Gone are the days when men went off to wars and women died during childhood. Medical science today has made it possible for humans to live far beyond what our ancestors would have thought possible just a few decades back.
The global average life expectancy today is 72.6 years. But oddly, women everywhere live longer than men. The average life expectancy of men, globally, is around 70 years whereas for women it is about 75 years. This isn’t just seen in humans. In many species like chimpanzees, gorillas, and other apes, females outlive their male counterparts.
Why do women life longer than men though?
Why is this the case though? The evidence is sparse and the reason for this is still unknown, there are some possible explanations that researchers have agreed upon. Some of these are quite obvious and straightforward. Some, however, are more complicated.
- Men smoke more often than women. This one is easy to understand. Smokers are obviously more prone to life-threatening diseases and medical conditions like cancer, diabetes, heart diseases. Smokers are also more likely to have a stroke and tuberculosis among other health complications. For example, In Russia, men are likely to die thirteen years earlier than women. This is because they drink and smoke more than women.
- More men die in road accidents than women. Men are more likely to engage in rash driving and other risky driving practices than women. Men are also more likely to drink and drive than women. This explains, in part, the reason why men have a shorter life expectancy.
- The Cancer mortality rate is higher among men than women. Women have oestrogen that helps them with blood clotting, increases the level of good cholesterol, and also maintains the gastrointestinal tract. Men have testosterone that stimulates the prostate gland and this results in an increased risk of prostate cancer. Oestrogen is also an antioxidant and is a factor in women’s longevity.
- Theory of Antagonistic Pleiotropy implies that while testosterone levels in men help keep us fit during the early years of life, the risk of prostate cancer increases in the later stages of life. Testosterone is likely the main factor as to why men are likely to die early than women. A study suggests that eunuchs, who have no testosterone, outlive men by a huge margin.
- Also, girls are born more robust and healthier than boys. This research from the royal college of surgeons in Ireland suggests that baby girls fare better than boys because of innate genetic advantages that help them against acute infections. Girls have the XX chromosomes whereas boys have the XY chromosomes. Studies show that the X chromosome is the one that contains infection-fighting genetic material. Thus, girls, with an extra X chromosome, fare better than boys.
- This study says that during the menstrual cycle, women’s heart rate increases. This increased heart rate is equivalent to the increased heart rate during exercising. So women are getting some moderate exercise every month! This means a delayed risk of cardiovascular diseases later in life.
Some studies also suggest that women are emotionally stronger than men, more likely to survive trauma and pain (physical as well as mental). In many species, women are the ones that take care of the needs of a newborn. So it seems that evolution saw merit in giving females a survival advantage. Whatever be the reason, we know that mother nature deemed it fit that women live longer than men.
Scientists have discovered answers to a lot of Hows but they may never get an answer to why do women live longer than men.