Age affects everyone differently. Maybe you’re baby-faced and still get carded for R-rated movies at 27 (to pick a completely random example that certainly didn’t happen to me just last week). Or maybe you were habitually put in charge of buying the booze in 8th grade because you could already grow a full beard at 13.
At a more general level, there’s some research to suggest that men and women also age differently. The focus of said research is based on how men and women of the same chronological age (i.e., the number of years since they were born) exhibit differences in their physiological or biological age, which — according to Eileen Crimmins, a professor of gerontology at the University of Southern California — is the average age of people who have the same physiological profile.
That’s right: Your physical age is based on how old you seem.
According to Terry Grossman, writing for Everyday Health, scientists have discovered that one reason why some people appear to be younger than they actually are has to do with the length of their telomeres — a structure at the end of your chromosomes:
“At the ends of each of our chromosomes are tiny beads that prevent the double strands of DNA in the chromosomes from unraveling. These beads, also known as telomeres, can be compared to the plastic tips that keep the ends of our shoelaces from fraying. Every time that a cell divides, a telomere bead falls off from the end of the chromosome. It appears there is a direct correlation between telomere length and biological age.”
But telomeres don’t explain why men and women — both humans, last time we checked — age differently. The chromosomes themselves, though, might: One biological factor in why women tend to live longer than men has to do with the fact that they have a backup X chromosome in case one of their X chromosomes is screwed up.
“The genetic advantage of females is evident,” reports Scientific American. “When a mutation of one of the genes of the X chromosome occurs, females have a second X to compensate, whereas all genes of the unique X chromosome of males express themselves, even if they are deleterious.” In layman’s terms, since men only have one X chromosome, even potentially harmful genes on said chromosome are going to be used during gene development.
Furthermore, female hormones — such as estrogen which, yes, men have too, but not as much — also help increase a woman’s life expectancy: “Estrogen, for example, facilitates the elimination of bad cholesterol and thus may offer some protection against heart disease; testosterone, on the other hand, has been linked to violence and risk taking,” reports the same Scientific American article.
Genetics and hormones aside, Crimmins says that historically speaking, women age slower than men simply because they take better care of themselves. “Women use more antihypertensives (drugs used to treat high blood pressure) and statins (medication used to reduce cardiovascular disease),” she says.
But based on a recent study conducted by Crimmins and Morgan E. Levine, a gerontologist at Yale, men are starting to catch up on this front. “Males, especially those in the youngest and oldest groups, experienced greater declines in biological age than females,” they wrote in their study. “Men still age faster but their improvement has been greater, so men and women look more alike now in their rates of aging than in the past,” explains Crimmins.
As for why, one major reason is cigarettes — or rather, the lack of them. “Men are smoking less,” says Crimmins. She’s right: According to the CDC, although more men than women in the U.S. still smoke cigarettes, the percentage of men who smoke today versus the percentage of men who smoked cigarettes in the 1980s has decreased more quickly than the percentage of women during that same time frame.
Which sounds like good news for men. That said, you might want to temper your expectations a little: Men are vaping more than women these days, so when that inevitably turns out to be terrible for us, we may well see that gap start growing again.