The Simple Science Behind Dehydration

How Does Dehydration Affect Us

Many people take dehydration for granted. Most people do not even know that thirst is the first indicator of dehydration. Dehydration affects different people in different ways. A lot of factors have to be taken into account when discussing dehydration.

For example, you have to take into account how active the person is, what is the current temperature of the location the person is currently in, and how much they are sweating. The most obvious example people think of is getting stranded in the desert. The truth is a person can get dehydrated even in mild climate conditions if they overexert themselves and if they do not watch how much water they are taking in.

The Stages of Dehydration

You can separate dehydration into four stages. These would be thirst, followed by fainting, organ damage, and then finally death.

In the first stage, thirst, the total amount of body weight you lose due to water loss is about two percent. This means that a person that weighs 170 pounds ends up losing three pounds. A plain cardio exercise lasting about an hour is enough to cause a loss such as this.

The body combats this by holding on to any remaining liquid it has. This means your kidneys start to hold water instead of sending it to the bladder. For this reason, a person’s urine gets darker in hue. Also, the core body temperature rises since a person is sweating less when dehydrated. Blood gets thicker, and the heart rate increases in order to stabilize oxygen levels.

The next stage a person encounters is fainting. At this point, the person has lost about four percent of their body weight. That means if a person weighs 170 pounds, they are losing about seven. You could replicate this by riding a bicycle for three hours at high temperatures. Another way would be not drinking water for two days.

At this point, the person’s blood is so thick that their skin starts shriveling. The blood pressure gets so low that they become susceptible to fainting. Because of the water loss, the person stops sweating and is effectively starting to overheat.

The second to last stage is connected to organ damage. The person has lost seven percent of their body weight. That means a loss of 12 pounds for a person that weighs 170 pounds. You could achieve this by doing yoga or other stretching exercises without hydration for eight hours.

Now the body is starting to have trouble maintaining its blood pressure. As it goes into survival mode, the body slows down blood flow, especially to the non-vital organs and causes damage to them. At this point, you are basically dying for a sip of water.

Finally, in the fourth stage, the person has lost 10 percent of their body weight. That is a whole 17 pounds for a person that weighs 170. A person could achieve this by not drinking water for five days straight.

At this point, a person needs to drink water as soon as possible. The person’s body temperature at this point is so high that the organs are overheating. The most probable outcome is death from liver failure. And even if you were in a milder climate a person may die from kidney failure.


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