Written by Dr. Tim Loving for Science of Relationships (scienceofrelationships.com)
Several years ago, I read a journal article in which the researchers reported that individuals who had recently fallen in love (i.e., they were ‘madly, deeply in love’, or experiencing what researchers refer to as passionate love) had higher levels of cortisol than did individuals in long-term relationships or those in no relationship at all.1 If you’re unfamiliar with cortisol, it is one of the human body’s primary stress hormones and affects a host of bodily processes (e.g., metabolism and immune function). Importantly, high levels of cortisol can eventually weaken the immune system and undermine physical health. Admittedly, this finding baffled me. If chronically high levels of cortisol can be bad for health, then how does that explain the overwhelmingly positive impression people have of being passionately in love? I’ve yet to find a Valentine’s Day card that reads, “I love you so much that you make me susceptible to pneumonia.”
Importantly, researchers in the original study collected a blood sample (to measure cortisol) from study participants after an intensive interview that was designed to confirm participants were indeed ‘madly, deeply in love’ (and not just crazy). This intrigued me. Falling in love with another person is a major life transition – it may be positive, but it’s a transition nonetheless, and transitions necessitate change. Think about it. When you fall for another person, your self-concept changes, your daily routines change, your relationships with friends change, and so on. All change requires adaptation, and adapting to any new environment is stressful to some degree. Perhaps just reminding people of falling in love, and the associated changes, was enough to temporarily raise their cortisol levels.
My lab subsequently set out to further investigate this effect.2 We reasoned that falling in love would affect relationship-focused people (i.e., they think a lot about relationships) more than less relationship focused individuals — because all the transitions that come with falling in love should be more salient, or obvious, to more relationship-focused people. To test this, we asked 29 women, all of whom reported experiencing high levels of passion, to come into our lab and engage in one of two ‘guided imagery’ tasks. Specifically, half of the women relived the moment they realized they were in love with their current partners. They closed their eyes and recreated that moment as vividly as possible, and then talked and wrote about the experience in as much detail as possible. The other half of the women in the control group relived the moment they realized they wanted to be friends with someone who was of the same age and sex as their dating partners. We collected saliva samples before and after the guided imagery tasks so that we could determine whether the mental reflection changed cortisol levels. We also asked all of the women to indicate how much they tended to think about their relationships in general.
Cortisol levels increased when women thought about falling in love, but how much they increased depended on how relationship-focused they were: Cortisol levels dropped shortly after the guided imagery if they were ‘low’ relationship thinkers, but cortisol levels continued to rise for up to 30 minutes if they were ‘high’ relationship thinkers. Women in the ‘friendship’ guided imagery session showed no increases in cortisol. In other words, just asking a woman to think about falling in love is enough to cause an increase in cortisol, especially if she is more apt to think about relationships already.
Does this mean falling in love is stressful? It would appear so, especially for some more than others. But it doesn’t necessarily mean falling in love is ‘bad stress’. Not all stress undermines health, and there are also other possible reasons for increases in cortisol. For example, increases in cortisol may simply reflect arousal more generally. There’s a reason we say somebody ‘turns us on’, and arousal, attraction, and passion tend to go hand in hand. My students and I, and others, are working to figure all this out. In the meantime, it’s probably safe to assume the passion in your relationship (whether it’s there today or tomorrow) won’t make you sick.
1Marazziti, D., & Canale, D. (2004). Hormonal changes when falling in love. Psychoneuroendocrinology 29, 931—936.
2Loving, T. J., Crockett, E. E., & Paxson, A. A. (2009). Passionate love and relationship thinkers: Experimental evidence for acute cortisol elevations in women. Psychoneuroendocrinology, 34, 939-946.
Tim Loving, faculty member in Human Development and Family Sciences, is a founding member of Science of Relationships (scienceofrelationships.com). Science of Relationships is, really just that—active and productive researchers in the field of interpersonal relationships writing and discussing their field of expertise.