The Magical Hyperbaric Oxygen Therapy

Hyperbaric oxygen therapy (HBO) is a non-invasive, purely physical treatment that can be used both for symptomatic relief and as a rehabilitation method. It has hundreds of indications. In recent years, it has also become a “magic remedy” for some young people seeking stress relief and relaxation.

Oxygen therapy includes normobaric oxygen therapy and hyperbaric oxygen therapy. At normal atmospheric pressure and under high pressure, oxygen inhalation differs fundamentally in three aspects:

1. Different requirements for pressure equipment: Under normal atmospheric pressure, patients receive oxygen via methods such as nasal cannulas, face masks, oxygen tents, or mechanical ventilators—all under conditions of one atmosphere. In contrast, when receiving oxygen at high pressure, patients inhale pure oxygen in a specially designed hyperbaric chamber, where the ambient pressure exceeds one atmosphere.

2. Different oxygen concentrations during inhalation: Under normal atmospheric pressure, the oxygen concentration during inhalation typically ranges from 25% to 55%, whereas under hyperbaric oxygen therapy, the oxygen concentration is between 85% and 99%.

3. The therapeutic effects are dramatically different: Under high pressure, oxygen inhalation can increase blood oxygen levels by several to dozens of times compared to oxygen inhalation at normal atmospheric pressure.

Under hyperbaric oxygen therapy, the amount of physically dissolved oxygen in the blood can also increase significantly. Experiments have shown that for every additional atmosphere of pressure in a hyperbaric chamber, the amount of physically dissolved oxygen increases by 14 to 17 times compared to breathing under normal atmospheric pressure. A renowned paper titled “Life Without Blood,” published by Dutch scholar Boerema, confirmed that animals with virtually no blood cells can still survive under hyperbaric oxygen conditions. However, under normal atmospheric pressure—even when breathing pure oxygen—animals devoid of red blood cells will quickly succumb to hypoxia and die. Under hyperbaric oxygen therapy, the body’s oxygen reserves also increase: at three atmospheres of pressure, an animal can remain without brain death for 17 to 26 minutes after cardiac arrest; whereas under normal atmospheric pressure, breathing air alone, an animal will experience brain death within just 4 to 6 minutes after cardiac arrest. Other direct effects of hyperbaric oxygen therapy include: enhancing the diffusion of oxygen in the blood and increasing the effective diffusion distance of oxygen within tissues; exerting an inhibitory effect on bacteria; compressing and dissolving gas bubbles; and modulating systemic bodily functions—all of which cannot be achieved with normobaric oxygen.

Hyperbaric oxygen therapy for the treatment of diseases primarily relies on the following effects:

1. Effect of Pressure: When pressure increases, the volume of gas bubbles in the body decreases, facilitating their dissolution into the bloodstream and subsequent elimination from the body through respiration. Therefore, air embolism and decompression sickness are unique indications for hyperbaric oxygen therapy.

2. Increasing Oxygen Content in the Blood: Oxygen is transported in the blood through two primary mechanisms: one is oxygen bound to hemoglobin, and the other is physically dissolved oxygen in the plasma. Under normal atmospheric pressure, every 100 ml of blood can carry approximately 19 ml of oxygen bound to hemoglobin, whereas the amount of physically dissolved oxygen in the plasma is only about 0.3 ml. During hyperbaric oxygen therapy, the amount of physically dissolved oxygen in the plasma steadily increases as the partial pressure of oxygen rises. For example, when breathing pure oxygen at 3 ATA (3 atmospheres), the amount of physically dissolved oxygen in every 100 ml of arterial blood can increase to as much as 6.4 ml. Thus, under hyperbaric conditions, the physically dissolved oxygen content is more than 20 times greater than that achieved when breathing air at normal atmospheric pressure. When breathing pure oxygen at 3 ATA, the body’s metabolic needs can be met solely by the dissolved oxygen in the plasma. In critical situations—such as significant loss of hemoglobin or conditions where hemoglobin has extremely poor oxygen-binding capacity or even completely fails to release oxygen—physically dissolved oxygen plays a decisive role.

3. Increasing the oxygen content and oxygen storage capacity of tissues: During hyperbaric oxygen therapy, blood oxygen tension and blood oxygen content increase several times compared to normal atmospheric pressure, facilitating the easy diffusion of oxygen from capillaries into tissues, thereby increasing the oxygen content within the tissues. Moreover, the dissolved oxygen in plasma diffuses into tissues without requiring energy expenditure, allowing for rapid correction of tissue hypoxia.

4. Increasing the Diffusion Distance of Blood Oxygen: Gases diffuse from areas of high partial pressure to areas of low partial pressure in order to achieve equilibrium. The rate and distance of diffusion depend on the magnitude of the partial-pressure difference—greater partial-pressure differences result in faster diffusion rates and longer diffusion distances. In conditions such as inflammation, trauma, and burns, tissue cells become edematous, and the distance between cells and capillaries increases. Under normal atmospheric pressure, oxygen inhalation alone may not be sufficient to meet the oxygen demands of these edematous tissues. However, hyperbaric oxygen therapy can achieve an effective diffusion distance for blood oxygen, thereby ensuring adequate oxygen supply to these tissues.

5. Vasoconstrictive effect: Hyperbaric oxygen has a vasoconstrictive effect, which can reduce local blood volume and minimize exudation. Consequently, it helps alleviate edema following cerebral edema, burns, or crush injuries. Although the vasoconstrictive effect of hyperbaric oxygen reduces local blood supply and makes it more difficult for red blood cells to pass through capillaries, the amount of oxygen delivered to tissues via plasma with its elevated oxygen tension is significantly increased.

6. Antibacterial effect: Oxygen exhibits a broad-spectrum antibacterial action, effective not only against anaerobic bacteria but also against aerobic bacteria.

7. Elimination Effect: During hyperbaric oxygen therapy, the high partial pressure of oxygen in the body can accelerate the elimination of other harmful gases. For example, a high partial pressure of oxygen can speed up the dissociation of carboxyhemoglobin, thereby promoting the removal of carbon monoxide and restoring hemoglobin’s oxygen-carrying capacity. The higher the arterial oxygen partial pressure, the more pronounced the dissociation of carboxyhemoglobin and the elimination of carbon monoxide become. For instance, the half-life of carbon monoxide under normal atmospheric pressure is 5 hours and 20 minutes; under normal atmospheric pressure, breathing pure oxygen takes 2 hours and 20 minutes; whereas during hyperbaric oxygen therapy, it takes only slightly more than 20 minutes.

8. Health Benefits: As we age, cells in the body—such as brain cells—may experience hypoxia, ischemia, and insufficient aerobic metabolism. Regular and adequate oxygen supply can slow down and reduce both the rate and extent of cell death. In addition, hyperbaric oxygen therapy offers various health benefits, including promoting blood circulation to remove stasis and improve blood flow, enhancing the body’s immune function, improving sleep and gastrointestinal function, boosting memory, neutralizing oxygen free radicals, and beautifying and nourishing the skin.