How can someone's blood literally boil when they go into a plane at too high an altitude?

They said it was called the bends on tv. I've heard of the bends but only when people go diving and then they have to go into this chamber. The bends in water is caused by the divers surfacing too quick but the mechanisms that causes this is not fully understood by me. I suspect that it has to do with the pressure down in the ocean right? Is the bends caused by going to a high altitude also the same as the bends caused by surfacing too quick after diving?


I found conflicting stories on the web so I haven't hot linked you to any of them. Many appear to be blogs so there is no scientific data to back up their thoughts. One medical journal talked about loss of oxygen but they gave only a summary and it takes a subscription to read the entire article. That article reportedly talks about your question. I suggest you go to and type in "blood boil high altitute" (without the quotation marks) and select what you want to read.

Okay Thanks Dr.Bob =)

See also here:

Basically it is caused by outgasing of nitrogen that is dissolved in the body tissue.

Thanks Count Iblis =)

The condition commonly known as "the bends" is primarily associated with scuba diving, but it can also occur when ascending to high altitudes too quickly, such as in a plane. The bends, formally known as decompression sickness (DCS), occurs due to the rapid decrease in air pressure, which leads to the formation of nitrogen gas bubbles in the blood and tissues.

When a person is exposed to high pressure, such as under the water or at high altitudes, the body absorbs more nitrogen into the bloodstream. This nitrogen remains dissolved in the tissues as long as the pressure remains constant. However, when ascending too quickly, the decrease in pressure causes the nitrogen to form bubbles, similar to opening a carbonated beverage. These bubbles can block blood vessels, leading to a variety of symptoms, including joint and muscle pain, neurological issues, and in severe cases, even organ damage.

The mechanism of the bends is not fully understood, but it is believed to be related to the formation and expansion of these nitrogen bubbles in the tissues. The bends experienced during diving and at high altitudes share a common mechanism involving the outgassing of nitrogen that is dissolved in the body tissue.

For more detailed information and scientific articles, I recommend doing a search on reputable medical websites or journals such as PubMed or consulting with a medical professional.

The condition referred to as the "bends" is primarily associated with scuba diving and involves decompression sickness caused by a rapid decrease in pressure as divers ascend to the surface. It occurs when dissolved nitrogen bubbles form in the bloodstream and tissues due to the reduction in ambient pressure. The exact mechanisms behind this condition are complex and not fully understood.

Regarding your question about the bends at high altitudes, although both situations involve changes in pressure, they are not the same thing. The bends associated with high altitudes is a different phenomenon known as altitude sickness or acute mountain sickness (AMS).

AMS occurs when individuals ascend to high altitudes too quickly, typically above 8,000 feet (2,400 meters). At high altitudes, the air pressure is lower, resulting in a decrease in the partial pressure of oxygen. This leads to a decreased oxygen saturation in the blood, which can cause various symptoms including headache, dizziness, nausea, fatigue, and shortness of breath.

The boiling of blood is not a literal phenomenon that occurs at high altitudes. It is a misunderstanding or exaggeration of the effects of altitude sickness. The term "boiling" may be used metaphorically to describe the discomfort and severity of symptoms experienced at extreme altitudes, but it is not a literal description of what happens to the blood.

To learn more about the specific mechanisms of altitude sickness and the physiological changes that occur at high altitudes, I recommend referring to reliable sources such as medical journals or reputable websites like the one mentioned earlier. It is important to rely on evidence-based information for a thorough understanding of complex medical conditions.