On a hot summer’s day, one tends to drink cold drinks and eat cold foods to try cool their body down. But an old Korean proverb states that one should control fire with fire (yiyul-chiyul, 이열치열, 以熱治熱). In other words, instead of drinking cold drinks, it is better for your health if you eat hot soup to combat the heat. When the temperature becomes hot, the body redirects blood flow to the skin to cool itself, meaning there is less blood flow to the organs and causing the internal temperature to drop. Although cooling yourself is good, having a cold drink rapidly on a hot day can suddenly cause a large temperature difference between the surface and the organs, leading to digestive problems. In severe cases, it can cause abdominal pain and diarrhoea, with a vicious cycle where the heat is trapped on the surface and you feel even hotter. Ergo, having a hot food like samgyetang (a Korean chicken soup with many nutritious foods to revitalise your health in the summer) warms the organs and allows for better communication between the organs and the skin to effectively overcome the heat.
The philosophy of yiyul-chiyul can be extended beyond the scopes of medicine. Just as the proverb defeat savages with savages (yiyi-jeyi, 이이제이, 以夷制夷) says, one can control a certain force by using the same force on it. A great example is backfires. A forest fire tends to be too large in area to be extinguished with water. But if you deliberately start a fire just beyond its trajectory, it will burn everything as it moves towards the forest fire. Eventually the two fires will meet and without any fuel to consume, both will be extinguished.
A person’s body temperature is always maintained between 36.5~37.5°C. This is because enzymes, which are crucial in all physiological reactions in the body, work most efficiently at this temperature. As physiology is essentially a series of chemical reactions, it is heavily dependent on temperature. If the temperature falls, chemical reactions occur slower and vice versa. When body temperature falls below 35°C, metabolism becomes too slow and it poses a risk to the person’s health. This is known as hypothermia.
How does hypothermia affect the body? Hypothermia is categorised into three classes depending on the severity.
- Mild hypothermia (32~35°C) leads to the slowing of bodily functions, tremors and difficulty in walking. The patient’s speech is impeded and other neurological symptoms such as decreased judgement skills and confusion start to appear. Also, blood pressure, pulse and breathing rate rise.
- Moderate hypothermia (28~32°C) causes paralysis of muscles and extreme fatigue (they may complain of being sleepy). As blood (carrying heat) is rerouted to major organs, the skin (especially lips and extremities) become white or purple and very cold. Neurological symptoms worsen with amnesia, memory loss, severe confusion and delusion beginning to show. As sustained hypothermia leads to the tremors stopping, one should not take the lack of tremors as a good sign. Heart rate becomes irregular and arrhythmia may occur.
- Severe hypothermia (20~28°C) leads to chemical reactions becoming so slowed that physiological functions that support life decline dramatically. Heart rate, blood pressure and breathing all lower to dangerous levels and the heart and lungs may stop functioning. As the patient’s major organs begin to shut down, they enter a state of unconsciousness and eventually, clinical death.
As you can see, hypothermia is a highly dangerous situation that can kill. There are some other fascinating facts about hypothermia.
20~50% of hypothermia death cases are associated with paradoxical undressing. This is a strange phenomenon where the person begins to take off their clothes due to confusion and a lack of judgement from the hypothermia. One theory suggests it is related to the cold damaging the hypothalamus (which controls body temperature), causing the brain to think that the body temperature is rising. Whatever the reason, it is extremely dangerous as it worsens the hypothermia.
As explained above, severe hypothermia leads to death. But interestingly, hypothermia also protects organs. This is why organs for transplanting are transported in ice. Similarly, there are examples of people who “died” from hypothermia recovering with no brain damage. Because of this, medical professionals traditionally say: “they’re not dead until they’re warm and dead”. In fact, if there is something wrong with the patient’s circulation and there is risk of damage to their organs (such as in surgery), sometimes the patient’s body temperature is forced down with ice water injections and cooling blankets, known as protective hypothermia.
In 1967, a group of scientists designed an experiment where five monkeys were put in one cage with a ladder in the middle and a banana suspended over it. When a monkey tried to climb the ladder to reach the banana, it was hosed down with ice cold water to discourage it. However, at the same time the four other monkeys were sprayed as well. This was repeated until the monkeys were conditioned not to climb the ladder as it meant being blasted by cold water. Interestingly, even when the reward was tempting enough for a monkey to brace the cold water and climb the ladder, the monkey was swiftly taken down by the other monkeys – fearing the cold water – and was punished by a beating. This further discouraged the monkeys from climbing the ladder even when the researchers stopped spraying the monkeys with water.
