The question of human longevity has gradually come to the attention of mankind since the turn of the century, and it is important to realize that this proposition did not exist in the days of early man when the basic demands of food, clothing, shelter and transportation were not yet fulfilled in most of the human territories. It is feared that the wild nature allowed early man to experience 'a thousand ways to die' before human activities tended to settle down and stabilize. Human longevity seemed to humans at that time to depend more on one's creation and luck, and some Western religious scholars believe that this was one of the reasons for the itinerary of the first primitive religions and beliefs. With the initial deepening of the urbanization of human civilization, we gradually realized that even living in peaceful times, the twin siblings around us still died years apart, which aroused great interest in life span. Gradually, various research experiments, disciplines, and doctrines on human longevity have been developed in different ways around the world. The secret of human longevity has become one of the top ten unsolved mysteries of the twentieth century, as the ultimate key to discovering the meaning of human immortality.

We can't completely discuss the factors that influence human longevity from all angles, because it even includes too many factors such as sleep, genes, gender, happiness index, living environment, living habits, marital status, education level, and history of medication, which involves a wide range of fields and disciplines that are so comprehensive that it puts people to shame. Big data era under the overwhelming statisticians let us have a new understanding of life expectancy from various interesting angles, the U.S. "Nature" magazine even 25 years ago statistics on the life expectancy of left-handed people and normal people compared to the surprisingly left-handed than the average life expectancy of normal people will be about 3.7 to 8 years less. This data may make famous left-handed former U.S. President Barack Obama sweat.

Given the diversity and responsibility of the factors affecting life expectancy, this article will only discuss in depth the impact of the climatic environment, especially temperature, on human life expectancy. Australian media personality John Johnson has done statistics that the average lifespan of all the Earth's population in the tropics is 64.4 years, while the average lifespan of all the population in non-tropical areas is 72.1 years. Of these, the total population of the tropical region (including about 144 countries or regions) accounts for about 40% of the world's population, and the rest of the population accounts for about 60%, and the International Population Federation expects that by 2050, the total population of the tropical and non-tropical regions will reach a convergence of 50% each. At first glance, most people living in the tropics are in a hot and rainy environment all year round, with a relatively fast basal metabolism and rapid cellular aging, as if a short lifespan is deserved, however, is this really the case?

Let's look at some data:

According to a report by the University of Nairobi in Kenya, the average life expectancy in the tropics increased steadily from 41.6 years to 64.4 years from 1950 to 2010. During the same period, the neonatal mortality rate in the tropics declined from 16.1% to 5.8% (the neonatal mortality rate in the non-tropics has been as low as 3.3% during the same period). Women in the tropics generally live longer than men, and this gap has continued to grow over the last six decades, with the difference in life expectancy between the tropics and the non-tropics of 12.6 years in 1950 narrowing to 7.7 years in 2010. It is important to note that average life expectancy can be calculated in a number of ways, the more common being the average life expectancy of people born in the same period, calculated as the sum of all life expectancy divided by the number of people in that period. This will also include dead newborns, but most will not count aborted babies as newborn deaths.

To address the effect of climate on life expectancy, a team of biologists at the University of Michigan has experimented with insects, which they put into cold environments, resulting in a significant increase in life expectancy for insects in cold environments compared with their counterparts in normal environments. Recently, the University of California conducted further experiments with rats, and the results showed that cold environments could extend the life span of rats by about 20%. However, anthropologists have experienced insurmountable difficulties in extrapolating the results of these experiments to humans. Humans, as complex organisms, operate differently from simple single-celled organisms and lower animals, and while we know that low temperatures do reduce metabolism, the relationship between metabolic rate and life expectancy is far more complex.

As a simple example, many tropical countries near the equator have low levels of urbanization, poor sanitation, poor living conditions, diseases that are often not effectively controlled, and frequent wars, all of which are unnatural factors that undoubtedly contribute to human longevity in the tropics being unaffected by a single variable of temperature and climate. If one were to try to control the other variables that affect human longevity, one can only imagine what an experiment in human morality and ethics this would be, feasibility aside.

An interesting counter-example, Singapore is located in the tropics, and according to data released by the World Health Organization on May 15, 2016, its national life expectancy is 83.1 years, the third highest in the world (with Singaporean women's average life expectancy at 86.1, a full six years longer than the average life expectancy of men). On the contrary, when mentioning the cold zone people usually think of the first fighting nation Russia, according to the World Health Organization in 2016, its average life expectancy for men is only a staggering 64.7 years, the average life expectancy for women is 76.3 years, and the combined average life expectancy is 70.2 years. The fighting nation lives up to its name, with men living on average about 12 years less than women, which is already a round worse in China. That's why Medvedev advises male citizens to always drink alcohol in moderation, especially vodka, yet just as parts of southern China still retain the tradition of eating wildlife and insects, Russia's cold has kept the habit of brewing, drinking and drinking high numbers of alcohol from a long time ago, which is almost unavoidable in colder places. But even comparing just the average life expectancy of women in Singapore and Russia, the difference is still close to a decade.

Summarizing the above, we have come to a conclusion that shatters the notion that people in the cold zone live longer than those in the tropics. We often hear elders lament that some people smoke and drink all their lives and still live long, while others who never smoke or drink and love sports die early, as if all the so-called secrets of longevity are just empty talk. Indeed, the influence of genes on human life expectancy can be said to be not to be underestimated, but the acquired habits still have an irreplaceable role. Look at the living habits of Japan, the country with the longest life expectancy per capita in the world, it is not difficult for us to understand the reason. The current President of the United States, Donald Trump, was elected at the age of seventy, an age that itself has far exceeded the average life expectancy of men in many countries, so the proposition of human longevity is really intriguing. Perhaps mankind should spend more energy understanding the mysteries of ourselves first before spending huge sums of money exploring the universe.

Article source: Baidu Knowledge Daily (/daily)