or below this range, it can cause serious problems and could even be life-threatening if not controlled.

The pH value of blood indicates the acidic or alkaline level in the body. The normal pH of blood is essential for the proper functioning of the optimal activity of the body. Hence, because of this the body physiologically balances the blood pH range. The pH of human blood normally range from 7.35 to 7.45 for a healthy person.

How Blood pH is Maintained?

The pH of human blood is very well regulated by maintaining an acid-base balance. It is very essential to maintain this homeostasis. Various factors play their part in regulating the pH level of blood. The blood plasma pH depends on the concentrations of CO2, electrolytes and weak acids. There are two main organs, the lungs and the kidney, that are involved in the balancing of the acid-base concentrations. The mechanism by which they do so is:

  • Respiratory Regulation - Lungs: They have the most significant role in exchanging gases with the blood. They remove CO2 by the gaseous exchange. The brain regulates the breathing activity and so the brain along with the lungs maintain pH value of blood by regulating the speed and intensity of the breathing.

  • Renal Regulation - Kidney: Kidney is involved in the ultrafiltration of the blood and takes away the waste material from the blood and finally excretes them. Thus, in the process, any acid or base present in excess in the blood is removed thus maintaining pH of blood in human body.

Thus, the human body balances what is the pH of blood via respiration, excretion and other metabolic activities.

Buffer Systems Maintaining pH Level of Blood:

Inside your body, there are different systems that keep your blood's pH stable. They prevent big swings that could cause problems. The main ones are the bicarbonate, protein, and phosphate buffer systems. Together, they absorb extra hydrogen ions (H⁺) or hydroxide ions (OH⁻) when necessary to maintain the right balance.

Role of Carbonic Acid-Bicarbonate Buffer System:

The carbonic acid-bicarbonate buffer system is super important for keeping the pH level of blood just right. It works by a back-and-forth reaction between carbonic acid (H₂CO₃) and bicarbonate ions (HCO₃⁻). Depending on what our body needs, it can either release or soak up hydrogen ions.

Why is Blood pH Important?

Any changes that occur in the blood, due to an increase in acidic level (acidosis) or the basic level (alkalosis) is a cause of worry. This can happen due to impaired function of the lungs or the kidneys organs since they are the ones responsible for cleaning the blood of unwanted products. Changes in the normal pH of blood are generally associated with kidney failures.

Sometimes what is the pH level of blood is affected due to dysfunction of some other organs as well because of which there can be a release of the acidic and basic materials in the bloodstream. Thus, the normal pH of blood is important because it states the healthy state of internal organs of the body, specifically the kidney and the lungs.

Due to changes in the concentration of waste materials such as carbon dioxide, electrolyte and other acidic substances, the concentration of the oxygen dissolved in the blood changes and this, in turn, affects the respiration process of the cell. Once cellular respiration is damaged, the cells begin to die and can result in catastrophic events in the body such as organ failure and subsequent death. Thus, maintaining what is the normal pH of blood becomes extremely important for survival.

Causes of Abnormal pH Value of Blood

Organ dysfunction especially of the kidneys and lungs result in too high or too low levels of blood pH range. An increase in the acidic or the basic content is also indicative of grave diseases of the heart, lung or kidney and also indicate poisoning, infection, and diabetes.

High pH Value of Blood

High blood pH range is known as alkalosis (above 7.45). Under this condition, the blood becomes more and more basic as the pH goes higher than the normal pH of blood. The following are the reasons for the changes in the blood pH range taking the value higher than what is the normal pH of blood:

  • Excess loss of fluid because of the increase in urination, vomiting, diarrhoea, etc is one of the primary reasons for the value to get a higher pH value of the blood. If noticed, these symptoms are some symptoms of diseases such as cholera, dengue, etc. Thus a temporary illness, in this case, is the reason for the high pH value of the blood from what is the pH of the blood.

  • When kidneys are unable to remove the excess of the alkaline materials due to improper functioning, it can lead to a rise in the pH value of blood.

Low pH Value of Blood

Low blood pH range is called acidosis (below 7.35). In this condition, the blood becomes more and more acidic as the pH goes lower than the normal pH of blood. Also, this is more common than alkalosis. The main reasons the normal pH of blood goes lower are given below:

  • In diabetic patients, when the body is unable to produce enough insulin, it can lead to another problem of the release of acidic ketones in the blood. This is called ketoacidosis andis another complication of diabetes. Symptoms include fatigue, confusion, and rapid breathing.

  • The renal failure of the kidneys because of any disease or deteriorating health leads to metabolic acidosis. 

  • Respiratory diseases such as pneumonia, bronchitis, asthma, chronic pulmonary disease in the lungs can lead to acidosis.

So, the answer to the question - why is pH level of blood important? - can be given as Blood pH range is vital for cellular respiration and intake of oxygen by the cells from the blood and also many times to diagnose diseases because these changes occur owing to organ failure because of a variety of reasons, the pH value of blood is an important determinant of the disease condition of the body. 


Understanding the pH value of blood is essential for NEET aspirants, as it is a fundamental aspect of human physiology and critical for maintaining overall health. Mastery of this topic involves comprehending the intricacies of blood buffer systems, regulatory mechanisms, and clinical implications of pH imbalances. By grasping these concepts, aspirants can confidently tackle questions related to pH of blood in the NEET examination and develop a deeper understanding of human physiology as a whole.

FAQs on pH of Blood: Balancing the Body's Vital Levels

1. What is the pH of Blood?

The pH value of blood lies between 7.35 to 7.45. Any change, even a minor one in this blood pH range can have severe implications. This pH value of the blood is the representation of a healthy human being. 

2. What Happens When the pH of Blood is Too High?

When there is high basic content in the blood, the pH value increases more than the normal value. This condition is called alkalosis. This is indicative of the disease conditions such as an increase in urination, vomiting, diarrhoea, etc. Also, when the kidney is unable to clear the basic content from the blood, it results in high blood pH.

3. Does the pH of blood change?

Yes, but within a very small range.  Normally, blood pH is tightly controlled by your body's buffering systems.

4. How does blood maintain pH?

Kidneys and lungs work together. Kidneys remove excess acid through urine, while lungs expel carbon dioxide, a weak acid.

5. What can increase pH of blood?

Blood pH can rise due to excessive vomiting, diarrhea, or sweating, which throws off your body's electrolyte balance.  Another cause is hyperventilation, or rapid breathing, which expels too much carbon dioxide, a blood acid.

6. Why is pH in blood important?

pH in blood is crucial for many bodily functions. Enzymes, essential proteins for most cellular processes, only function effectively within a specific pH range.

7. What is the full form of pH in blood?

pH doesn't have a full form. It stands for "potential of Hydrogen" and refers to the concentration of hydrogen ions in a solution, which determines its acidity or alkalinity.

8. Is blood pH neutral?

No, healthy blood pH is slightly acidic, typically between 7.35 and 7.45.

9. How to measure blood pH?

Blood pH is measured through a blood gas test (Arterial blood gas (ABG)), which analyzes the pH, oxygen, and carbon dioxide levels in arterial blood.

10. What causes low pH of blood?

Several conditions can cause low pH of blood, including:

  • Kidney disease: When kidneys can't properly remove acids.

  • Uncontrolled diabetes: Ketone buildup due to lack of insulin.

  • Lactic acidosis: Buildup of lactic acid from strenuous exercise or certain medications.

  • Diarrhea or vomiting: Loss of bicarbonate, which helps regulate blood pH.

  • Certain medications: Like aspirin overdose or methanol poisoning.