Women all around the world can rejoice about one survival advantage: they outlive men. In the United States, the survival rate for females is 81.2 years compared to 76.4 years for males, despite being afflicted by health conditions as they age. So, why do women outlive men, and is there anything men can do to boost their life expectancy?

In SciShow's latest video, "Why Do Women Live Longer Than Men?" host Michael Aranda explains there are a few theories that rely on social and biological differences to distinguish between biosex females and males, or those who have XX or XY chromosomes.

Theories from the 1970s or earlier suggest men are more likely to have work-related injuries and stress, which can lead to heart disease; or men tend to do more unhealthy things, like smoke cigarettes or drink heavily. However, these social trends vary across cultures, and don't explain everything. It's hard to study male and female longevity in animal models, because other mammals, such as primates or mice, don't always show the same trends as humans.

Therefore, scientists think it might have more to do with biological differences. One possibility is that genes on the X chromosome may affect longevity, but they have so many other biological effects that it's hard to tell. For example, chromosomes come in pairs, and whereas women have two X chromosomes, men have an X and a Y chromosome. Having two X chromosomes means women keep double copies of every gene, so there’s a spare if one is faulty. Men don’t have that back-up, which could put men at a greater risk for disease.

Other theories include the influence of sex hormones on longevity. Two small studies — one looked at longevity records in 16th to 19th century Korean Royal Courts, and the other examined records from a 20th century U.S. mental hospital — found people who were born male and had their testicles removed lived longer lifespans than other males.

Although adult women do live longer, they tend to to have worse health as they age, especially bone and joint issues. It's believed these later-in-life health issues, combined with different hormones, give women a paradoxical advantage — their health problems might activate immune responses, which protect those joint tissues, and that could ultimately lead to a longer life.

This biological mystery does exist, but scientists still need to do a lot more research on people of all sexes and ages to solve the puzzle. 

In the meantime, men should target the biggest killers, including high blood pressure, heart disease, and tobacco to boost their life expectancy.

High Blood Pressure

Men with high blood pressure should opt to eat more lean meat. A study published in the  Journal of Human Hypertension found people with high blood pressure who replaced eight percent of their daily calories from bread, cereal, potatoes, or pasta with lean red meat had a four-point drop in their systolic blood pressure in eight weeks. This suggests a moderate protein diet that emphasizes lean beef as the main protein can reduce blood pressure compared to a diet that was lower in protein and higher in carbohydrates and saturated fat.

Heart Disease

A high-dairy intake can slash a man's risk of heart disease by about a third. A study published in the American Journal of Clinical Nutrition found consuming three or more servings of dairy per day can reduce heart disease risk, but researchers do not know how exactly this works. Other studies have shown calcium and magnesium can lower blood pressure.

Smoking

Cigarette smoking causes premature death, with the life expectancy for smokers being at least 10 years less than nonsmokers. However, Quitting smoking before the age of 40 reduces the risk of dying from smoking-related disease by about 90 percent, according to the Centers for Disease Control and Prevention. A study published in the British Medical Journal found smokers who saw their results from a saliva-based nicotine test were 17 percent more likely to quit. Seeing progress while trying to quit helped motivate the participants to not relapse.