Читать книгу Age - Suresh Rattan - Страница 6

At a global level, the average life expectancy of human beings has been increasing steadily from less than 25 years in ancient times to about 71 years in 2016. This does not mean, however, that the average lifespan does not vary among countries and among different groups within a country.

According to present-day statistics, Monaco is the country where people can expect to live the longest – 89.57 years – whereas in Chad the average life expectancy is just 49.44 years. We could also focus on men and women separately. For example, in Denmark, at present, men live an average of 76.68 years, while women live five years longer.

A multitude of factors affect life expectancy, such as how many children die in the first five years of life; how many women die during childbirth; how many people die due to infectious and other diseases and due to natural and man-made catastrophes.

The important question is, of course, whether this historic increase in lifespan will continue forever, or whether it has reached its maximum? Biologists and other scientists are divided into two groups on this question. One group holds the position that, considering the ongoing developments in health-care technology, life expectancy will continue to increase and will surpass 100 years within the next ten to fifteen years.

The other group of scientists, especially biologists like myself, hold a different view. An increase in life expectancy cannot continue indefinitely, because soon we will face the realities and limitations of life’s biological processes.

We can try to imagine what a never-ending improvement in, say, race results at the Olympic Games would imply. Over the past 100 years, the clock time spent on covering almost all distances has been decreasing. If, based on this fact, I assume that these shorter clock-times will continue into the future, then by the year 2200, all races will be completed as soon as the starting shot is fired.

Obviously, this is absurd and nonsensical. Even the Jamaican sprinter Usain Bolt and the cartoon character Speedy Gonzales are not that fast. Sooner or later, we all have to face and accept the limits of our biology.

Therefore, my fellow biogerontologists and I reckon that our average lifespan will stabilise at about 90 to 95 years. Even this limit is still a long way into the future. There are still too many social, political and economic factors that prevent everyone, around the world, from achieving such a ripe age.