Let’s say you’re a guy, and you’ve done just fine so far. Why should you think about changing your ways to fit in with women? It seems absurd even to consider the possibility.

“Ladies (women? gals? Hell, I don’t know!) you need to man up if you want to succeed in a man’s world,” one Wall Street Journal reader wrote after I suggested in an article that men try to better understand women.

As another male reader put it, “Women need to learn the way men interact, and change themselves accordingly.”

Actually, women already change themselves plenty. If you’re a man, here are a few things you should know. I wear high heels at work because I’m convinced that makes me look more powerful to you. (Research tells me I’m right—taller women earn as much as 8 percent more than shorter ones). Linda Hudson, former chief executive of defense contractor BAE Systems, hired a drama teacher so she could get rid of her Georgia accent and lower the pitch of her voice, to sound more like you. Dr. Carmen Quatman, a chief orthopedic surgical resident at Ohio State University, sought out coaching to look as confident as you—as if it wasn’t enough that she’d already published 20 papers, presented at 17 conferences, and won 6 national awards.

All of us, and countless other women, are attempting to fit into a professional world that was created in the image of men. The way we speak, dress, write emails, present ourselves—we’re conscious of how we come across in a culture that’s not quite our own. We’re always a little bit like a tourist, trying to mimic the habits of the locals so we can blend in. New York Times reporter David Streitfeld perfectly captured the impossible balance many women are trying to strike in a piece he wrote about a sex discrimination suit: “Speak up—but don’t talk too much. Light up the room—but don’t overshadow others. Be confident and critical—but not cocky or negative.”

That’s one reason why women have been so intrigued by social psychologist Amy Cuddy’s work on power posing. She’s found that we can improve our confidence and actually increase our testosterone levels—literally appear more like men—by adapting simple “power poses,” like standing arms akimbo with hands on hips and legs wide (the “Wonder Woman”), putting our legs up on our desks, or puffing out our chests. The poses not only increase testosterone levels by as much as 20 percent, they also decrease stress levels.

Not surprisingly, these poses come naturally to men, but they are foreign to most women—not to mention difficult to pull off in a pencil skirt and heels. We do them anyway.

We change our appearance to fit in with you too. A woman’s looks sometimes count more than her résumé. One study found that women with blond hair earn 7 percent more than brunettes. Women who wear makeup get better jobs and quicker promotions. Thin women outearn heavier women; white women who are overweight pay a financial penalty of a 12 percent drop in their wealth. Multiple studies have found that people of both genders who are more attractive than average earn more money than their less genetically gifted peers. But there too men have the edge: when researchers interviewed fourteen thousand people, they concluded that for women, grooming—hair, makeup, clothes—counts even more than looks when it comes to earnings.

Take it from me, it costs a small—make that more like a large—fortune for all that upkeep. The average woman spends $15,000 on cosmetics alone during her lifetime. And that’s just for starters. Women pay more than men for almost all of their necessities, from dry cleaning to razors to shampoo to blue jeans. It’s known as the “pink tax,” and it’s pervasive. The New York City Department of Consumer Affairs found that 42 percent out of eight hundred products it surveyed cost more for women than for men. That can add up to $1,400 a year for women, a California study found. Considering that women earn less than men for the same jobs in the first place, the financial consequences are severe.

Depending on where you work, the costs can be even steeper. The fashion, advertising, and hospitality industries are particularly brutal for women. When I was an editor at Condé Nast, a publisher known for magazines like Vogue and Glamour, every item of clothing, pocketbook, and pair of shoes I wore was scrutinized, even though I worked at a business publication and didn’t even share the same elevator bank as the fashion editors. Walking into the company cafeteria, with a sea of eyes staring you up and down, could turn into an exercise of doubt and self-flagellation.

Early on, some colleagues in the photo department kidnapped me, on a “mercy mission,” they said only half-jokingly, to save me from myself. Apparently, my amateur makeup application looked “too New Jersey.” (Though being born and raised in New Jersey, I didn’t consider that an insult.) They brought in a makeup artist who promptly threw out the drugstore mascara and eyeliner I’d been using since I was twelve years old, and loaded me up with expensive designer cosmetics.

