At least 91 people have been killed when a massive tornado tore through Oklahoma City on Monday. Wind speeds measured up to 320km/h and entire neighbourhoods, schools and a medical centre have been destroyed. Rescuers are still searching for survivors. How long can the average person survive under rubble?
For a young, healthy person who started the ordeal well-hydrated and
well-nourished, the chances of surviving are fair if they are rescued
within about four days. The time period goes down considerably under
Someone who is injured, particularly if they have lost blood, has a
very poor chance of surviving for more than 24 hours. In fact, even if
someone is not injured, experts agree that the person's chances of
survival drop once 48 hours have passed.
No food or water
What happens to the body without food and water over an extended period?
The lack of food is of less importance than the lack of water. The body
can call on fat stores and eventually the protein in muscle for fuel,
but it cannot draw water from anything other than external sources.
Kidneys are the organs most severely affected by lack of water. Their
chief function is to maintain both the volume and the concentration of
Without water, the body gradually dehydrates because water intake no longer replaces water lost through sweating, breathing, passing urine and absorption in the gut.
With increasing dehydration, the blood becomes thicker, which causes
the kidneys to retain water and concentrate the urine they do produce.
This causes the blood pressure to fall, resulting in less blood passing
through the kidneys. Thus yet more water is retained and urine becomes
even more concentrated. Eventually, no urine is produced at all.
Once this happens the person is in danger of kidney failure.
As dehydration increases, so does thirst, and tiredness. Eventually,
when the kidneys have stopped producing urine, the person may become
confused and even lapse into a coma as the kidneys start to fail.
Drop in blood pressure
Obviously, in a traumatic situation such as if someone is trapped under rubble, many
other factors might complicate this process. Shock results in decreased
blood pressure, which speeds up the inevitable course of kidney failure.
Other injuries may cause blood loss on top of a lower blood pressure. Any chest injury can lead to breathing difficulties.
Not enough air
Some people die because they are trapped under rubble in a small space with limited quantities of air.
The human body is very vulnerable yet also amazingly resilient, and
miracles do happen. There have been many instances where survivors have been plucked from the rubble many days after a disaster.
(Health24, updated 2013)
(Photo of tornado from Shutterstock)
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