A few years ago, Elizabeth Clor was trying—and struggling—to qualify for the Boston Marathon.

“I’d have bad experience after bad experience, and I’d get very anxious about it,” she says of trying to get into the race. (Most runners have to prove a very fast finishing time in order to gain entry.) “It became a self-fulfilling prophecy. Running, which started out as something fun, became this battle to prove to everyone that I was worthy of Boston.”

Clor decided to work with a sports psychologist, who helped her make a discovery that changed her relationship to running: “I was getting caught up in having my identity be as a runner,” she says. “That’s what a lot of my self-worth was based on, and I would get very depressed and frustrated when I wasn’t succeeding.”

With the psychologist’s guidance, Clor learned to think of herself not as a runner, but as a person who runs. This mindset shift “changed everything,” says Clor, making running more fun and less stressful—and ultimately helping her finally qualify for Boston, which she’s now done 12 times, and documented in her book, Boston Bound.

Clor’s experience isn’t an unusual one. So often, unlike other hobbies, fitness takes over our identities. We don’t just run—we’re a runner; we don’t just do Crossfit—we’re a Crossfitter; we don’t just hike—we’re a hiker. Our favorite workouts can overtake our lifestyles, our social media feeds, our day-to-day style choices, and probably too many of our conversations.

Being obsessed with our fitness hobby of choice doesn’t have to be a bad thing—in fact, it can motivate us to spend more time being active and help us develop meaningful communities and relationships with others who are similarly obsessed. But overidentifying with fitness at the expense of other identities, interests, and roles can come with risks for both our mental and physical health.

Why fitness-lovers are prone to over-identifying

Considering how multi-purpose most of our fitness routines are, it makes sense that many of us become invested—or too invested—in them. Not only can fitness be a source of fun and pleasure (and endorphins!), but it can improve our health, boost self-confidence, and reduce anxiety, says Patricia Lally, PhD, a sports psychologist and professor at Lock Haven University.

Embracing this kind of hobby makes us feel good about ourselves for making healthy choices, especially in a culture that lauds physical fitness.

Our workout routines can also become an integral part of our social lives: It’s famously difficult for adults to make new friends outside of work, and running groups, exercise classes, and gym memberships can fill the gap and become the answer to the question, “What do you do for fun?”

The fitness industry is designed to build this sense of social cohesion, since the more we identify with our fitness routine, the more time and money we are likely to spend on it, says Brian Cook, PhD, a researcher who has studied exercise identity and dependence. (Think about how many fitness studios and brands use language like “fit fam” or “tribe” in their marketing.) Sometimes, as in Clor’s case, this social aspect of fitness can create pressure to perform better—leading to even more time spent exercising, and less time developing other interests and identities.

The dangers of making fitness your identity

Our identities are supposed to be multi-dimensional, composed of many roles that come to the surface at the appropriate moments, says Dr. Lally. “But when we over-identify with a single role,” she says, “we look at all those other roles through the lens of the primary role. So when we’re at work, we’re still thinking about running, or we can’t go and watch our child’s activity because we have to get a run in.”

When a fitness obsession begins to take over who we are, we run the risk of losing out on investing in the many other roles that round out our lives, which could lead to weakened relationships, slipping behind at work or school, and missing out on other activities we used to enjoy, says Dr. Lally. And by identifying primarily as a “runner” or a “cyclist” or a “hiker,” we are implicitly asking fitness to fulfill all our needs, something it will never be able to do, says Dr. Cook.

Clor says that after she distanced herself from the identity of “runner,” she felt like she had a “personality transplant,” she says. She noticed herself become less uptight, and more fun, more appreciative, and more interested in the lives of others.

Over-identifying with fitness can also lead to compulsive exercise, says Dr. Lally. This comes with a host of risks, including overtraining and injury, and withdrawal symptoms like feeling irritable, anxious, or restless when we can’t work out.

And as much as we don’t want to imagine not being able to participate in our favorite activity, unfortunately, an injury, illness, or other circumstance could keep us from exercising in the short- or long-term at any time—so tying our self-worth to it is a dangerous game. “What we’re really talking about is our worth,” says Trent Petrie, PhD, a sports psychologist and professor at the University of North Texas. “Is my worth as a person solely defined through my ability to engage in this identity?”

How to make sure your fitness obsession is a healthy one

To be clear, Clor still calls herself a “runner”—after all, “person who runs” doesn’t exactly roll off the tongue. Plus, she thinks it’s important to show her thousands of Instagram followers that imposter syndrome shouldn’t keep them from calling themselves a “runner” if they do indeed run—no matter how far or fast.

But, even though she’s built a life around running, she feels that if she had to stop, she would be fundamentally okay, she says. “That’s always a question I like to ask myself as a mental check in.”

Dr. Cook agrees that the question of whether or not you can stop, or at least take a break from your fitness regimen, is a helpful one in determining if you’re too invested. When you go on vacation, do you feel like you have to find a gym, or do jumping jacks in your hotel room? If you do find yourself trying to fit in workouts at the expense of other priorities—whether that’s rest, family, work, or self care—ask yourself why you feel the need to do so, suggests Dr. Cook.

For Clor, creating a healthier relationship with running meant acknowledging that the sport was not who she was—and taking the time to figure out what defined her at her core. “I started thinking about all the good qualities that I bring to my running,” she says, like her work ethic, and her intelligence. “Once you start valuing yourself for those things, it doesn’t matter what the time on the clock is.”