Category Archives: cortisol

The other day, I came across a wonderful initiative that gives children something far more valuable than a toy: books and the opportunity to discover the power of words from an early age.

Through Dolly Parton’s Imagination Library, registered children receive a free, age-appropriate book every month from birth until their fifth birthday. It is a simple but powerful idea—helping children develop a love of reading while giving them access to a richer world of language, imagination, and ideas.

It also made me reflect on something we often underestimate: The words we hear, read, speak and repeat influence how we think, how we feel, how we relate to others, and, increasingly, research suggests, how our bodies respond to stress and emotion.

From the first stories we hear as children to the language that surrounds us as adults, the words we live with help shape our lives.

When leaders normalise belittling, insulting, humiliating or threatening language, they give their followers permission to do the same. We can see the consequences particularly clearly on social media, where emotionally charged discussions can deteriorate rapidly into personal attacks, contempt and hostility. A disagreement about an idea becomes an attack on the person.

This matters because language is not psychologically neutral. The words we repeatedly encounter and use influence attention, interpretation, and emotional responses. 

Stress, anger, and hostility can activate physiological systems involved in the body’s stress response, while positive emotions, social connection, and a sense of meaning can support psychological resilience.

Repetition of negative language

Repeated exposure to words and messages associated with anger, fear and hostility can reinforce particular patterns of attention and interpretation. Over time, this may contribute to a more threatening or pessimistic perception of the world.

There is an important distinction, however: words do not automatically cause disease, and the science is more nuanced than the popular claim that simply hearing a negative word raises cortisol or damages the body. What matters is the broader psychological response—particularly when threatening or hostile language becomes persistent, personally meaningful and part of a chronic environment of stress.

A landmark 2015 study published in Psychological Science analysed millions of Twitter messages from 1,347 U.S. counties. Researchers found that county-level use of language expressing anger, anxiety, negative relationships and disengagement was associated with higher rates of atherosclerotic heart-disease mortality, while positive-emotion and engagement language showed protective associations. The researchers reported that their language-based model predicted cardiovascular mortality better than a model combining ten conventional demographic, socioeconomic and health variables.

These findings were striking—but they should not be interpreted as proof that negative words themselves cause heart disease. The study was observational and conducted at the community level, and subsequent methodological criticism has questioned how robust and generalisable the associations are. What the research does support is a fascinating possibility: the emotional language circulating within a community may act as a window into its collective psychological climate.

Other research provides a more direct connection between stress and language. Experimental studies have found that people experiencing greater physiological stress—including higher cortisol and heart-rate responses—tend to produce less cognitively complex speech. More recent research is also exploring whether characteristics of speech can themselves be used as indicators of stress.

The potential of positive language

The opposite is also worth cultivating. Kindness, gratitude, appreciation, compassion and encouragement can change the quality of our interactions and strengthen social bonds. And strong social relationships are among the most important resources we have for psychological resilience and wellbeing.

Research on self-affirmation offers an interesting insight into how constructive language can work. In laboratory studies, reflecting on personally important values activated brain regions involved in self-related processing and positive valuation. In one study, these neural responses were subsequently associated with changes in sedentary behaviour.

This does not mean that repeating positive words is a magical cure. Nor does it mean that we should suppress difficult emotions or pretend that everything is wonderful. Healthy language can acknowledge suffering while still leaving room for possibility:

I am struggling—but I can seek help.

I disagree with you—but I can still respect you.

This is difficult—but it is not necessarily hopeless.

Such language does something important: it creates psychological space. Instead of narrowing our attention around threat, blame and fear, it can help us recognise choices, relationships and possibilities.

Words, mantras and prayer

This may help explain why human beings across cultures have used mantras, prayers, chants and contemplative phrases for thousands of years.

The benefit may not lie simply in the meaning of the words. Repetition slows attention, reduces distraction and can be accompanied by rhythmic breathing. Studies of contemplative practices have found associations with changes in autonomic regulation, including heart-rate variability, although the evidence varies considerably according to the practice and study design.

Research into music and prayer has also suggested that slow rhythmic structures can influence cardiovascular rhythms. Work examining musical tempo and autonomic responses has highlighted the role of slow breathing and rhythm in producing calming physiological effects.

This offers a more scientifically cautious way of understanding the experience many people report when listening to or singing something such as Ave Maria, whether in the settings of Schubert, Gounod or other classical arrangements. The combination of familiar words, melody, repetition, breath, memory and spiritual meaning can create a profound sense of calm and emotional safety.

For a person of faith, there is an additional dimension that science cannot easily measure: prayer can provide a sense of relationship, trust, meaning and transcendence. These subjective experiences may themselves be important sources of psychological resilience.

Read good words

There is another simple way of nourishing our inner vocabulary: read books.

In an age dominated by short posts, headlines, notifications and rapidly changing fragments of information, sustained reading offers something very different. A book asks you to remain with an idea, follow an argument, inhabit another person’s experience and encounter words in context.

Reading also exercises language itself. It exposes you to a richer vocabulary, more complex sentence structures, metaphors, stories and unfamiliar perspectives. This matters not only intellectually but potentially for healthy ageing.

A 14-year longitudinal study found that older adults who reported reading at least weekly were less likely to experience cognitive decline over six, ten and fourteen years than those who read less frequently. The association remained after adjustment for relevant covariates.

A separate 2024 study of older Japanese adults found an association between childhood availability of books and cognitive function later in life, particularly among participants with lower educational attainment. The researchers also identified an association involving the volume of the left superior temporal cortex, an area important for language and related cognitive functions. Because this was an observational study, it cannot establish that books themselves caused the difference—but it adds to the growing evidence that a life rich in reading and language may be beneficial for cognitive ageing.

Perhaps, then, we should think of vocabulary as a kind of mental landscape.

If your daily diet consists largely of words such as threat, enemy, stupid, hate, crisis, failure and fear, you are repeatedly exposing your attention to a narrow emotional vocabulary.

But if you also make room for words such as curiosity, courage, gratitude, wonder, forgiveness, possibility, beauty, compassion, stillness, love and hope, you give the mind more possibilities with which to interpret experience.

The goal is not to eliminate negative words. Anger can alert to injustice. Fear can protect from danger. Grief gives expression to loss. Difficult words have their rightful place.

The deeper question is:

What kind of language do you want to live with within?

And perhaps an equally important for everyone is:

What kind of emotional climate are your words creating for the people around you?

Words are small things. But repeated millions of times, they can become attitudes, attitudes can become behaviours, and behaviours can become culture.

Choose them carefully.

Reino Gevers – Host of the LivingToBe podcast

P.S: If you enjoyed this article, you might be interested in reading one of my four books, available where all good books are sold.

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