Scientists have explained why women live longer than men.
The main reason for women’s longevity
Shorter life expectancy and higher risk of mortality characteristic of the males of many species. In the course of natural selection are not more important than health and longevity, and the characteristics that ensure reproductive success or, in the language of biology, fitness.
Adaptability is more important than longevity
Adaptability is the ability to reproduce. If the benefits of increased fitness outweighs the consequences of the loss of life expectancy, nature makes a choice in favor of fitness. The impact of this can be clearly traced among women: pregnancy, childbirth and breastfeeding are physically exhausting and takes a lot of energy. According to research, the more female children are born, the higher her body’s level of oxidative stress, and this leads to accelerated aging after menopause. Same with testosterone can be described as hormone generated by the body. Testicles produce it in the case of men, and ovaries in the event of women then should know about low T clinic. Many people usually think of low testosterone as men’s problems, but it is also observed in the development of women.
Although men do not have to endure the hardships of pregnancy, they also spend a lot of energy on reproductive efforts that affect them in old age.
Such efforts include risky behavior, and greater accumulation of body mass, namely, specific skeletal muscles, which is characteristic only for men (the muscles on the shoulders, back, arms). The price paid for it from the point of view of a metabolism comparable to the flow of energy that women experience during pregnancy and lactation.
Nature has developed special physiological mechanisms to control a connection between fitness and life expectancy. And hormones one of the main factors responsible for this. In men, muscle mass and reproductive behavior regulates the hormone testosterone.
What does testosterone in the body
Testosterone promotes lean muscle mass and speeds up metabolism, triggers fat burning. In addition, he is responsible for the growth of facial hair and lowering of voice, and can enhance libido and mood. It seems to be all that useful, but have high levels of testosterone and negative consequences.
Of course, you prefer to look at myself in the mirror when you have no excess fat, but in the wild the lack of fat reserves makes you more vulnerable to infection or lack of food. This vulnerability is characteristic of many species, in which a sharp rise in testosterone levels serves as a signal to increase reproductive effort.
For example, severoevropeyskikh marsupials Martens. The males of these animals is a sharp one-time increase in testosterone that triggers mating, and significantly increases mortality due to aggression between males and exhaustion. Females of the marsupial weasels live up to three years, and males don’t always live up to a year.
Something similar is observed in birds. Ornithologists have noticed that with artificially elevated testosterone males successfully repel rivals and produce more offspring compared to individuals not receiving additional hormone. But although their reproductive fitness is higher, they have reduced survival. Birds with artificially elevated testosterone levels gain less weight and don’t always survive the mating season.
The negative effect of testosterone
The effect of testosterone on the human body is less straight forward and harder to measure. Yet you can’t exactly say that men who take testosterone, live on less evidence appear.
Thus, according to held in 2014 the study, older men taking testosterone, increases the risk of nonfatal myocardial infarction. Yes, elevated testosterone helps build muscle, but other organs at this age have a hard time with this load.
Testosterone also affects the immune system.
Men are often harder to fight infections than women, because testosterone suppresses the immune system, while the main female sex hormone, estradiol, it strengthens.
The latter, however, also increases the risk of developing autoimmune diseases — this is another compromise, which is nature ready to go in exchange for the use of estradiol for reproduction.
Moreover, levels of testosterone and other sex hormones is associated with an increased risk of developing cancer, especially prostate cancer.
The way out of the situation
Why is nature still allows it?
Other mammals are ready to make expensive testosterone and risk because the potential benefits of adaptation for all kind is very high.
However, this does not mean that there are no other options. People have developed alternative reproductive strategy of paternal contribution to fitness of offspring, which is rare among other primates (and all mammals).
To take care of their offspring, the father should spend more time with him, so risky behavior goes by the wayside, the level of testosterone decreases, and this is, quite possibly, increases life expectancy. So to some extent fatherhood is good for health.
Of course, testosterone is still need men for reproduction. And it is unlikely that people will once get rid associated with this hormone problems. But whatever it was, to be a man is still better than the marsupial marten.