Tag: life expectancy

Posted in Psychology & Medicine

Heartbeat Hypothesis

Posted on by Jinavie

When you compare the lifespans of mammals, it is common to see that larger animals live longer than smaller animals. Another observation is that smaller mammals almost always have a much higher basal heart rate. For example, a mouse has a basal heart rate of about 600 beats per minute (bpm), but only lives 3 years on average. An elephant has a basal heart rate of 30bpm, but lives up to 60 years. If you do the maths, it turns out that the total heartbeats per lifespan is surprisingly similar between the two species (0.94 billion beats). It has been noted that amongst mammals, there is a clear inverse correlation between heart rate and lifespan.

This observation led to the popularisation of a factoid that the heart can only beat a limited number of time before it eventually fails.

Unfortunately, there has been very limited evidence to support this theory. It is medically true that a heart under more strain for a long period of time, such as with high blood pressure, has a tendency to develop more diseases such as cardiomyopathy and heart failure. However, there are too many other variables to consider. For example, exercise temporarily raises your heart rate but improves your overall cardiovascular health and lowers your basal heart rate.

It is much more likely that death from aging is related to the basal metabolic rate. Metabolism produces free radicals, which are elements with free electrons that can damage cells. Therefore, the higher the metabolic rate (such as in mice), the faster the damage accumulates and results in death.

That being said, consider the other implication of the so-called heartbeat hypothesis. Our hearts beat faster in response to many stimuli: exercise, excitement, fear, anxiety, fun and love. If the hypothesis is true, that would mean that intense emotions could make our hearts tire out faster and hasten our inevitable demise.

Could falling in love be detrimental to our physical health? Thankfully, this has never been shown to be true, with many studies showing that happily married couples tend to outlive single people.

Even if it were true, would you give up on the idea of love to live a few more years? What kind of life would be worth living without any highs or lows? Perhaps when we fall in love, experience heartache or become overwhelmed with happiness, we are making the voluntary choice of quality, not quantity, of life.

Posted in History & Literature

Factoid

Posted on by Jinavie

Factoids are commonly known as trivial tidbits of knowledge and fact. This is actually incorrect. Factoids actually mean pieces of false information that have circulated and become popular to the point that they are accepted as facts. This makes factoids ironic in the sense that the definition of a factoid itself, is a factoid.

Here are several examples of common factoids.

“Vikings wore horns on their helmets”. 

There is no evidence of this ever happening and all Viking helmets found in archaeology are hornless. It is likely a myth originating from dramatisation of the Vikings in opera.

“Medieval people thought the Earth was flat”.

It has been common knowledge that the Earth is spherical even since ancient Greek times. Greek astronomer Eratosthenes even calculated the Earth’s circumference to within 5-15% error margin of the actual circumference in 240BC.

“Napoleon Bonaparte was short”.

Napoleon’s height was recorded as 5 feet 2 inches, but this is in fact French feet. This converts to 5 feet 7 inches, which is taller than the average height for French males at the time.

“The low life expectancy in the Middle Ages meant people usually died around their 30’s”. 

The low life expectancy of the past was mostly due to the high infant mortality, meaning people who survived into adulthood lived much longer, fuller lives.

“You need to drink eight glasses of water to stay healthy”. 

There is no agreed upon amount of water a person should drink in medical literature. The current consensus is that drinking water when you feel thirsty is fully sufficient to avoid dehydration.

“Carrots help you see in the dark”.

Vitamin A is indeed used by the body to synthesise chemicals used in vision, but having more does not improve your vision. This was a myth propagated by Great Britain during World War 2 to mask the fact that they were using radar for accurate nighttime bombings.

“Evolution is a theory, meaning there is insufficient evidence to confirm it”. 

This is a complete misunderstanding shared by many people against evolution. The word “theory” in science means a concept or set of principles that best explains an observed phenomena, not a hunch as it is often used in common English. For example, gravity is a theory, as well as germ theory (that microorganisms cause infectious diseases).

“Chameleons can change the colour of their skin to match their surroundings”.

Chameleon’s skin colours change based on their mood, not the colour of their surroundings. Cuttlefish, on the other hand, can perfectly mimic and blend in to their surrounding environment.

“Adding oil when boiling pasta stops sticking”.

The oil floats to the top and does nothing to prevent sticking. Adding oil after draining the water will help.

“Searing meat seals in the juices”.

Searing can actually make meat drier on average. It does, however, add more flavour by adding a brown crust due to the Maillard reaction.

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