All those extra costs don’t even include the hours women spend on styling our hair, getting manicures, and putting on makeup. One of my favorite examples of how this plays out comes from the former president of Barnard College, Debora Spar, who in her book Wonder Women: Sex, Power and the Quest for Perfection calculated that she spends 282 hours a year on basic maintenance, versus the 30 hours that her husband spends. “Over the course of a forty-year career, I will spend 10,080 more hours than the average guy sitting next to me—nearly five working years—trying to make myself look presentable,” she wrote.

That’s a sobering thought, that women need to cram in five extra years over the same time period of our careers just to stay on par with men. And that’s before considering the additional time women spend on child care and housework, which despite admirable gains that men have made in these areas over the past generation, still clocks in at about nine hours a week more than men spend.

Women in positions of authority make even more changes, so that they don’t appear too threatening to you. One study found that 48 percent of female CEOs and 35 percent of female senators have blond hair, even though only 5 percent of the white population is blond. Hillary Clinton, who in her student days appeared to be a brunette, has long since become blond. Sandra Day O’Connor, first female Supreme Court justice? Blond. Meg Whitman, chief executive of Hewlett Packard? Virginia Rometty, chief executive of IBM, and Kirsten Gillibrand, New York senator? Yep, they’re blond too. Researchers theorize that lighter hair color is associated with youth, beauty, and warmth, which helps counteract the harsh trait of aggressiveness, which goes against female stereotypes.

Women even change the way they speak to fit in with you. Linguists have documented what most of us have observed in real life: men typically have speech patterns that are more assertive and aggressive, while women tend to be more inclusive and self-effacing. I am reminded of that every time I attend the Matrix Awards luncheon for women in media. Each year, on a Monday in April, a Manhattan hotel ballroom overflows with female television anchors, executives, writers, tech pioneers, and actresses. Onstage, either being honored or presenting awards, are some of the most accomplished women in the country, from Tina Fey to Toni Morrison to Katie Couric.

The honorees each give a short acceptance speech. And almost every one of them, in some form or another, says the same two words: “I’m lucky.” At one awards ceremony, even honoree Lena Dunham, the actress and very model of modern feminism, proclaimed how “lucky” she was—twice.

When men succeed, they attribute it to their own grit and intelligence. Women attribute it to luck. It’s hard for us to own our accomplishments. We diminish them, or refuse to talk about them, or give the credit to somebody else. We apologize all the time, even though we aren’t sorry. We lard up our work conversations with qualifiers like “This may be a stupid question, but . . .” or “I don’t want to bother you, but . . .” We make statements that sound like questions, even when stating facts (“Shouldn’t we turn right here, not left?”). We use language that makes us seem hesitant, that downplays our own status, and that implicitly cedes more power to the other person in the conversation—especially if it’s a man.

We also are highly aware of this, and are trying desperately to change it. We know that to men, our natural speech patterns can be misconstrued as a sign of weakness or indecision.

Comedian Amy Schumer spoofed the tendency for women to apologize in a hilarious skit in which the women speaking on a “females in innovation” panel, including a Pulitzer winner and a Nobel prize winner, trip over each other as they apologize for increasingly absurd scenarios, culminating in one of the women being fatally burned by scalding-hot coffee spilled on her by a man (“Sorry, is this coffee? Sorry, this is my fault”). It wasn’t that far off from the truth; Hilary Clinton became the first presidential candidate in recorded history to say “I’m sorry” in her concession speech.

So we try to erase our own natural speech patterns, to sound more like you. Some female executives keep a “Sorry Jar” on their desks, contributing a dollar each time they find themselves uttering the word. Google even offers a gmail plug-in for women called “Just Not Sorry.” It highlights those undermining words and phrases with a red underline, as if they are misspelled. It is a reminder to women to stop sabotaging ourselves in your eyes.

All of this is simply to fit in with you, to be as unobtrusive as possible so that we can be recognized for our work, and not penalized for the way we dress or speak or look or act. It takes hours of effort and hundreds of tiny daily conscious and subconscious decisions about what to say, when to speak, what to wear, whether to acknowledge we have a sick kid at home—moves we make to protect ourselves and that are completely invisible to most men.

My point isn’t to blame men, who for the most part don’t realize any of this is happening. I’m simply stating the facts. This is the reality for the women who work with you.

From the book THAT’S WHAT SHE SAID: What Men Need to Know (and Women Need to Tell Them) About Working Together by Joanne Lipman. Copyright © 2018 by Surrey Lane Media, LLC. Reprinted by permission of William Morrow, an imprint of HarperCollins Publishers.