The researchers then substituted one of the original monkeys with a new monkey who had not been in the cage before. This new monkey immediately noticed the banana and started to climb the ladder. The other monkeys saw this and responded with rage, enforcing their unspoken “rule” of never climbing the ladder. The new monkey quickly learned that climbing the ladder was a bad thing.
The researchers substituted another original monkey for a new monkey and the same thing happened. They repeated this until all monkeys were replaced.
When they substituted the last monkey in (number 10), the cage was already filled with “new” monkeys who had never been hosed before, but nonetheless knew not to climb the ladder. When the monkey was punished for climbing the ladder, it gave an expression that seemed to question why he was being punished. The other monkeys did not know why; none of them had been punished with cold water and only knew that the other monkeys would beat him up. Even though none of them knew why the punishment was required, they dished it out regardless. The rule had been engrained into the mob, with each monkey following it without any logical reason.
We often see people who criticise others for being “sheeple” – people who blindly conform to the majority and follow someone like sheep do. They protest that as human beings, we have a right and duty to exercise free will, sticking up for one’s own opinions. However, according to an infamous experiment from the 1950’s, we know that human beings are bound by our natural instincts to be social creatures, obeying the collective will of the group we are in.
In 1953, Solomon Asch designed an experiment to study the power of conformity. He told participants that they will be taking part in a vision test with a group of people. They were shown a picture depicting lines of various lengths, asking which line on the right matched the line on the left:
It was a simple task of matching the line to another line of the same length with the answer being blatantly obvious. But as with so many psychological experiments, there was a trick. The group of “participants” were actually in on the experiment other than the one subject. During the experiment, the group would all put their hands up on the blatantly wrong answer instead of the actual correct one. How did this action affect the subject’s answer?
Although it seems clear that the answer is A in the given example, when in a situation where the majority of people put their hands up for “B” or “C”, up to 32% of the subjects gave the incorrect answer. No matter how large the differences were between the sizes of the lines, the results did not change. Although 32% is only a third of the study group, one must bear in mind that this experiment only looked at black-and-white scenarios of lines of different length. If the issue at hand was much more “grey” – such as an ethical dilemma – it can be extrapolated that the person would easily sway and conform to the majority opinion.
The reason for the level of conformity exhibited in the experiment is quite simple: it’s the one who is different that gets left out in the cold.
When you quickly eat or drink something cold, you experience a sudden onset of a painful headache. This is commonly known as brain freeze, or medically, a sphenopalatine ganglioneuralgia.
Although the cause is not perfectly understood, it is believed to be due to the coldness on the palate (roof of mouth) causing a sudden cooling and rewarming of the sinus capillaries, which causes them to suddenly constrict and then rapidly dilate. Dilation of blood vessels in this area causes pain due to receptors in the vessels. This phenomenon is similar to the cause of a flushed face when exposed to cold wind, and why it sometimes causes headaches.
The only way to prevent a brain freeze is to slowly let the mouth get used to the cold, warming the food or beverage in the mouth instead of quickly swallowing it. Warming the palate with your tongue is another effective way to shorten the duration of a brain freeze.
A sneeze is caused by the body trying to remove something that is irritating the nasal cavity. To do this, it contracts many respiratory muscles instantly to create a powerful expiration. This produces a gush of air and the foreign material at a speed of over 150km/h, which can spread saliva and mucus at a range of over 2m. Therefore, not putting your hand over your mouth during a sneeze is an easy way to spread infections like the common cold.
An interesting fact is that one cannot open their eyes during a sneeze. This is not because of the urban legend that the eyeballs pop out if the eyes are open when sneezing, but part of the reflex and powerful contraction of muscles. Also, pinching between the two nostrils very hard can stop a sneeze reflex successfully.
Lastly, although sneezing is usually due to breathing in an irritant, some people have what is known as a photic sneeze reflex (also called the ACHOO syndrome), wherein they sneeze when stare into bright light such as the sun.