The words you use say a lot about you. But a new paper published in the Proceedings of the National Academy of Sciences suggests this goes a lot deeper—like, gene expression deep—than we think. Researchers found that subtle changes in our language may be a better indicator of how physiologically stressed we are than our own assessment of our feelings.

Stress, especially chronic stress, can wreak havoc on the body. In a piece about the study findings for Nature, Jo Marchant writes about how stressful situations like living in poverty, feeling isolated or experiencing trauma can lead to chronic health issues like dementia and heart disease. Researchers have found that people living in these circumstances “also undergo broad changes in gene expression in the cells of their immune system,” Marchant writes.

But it turns out our genes and our word choices tell a different, and more accurate, story about our physical stress levels than how stressed we think we are. That discrepancy nagged Steve Cole, a co-author on the paper and genomicist at University of California, Los Angeles, who decided to study it.

Cole and fellow researchers from institutions including the University of Arizona, Tucson, had 143 volunteers wear audio recorders for two days. The recorders turned on every few minutes, and the audio footage was analyzed by Matthias Mehl, a psychologist at the University of Arizona, Tucson, who studies how stress affects our language, specifically word choice.

To be clear, the researchers were looking at physiological stress, which is different from how we feel about our stress on a day-to-day basis. But our physical stress can take a toll on our body and mind, as this piece by Markham Heid on Thrive Global explores. 

Mehl was looking for what psychologists call ‘function’ words like pronouns and adjectives, Marchant writes. These words don’t necessarily carry meaning on their own, but they help clarify and contextualize our sentences. Here’s an example: in the sentence “do you want this ice cream cone?” the word ‘do’ is the function word.

On the other hand, nouns and verbs have more meaning, and we’re more conscious about choosing ours. For the purposes of this experiment, the function words were more important as they may reveal how we’re unconsciously dealing with issues in our lives. For instance, the researchers found that “people’s use of function words changes when they face a personal crisis or following terrorist attacks,” Marchant writes.

They found that using function words was a better predictor of biological stress compared to self-reports about well-being. They measured biological stress by looking for the expression of genes in subjects’ white blood cells known to be “influenced by adversity,” Marchant writes.

People with “more stressed-out gene-expression signatures tended to talk less overall,” Marchant writes. They also used more adverbs like ‘really’ or ‘incredibly,’ which Mehl said may be “emotional intensifiers” that indicate a “higher state of arousal.” The stressed-out gene folks were also less likely to use third-person plural pronouns like ‘their’, which Mehl theorizes may be because people focus inward rather than outward when they feel threatened.

While more research is needed to understand this link, these findings could have interesting implications in the real world—doctors could identify stress-related health problems by focusing on patient’s word choices, rather than self-reports, and perhaps get a more accurate understanding of a patient’s overall health and well-being.

Read more on Nature.