When relationships first start, you feel like you’re floating on cloud nine and eventually feel stable and grounded. Being in a relationship can change things, from your Friday night plans to your Sunday brunch for two — and even the state of your health. According to an eHarmony study, the five stages of a relationship — butterflies, building, assimilation, honesty, and stability — can make a difference in your overall well-being in the most unexpected ways.

Both the quantity and quality of social relationships affect mental health, health behavior, physical health, and mortality risk. Social relationships, including romantic interactions, can have short- and long-term effects on your health for better or for worse. Whether you’re lovesick or sick of love, it’s known healthy relationships are a vital component of health and wellbeing. Jemima Wade, spokesperson for eHarmony.co.uk, told the Daily Mail: “Here at eHarmony, we're responsible for tens of thousands of relationships and millions of "butterfly" moments every year as a result of getting to know both the heads and hearts of our members.”

One core emotion, love, can be broken down into distinct stages that dictate what happens to couples in relationships physiologically. Love’s impact on health at each stage can shape a person’s behavior and lifestyle. “[E]ach stage may be relived and recaptured as couples grow into a relationship and face different life challenges together,” Papadopolous told the Daily Mail.

With the assistance of Papadopolous, an eHarmony research team sought to identify how the five stages of love affect couples’ overall wellbeing. The participants were asked to complete a psychological test to determine their true feelings throughout the different stages of a relationship. They were asked questions about their behavior and lifestyle in order to accurately reveal the influence love has on a person’s health at each stage.

The findings were grouped into the before-mentioned five stages: butterflies, building, assimilation, honesty, and stability. The stages can be relived as the couple continues to grow in the relationship and begins to face life challenges at different times. They capture how couples evolve from the uneasy "butterflies" feeling to feeling stable and content in a relationship.

Stage One: Butterflies

“Butterflies is a great way to describe it — the time when you can't stop having sex,” Papadopolous said about stage one. This “butterflies in your stomach” feeling is found to be marked by intense infatuation and sexual attraction. During this time frame, 30 percent out of the 33 million people currently in stage one in England reported weight loss, while 39 percent reported a lack of productivity. Both men and women also created more of the sex hormones testosterone and estrogen.

Stage Two: Building

This is when the honeymoon stage dissipates and the couple begins to build their relationship. This stage is marked by feelings of “happy anxiety,” where people’s attention span is bad and they’re unable to focus. The body begins to act as if it were on drugs, as the monoamine neurotransmitters speed up heart rate, trigger rushes of pleasure, and mimic the effects of Class A drugs. Papadopoulos said: “It can also be difficult sleeping. You're literally kept awake thinking about the other person. And there is a sense of happy anxiety, where you feel drunk on love.”

Stage Three: Assimilation

This stage forces a couple to question whether the relationship is “right.” Couples begin to ponder about the future of their relationship and start to form boundaries in the relationship that can lead to a rise in stress levels. “The third stage is when it becomes more serious. You start thinking, 'This is more serious than I thought' and 'I know you, but where are you at in your life? Do we want the same things? and Can we figure this out?'"

Stage Four: Honesty

The assimilation stage combined with stage four is where people begin to open up and show their “real” selves. This induces the first real rise in stress levels and anxiety. Papadopolous acknowledged this is the stage where couples put on their “best faces” through social media and pictures to portray everything is fine. Assimilation and honesty shows an increase in stress levels.

Stage Five: Stability

The last stage in a relationship is stability, which increases levels of trust and intimacy. In this stage, the powerful hormone vasopressin, released by men and women during an orgasm, is known to strengthen feelings of attachment. In addition, oxytocin is released as well, deepening bonds between couples, according to a 2011 study published in the Indian Journal of Endocrinology and Metabolism. “This is where we see a real level of contentness,” Papadopolous said.

The quantity and quality of relationships matter when it comes to health. They can have a significant toll on your health in the most unusual ways. It’s important to learn how to identify the symptoms of each relationship stage to have better control of your health.