Have you ever felt like you don’t belong? Like your friends or colleagues are going to discover you’re a fraud, and you don’t actually deserve your job and accomplishments?

If so, you’re in good company. These feelings are known as impostor syndrome, or what psychologists often call impostor phenomenon. An estimated 70% of people experience these impostor feelings at some point in their lives, according to a review article published in the International Journal of Behavioral Science. Impostor syndrome affects all kinds of people from all parts of life: women, men, medical students, marketing managers, actors and executives.

What is impostor syndrome?

Impostor syndrome—the idea that you’ve only succeeded due to luck, and not because of your talent or qualifications—was first identified in 1978 by psychologists Pauline Rose Clance and Suzanne Imes. In their paper, they theorized that women were uniquely affected by impostor syndrome.

Since then, research has shown that both men and women experience impostor feelings, and Clance published a later paper acknowledging that impostor syndrome is not limited to women. (She also created an impostor syndrome test.) Today, impostor syndrome can apply to anyone “who isn’t able to internalize and own their successes,” says psychologist Audrey Ervin.

Impostor syndrome expert Valerie Young, who is the author of a book on the subject, The Secret Thoughts of Successful Women, has also found patterns in people who experience impostor feelings:

“Perfectionists” set extremely high expectations for themselves, and even if they meet 99% of their goals, they’re going to feel like failures. Any small mistake will make them question their own competence.
“Experts” feel the need to know every piece of information before they start a project and constantly look for new certifications or trainings to improve their skills. They won’t apply for a job if they don’t meet all the criteria in the posting, and they might be hesitant to ask a question in class or speak up in a meeting at work because they’re afraid of looking stupid if they don’t already know the answer.
When the “natural genius” has to struggle or work hard to accomplish something, he or she thinks this means they aren’t good enough. They are used to skills coming easily, and when they have to put in effort, their brain tells them that’s proof they’re an impostor.
“Soloists” feel they have to accomplish tasks on their own, and if they need to ask for help, they think that means they are a failure or a fraud.
“Supermen” or “superwomen” push themselves to work harder than those around them to prove that they’re not impostors. They feel the need to succeed in all aspects of life—at work, as parents, as partners—and may feel stressed when they are not accomplishing something…

One of the best perks of working at Health is that I'm lucky enough to test a lot of activewear. As a result, I've become very, very opinionated about leggings, and prefer different brands for different activities: supersoft Manduka leggings are my go-to for flights; Onzie leggings are lightweight, making them ideal for an outdoor run; and Visakai leggings, with their built-in underwear, help me flow through my weekly vinyasa yoga class.

Recently, though, I had the opportunity to try leggings from Core 10, Amazon's newest private athletic brand. The line includes both sports bras and tights, but it was their Build Your Own Bottoms that caught my eye. The tool lets you customize your own perfect pair of leggings by selecting the length, waistband, and style of your choice. Prices range from $59 for capris to $69 for full length. I went with the high-waist leggings in the 7/8 length.

To buy: from $59; amazon.com

My order arrived a few days before I was scheduled to go on a two-week vacation, and since I'd already packed most of the leggings in my regular rotation, I decided to debut the Core 10 bottoms on the five-hour flight. Let me tell you that they were incredibly comfortable—the perfect amount of stretch, a high waistband that sat comfortably on my midsection (no annoying digging!), and a fit that hugged my curves but never felt like my circulation was cut off.

RELATED: The 7 Best Workout Leggings With Pockets

They were so comfy, in fact, that I kept wanting to re-wear them throughout my trip, even though I had my other faves stashed in my suitcase. My Core 10 leggings carried me through multiple hotel gym workouts, a three-mile hike, and two flights (don't worry—I laundered them between wears).

There is one catch, though: The Core 10 line is a Prime exclusive, meaning you must have a subscription to the service to order them. If you aren't a member already, you can sign up for a 30-day free trial here.

This video is part of Health’s #RealLifeStrong series, where we are celebrating women who represent strength, resilience, and grace.

When Sydney Mesher tells people she's a dancer, they're often surprised, she says. The 20-year-old was born without a left hand, but that hasn't stopped her from pursuing her dreams in an industry known for its rigid body standards: "I get to be that person that kind of breaks that barrier, of that mindset."

Mesher’s left arm ends at the base of her wrist due to symbrachydactyly, a rare condition that causes the underdevelopment of limbs in the womb. "Growing up, I dealt with a lot of bullying," says the Portland, Ore., native. But she eventually recognized that the way people reacted to her was really all about them: "What's happening is someone's acting out of their own fear."

RELATED: Why This Ballerina With Panic Disorder and Depression Refuses to Apologize for Her Mental Illness

Mesher is currently studying dance at Pace University in New York City. "With dance you are constantly growing. There's no stopping point," she says. "There's always a place to be better." After college, she hopes to become a Rockette or a backup dancer for Lady Gaga.

“I’m very grateful that I’m at a time in this industry where we’re starting to accept different body types," she says. "I know I am different. Especially as an artist, it's so important to have those differences."

Her individuality shines through her work: "This is part of who I am. It’s not who I am, but it’s part of me. I want to share who I am and what I love, and celebrate that.” For more of Mesher's story, check out the video above. 

We want to hear about more #RealLifeStrong women. Nominate yourself—or a friend or family member—here. We’ll be sharing the most inspiring stories we receive in the months ahead.