On Valentine’s Day our thoughts turn to love. I’m not a relationship expert, so I can’t help you find your soul mate—sorry. When it comes to running, however, I’ve been around long enough to opine on how you can develop a love that will lead to both peak experiences and a lifetime of continued passion.

In my experience, runners who fail to find lasting love tend to fall into two camps. The first are those who never get close enough to build a love. They go on a few dates and find running fascinating but intimidating. They are not willing to take the time and effort to get to know and appreciate it. They like the flashy weekends and being seen together, but not the day to day. They endure the tedium for a while to get the rewards, but they inevitably drift apart. They never form an enduring passion.

On the other side are those who develop an obsessive passion. While they are together, the relationship consumes and smothers. They spend all their time and thought on it and lose all their other friends and interests. They must be together, and everything must always be perfect. They think that they are taking it to its peak, but the obsessiveness is overwhelming and unsustainable both physically and emotionally. Inevitably, it flames out quickly, or it becomes an on-again, off-again torrid affair that ends in hurt and bitterness.

A year ago I interviewed over 50 runners who have been competitors from youth to masters, succeeding on the track, road and trail for forty, fifty or more years. In my book, Run Strong, Stay Hungry, I detailed 9 keys I found in common among these runners that have helped them stay in the race. A year later, as the stories sink in and I try to understand and apply the lessons, I’m increasingly convinced that all the keys stem from developing a harmonious passion.

“Passion can fuel motivation, enhance well-being, and provide meaning in everyday life,” wrote psychologist Robert Vallerand in a 2003 journal article, “Les Passions de l’Âme.” But passion is a two-edged sword. Those with a harmonious passion, Vallerand wrote, “are not compelled to do the activity but rather they freely choose to do so. With this type of passion, the activity occupies a significant but not over­powering space in the person’s identity and is in harmony with other aspects of the person’s life.”

In contrast, those with an obsessive passion feel they must run because running is so integral to their identity that they have to live up to expectations, real or perceived. “I get to run today” turns into “I have to run today”—and I have to run at a certain level. “The passion must run its course as it controls the person,” wrote Vallerand. Their running becomes an overwhelming love where they ditch their jobs and relationships so that they can run more—or wish they could. That kind of imbalance leads to either resenting other life demands or resenting the sport, or a caustic combination of both in a guilty cycle.

Developing a harmonious passion requires altering some common perspectives on running. Perhaps the greatest is revealed in many post-championship interviews when the reporter asks how much sacrifice and dedication it took to get here and what they are looking forward to indulging in now that it is over. The assumption is that we all really want to be couch potatoes and we only discipline ourselves to run in order to achieve an external goal.

Most champions, however—at least those who show up on the podium year after year—are doing what they want to be doing. Sure, the goal motivates them. It helps them to get out of bed on cold winter mornings and to push harder on a hill workout. But once out the door, they enjoy the beauty of a sunrise while flying comfortably along a snowy country road. They learn to love the effort, even the pain, of those hard workouts. They especially enjoy the feeling of getting better. These daily affirmations of their ability and progress make them who they are; they aren’t begrudged sacrifices en-route to a goal. Results are nice, but they have meaning only in the context of mastery.

“Progressing, even in the smallest way, is so rewarding,” Deena Kastor told me. “That has really been the reward of running. It hasn’t really been the medals or accolades or the records. It has been those moments of clearly seeing you’ve created a stronger version of yourself. Running is rewarding in itself.”

Develop a harmonious passion also requires giving up perfection. Like in any relationship, a healthy running life is based on honesty. Honesty about where we’re starting, how much we are able to give to the relationship at this time, and what goals are possible. That doesn’t mean settling. Like the Valentine’s Day illusion of the perfect romantic life in paradise with the movie star, conventional wisdom paints an athletic picture of unfettered glory if you go all in and can align everything perfectly. The illusion tells us that anything less than perfect isn’t worth doing. Holding to such an illusion causes us to disdain the progress we can make today and despair at the huge chasm between our dreams and our reality.

Lifetime competitors demonstrate honesty with a combination of humility and hunger. They see where they are with clear eyes and accept that reality, while maintaining a hunger and a hope for improvement and mastery. That humble honesty allows them to adapt to changing life situations and abilities and to keep working and enjoying each day’s progress. And, ironically, in the process of getting better each day, they often rise higher than those who “won’t settle for less than the best.”

A harmonious passion also sets runners up to master another trait common to lifetime competitors: training by feel. If you’re enjoying each run, each type of workout, and the full process of becoming the best runner you can be, then you can be attuned to your body’s needs. You can go long when you need to go long (happily indulging in your passion for hours), go fast when you need sharpening (enjoying the wind in your hair and the burn in your lungs), and rest when you need to rest (confident and comfortable in the knowledge that you are maximizing what your body is able to handle and enjoying the feeling of recovery and growing strength). Runners with harmonious passion don’t say I “have” to do this workout today, because the schedule calls for it, or I “should” go long, because I’m supposed to get in x-number of miles each week. They get up each morning wondering how much and how fast they can run today to improve; then, assessing themselves honestly, they accept and enjoy whatever that run is.

The classic Bill Murray movie Groundhog Day asks the question, “What if there was no tomorrow?” Through trial and error Phil, the lead character, learns that joy comes not by trying to maintain his status, not through indulging himself, not by trying to line up everything perfectly toward an objective—but by becoming the best he can be today in the circumstances he finds himself. In the end, he is able to say, “No matter what happens tomorrow, or the rest of my life, I’m happy now…”

If you weren’t guaranteed of tomorrow would you still run today? Would you try to run your best? If you can say yes, you’re on your way to a lifetime of enjoyment and success. Do you want to fall in love with running for life? Honestly and humbly make peace with your abilities and life circumstances, work hopefully to improve, and enjoy each step of progress. A harmonious passion will lead you to your best times and to being your best throughout time.