The boundary between life and human death

How spicy can you eat? How many bees will cause you to die? What sound is too loud for humans? The BBC Focus Magazine has conducted a series of experiments to understand our physical limitations. Try exploring.

1. How low can a human's body temperature be?

Body temperature varies for each person but is usually over 37 degrees C.

At 36 degrees Celsius, reflexes and judgment will be affected. At 35 degrees C, you can't write your name and travel hard. With 33 degrees Celsius, you can completely lose your mind. At 32 degrees C, most people will have a stroke, eventually become unconscious when the temperature drops to 30 degrees C. At this point, the body is no longer able to maintain body temperature. Breathing drops to just 1-2 beats per minute.

At 28 degrees C, arrhythmia will occur and by the time you are 20 degrees C, your heart will stop beating completely. But then you're still not dead. You can survive by slowly warming up and using a timely defibrillator.

However, the lowest limit is 0 degrees C. At this temperature, ice crystals will form in the tissue, destroying all cells.

Theoretical limit: 0 degrees C
Current record: 16 degrees Celsius

2. The strongest punch

Muscle tissue produces about 0.3 micronewtons of force on each muscle fiber. This is equivalent to 100 Newtons (10 kg) per cm2 on your body. But the bones on the forearm will dissipate about 200 compressive megapascals, equivalent to a force of about 50 kilonewtons.

If we assume that the arm muscles contribute half of the punch (the rest comes from the legs, hips and shoulders when coordinating at the same time), then you will need a triceps on the upper arm with circumference 55 cm to achieve this limit, as well as a lot of practice to maximize the technique.

Theory limit: 50 kN
Current record: 3kN

3. How much blood can you lose and still live?

A healthy adult has between 3.8 and 5.6 liters of blood. You can lose up to 15% of your blood volume without any immediate harm. But the heart rate will be faster, you feel dizzy, uncomfortable and cold. When you lose 40%, your blood pressure will drop, causing blood to flow slowly to the ventricles, and the heart will beat rapidly.

If you have a healthy cardiovascular system, you will increase your chances of survival. Lying still, calm will help delay the shock by reducing the amount of adrenalin.

Theoretical limit: 1.9 - 2.8 liters ~ 50%
Current record: 75%

The cartoon characters in Incredibles are not subject to any restrictions.(Photo: Dailymail)

4. How much water can you drink in 1 hour?

10 liters: That's the maximum amount of water you can drink in 1 hour without diluting the electrolyte content. Otherwise, you will have a stroke or death.

5. How long can you eat a spicy curry?

The active ingredient in curry or chili is capsaicin. The more capsaicin, the more spicy curry. Tabasco sauce usually has about 260 parts per million (ppm) capsaicin. Cuban peppers contain about 17,000 ppm. In theory, the most spicy curry you can eat is a bowl of capsaicin. It will be 10,000 times more spicy than Indian vindaloo.

Although capsaicin does not burn or damage tissue, its effect on the nervous system is similar to that of allergies. In addition to the pain, you will feel hot eyes and nose, limbs twitching and difficulty breathing for about 30-45 minutes.

If you are healthy and have never had heart disease or asthma, you can still survive after eating a spoonful of pure capsaicin, but you will not be able to eat anything else for several hours.

Theoretical limit: 5g capsaicin
Current record: 0.1 g

6. How many balls can you juggle?

A human hand can handle 11-12 balls, no one can do with 13 balls. The problem is that the more balls in the air, the faster your hand will be to keep them from falling to the ground.

7. How fast can you run?

Determining this is complicated. Even to know who is the fastest runner today is very difficult.

The current world record for 100 m sprint is by Jamaican Asafa Powell. She achieved 9.74 seconds in 2007. That is equivalent to an average speed of 36.96 km / h. But because the runner comes from a standing posture, it includes acceleration time.

The 200 m sprinter will complete the second 100 m section in a shorter time because they are already running at maximum speed when crossing the 100 m mark.

Theoretical limit: 43.06 km / h
Current record: 42.52 km / h

8. How many bees can you survive with?

2,243 is the largest number of bee stings a person has ever survived.
600 is the theoretical limit for a person to have 50% chance of survival.

9. What kind of sound is too loud?

At 125 dB (a jet takes off at a distance of 50 m), the sound has become too loud, painful.

The loudest sound that you can safely hear is 160 dB because if this excess, your eardrum will be punctured.

The biggest sound ever recorded was the volcanic eruption Krakatoa in 1883, reaching 180 dB, at a distance of 160 km. Anyone within a distance of 20 km must have suffered 200 dB of sound and then, pressure will break the lungs, pushing air into the bloodstream, causing death.

Theoretical limit: 200 dB
Current record: 175 dB at a distance of 2 m.

10. As long as the electric shock is strong, can you still live?

According to the classic electric shock method, the shocking heart causes it to stop beating. Then it is not lethal voltage but current, in amps.

The human tolerance threshold is 1 mA, while the 200 mA current can stop the 300 g heart, causing death.

According to Ohm's law, current flowing through a conductor is calculated by the voltage divided by the resistor, using ohm units. The resistance of human skin varies from 1,000 ohm (wet skin) to 100,000 ohm (dry skin), so lethal voltage will be 200 V and 20,000 V respectively.

Theoretical limit: 27,000 V
Current record: no

11. How big can you endure a car crash?

At a speed of 48 km / h, the ability to survive a crashed car dropped to 27%. At speeds above 60 km / h, your survival rate is less than 1%.