Why is hypothermia dangerous? It is dangerous because it is a fatal condition.
Hypothermia is often confused with hyperthermia. Hypothermia is when the human body temperature drops below 35 °C and hyperthermia is when the body temperature is above 37.5 °C. “Hypo” comes from Greek and means “under”. “Hyper” also comes from Greek and means “over”. “Thermia” means “heat”.
We are warm blooded animals, which means we can generate our own heat. We make our body heat in two ways. The main way is through our metabolism. We eat food for its energy. We convert these foods into proteins and sugars. We store the sugar as glucose until we need to use it for energy. When we need it, the glucose is metabolized into carbon dioxide and water, generating adenosine triphosphate through oxidization in our muscles. A byproduct of this process is heat. The second way is through friction. Our blood flowing through our veins generates heat as it rubs along the veins. Our muscles generate heat through friction when they move.
The body generally keeps in homeostasis. It produces enough heat to keep the body temperature at a normal level. Heat is produced in the muscles, and we lose heat through our skin. When we start to get colder, the body can increase the amount of glucose it metabolizes to produce more heat, keeping our body temperature where it should be. However, the body cannot do this indefinitely.
We have a number of automatic responses that are aimed at conserving heat when our body temperature begins to drop. When you start to lose heat faster than you can produce it, your body will begin to shiver. This is an automatic response. The body is contracting and relaxing the muscles in rapid succession to produce heat. This can save you if you can get out of the cold. If you can’t, your body temperature will keep dropping. Another thing that happens is that as the temperature drops, your blood circulation will decline as well. When we are cold, our bodies constrict our veins to conserve heat by reducing the amount of blood that can flow near the skin. This conserves heat, but it causes the blood pressure to rise, the heat rate to increase, and breathing to increase. When your veins constrict, it is more difficult to get blood and oxygen to the brain, so confusion is quite common as well.
As the body temperature continues to drop, the blood is shunted away from the extremities to keep the core and the organs warm. This is called peripheral vasoconstriction. A consequence of this is that we need to urinate more often when we are very cold. When a lot of the blood is in the core, it increases the fluid volume. The kidneys sense the extra fluid volume, and they try to get rid of extra fluid to balance it out.
If the temperature keeps dropping, people may experience more confusion, slurred speech, decreased reflexes, and loss of fine motor skills. These are all caused by the lack of blood and oxygen to the brain. A person with a body temperature of 28 °C will have a heart rate of about 30 beats per minute. Shivering will stop when the body temperature falls below 32 °C. People will become very sleepy. As the blood pressure continues to fall death will be caused by heart failure.
When people are in severe stages of hypothermia, there is a common urge to remove clothing because they feel hot, which obviously just makes things worse. It is thought that this could be caused by the hypothalamus malfunctioning. This is the part of the brain that regulates temperature. It could also be caused by the muscles that are keeping the blood vessels constricted giving up. Blood would flow back to the skin, making the person feel hot.
People found in stages of hypothermia can be warmed up and saved. If someone is suffering from mild hypothermia, they can be warmed up using a blanket or hot drinks. Severe hypothermia needs hospital treatment. One treatment is to use warm humidified air that the person breathes in. This warms the body from the inside out. Warm saline solution can also be injected into the bloodstream. Some people can go into cardiac arrest when they are warmed up because of the shock.
There is a myth that people with hypothermia should be given strong alcohol, such as brandy, but this is not true and can make matters worse. People should be given warm, sweet drinks. The hot liquid can warm them up and the sugar will be needed for energy. And this is what I learned today.
Sources
https://tc.canada.ca/en/marine-transportation/marine-safety/hypothermia-survival-cold-water
https://www.medicalnewstoday.com/articles/182197
https://trustcarehealth.com/blog/hypothermia-explained
https://en.wikipedia.org/wiki/Shivering
https://www.labxchange.org/library/items/lb:LabXchange:ffe2c3ef:html:1
https://en.wikipedia.org/wiki/Warm-blooded
https://en.wikipedia.org/wiki/Hypothermia
https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682
https://www.cdc.gov/disasters/winter/staysafe/hypothermia.html