29 Runners Tried Positive Self-Talk and Their Cortisol Dropped

In a study of 29 well-trained male runners published in Psychophysiology in 2022, the group cued to use positive, motivational self-talk during a one-hour run finished with significantly lower cortisol levels and a slower breathing rate than the group cued to use negative self-talk.¹ Same runners. Same effort. Different sentences in their heads.

That last detail is what makes the finding interesting. The bodies were doing the same physical work, but the words running on a loop inside their minds appeared to nudge their stress hormones in opposite directions. The researchers, led by Fabien Basset at Memorial University of Newfoundland, framed it as evidence that self-talk can shape the body’s autonomic response, not just the runner’s mood.

What the runners actually did

The study put 29 trained male runners through a 60-minute run at an intensity matched across both conditions, what the authors call iso-metabolic exercise. Each runner did the run twice, on separate days, in a counterbalanced order. Once they were cued to repeat motivational, encouraging statements in their head. Once they were cued to repeat critical, defeating ones. The researchers measured perceived exertion, breathing rate, heart rate, and salivary cortisol before and after.¹

Cortisol is the body’s main stress hormone. It rises when the brain reads a situation as taxing, whether the threat is a deadline, a difficult conversation, or a hard run. The Basset paper reports that the positive self-talk condition produced a smaller cortisol response and a lower post-exercise breathing frequency. Heart rate during exercise looked similar across conditions, which fits the iso-metabolic design. The signal showed up in hormones and breathing, not in raw cardiovascular output.¹

The runners’ perceived exertion, how hard the run felt, also tracked the self-talk. People felt the run as less brutal when their inner voice was on their side. That tracks earlier work on endurance: how a long effort feels is shaped not just by lactate and heart rate but by attention, expectation, and the words a person uses to describe what is happening to them.³

How could a sentence change a hormone?

The proposed mechanism is not mystical. The brain is the organ that decides how stressed the body should be. The hypothalamus, sitting just above the brainstem, talks to the pituitary, which talks to the adrenal glands, which release cortisol. That chain is called the HPA axis, and it is exquisitely sensitive to context. The same physical task can light it up or leave it quiet depending on what the brain decides the task means.

Self-talk is one way the brain tells itself what something means. “I cannot do this, my legs are gone” is a meaning. “I am strong, this is just the middle” is a different meaning. Neuroscience work on emotion regulation suggests that the simple act of describing a stressor in slightly more distanced language (“you can do this” rather than “I cannot do this”) engages prefrontal regions that cool down the amygdala, the brain’s alarm hub.² A quieter amygdala tends to mean a less aggressive HPA-axis response, which means less cortisol.

None of that is unique to running. The same architecture is at work when someone is about to give a talk, sit an exam, or have a hard conversation with a partner. The Basset study just happened to catch it on a treadmill, where physiology is easy to measure.¹

It is not just one study

One trial of 29 men is not enough to redesign your inner life around. The reason this finding matters is that it lines up with a much larger body of sport-psychology work.

A 2015 review in Sports Medicine by Alister McCormick and colleagues at the University of Kent looked across the psychological determinants of whole-body endurance performance. Self-talk consistently came up as one of the better-supported tools, alongside imagery and goal setting, for improving how long people can sustain a hard effort and how unpleasant they perceive that effort to be.³ The mechanism the authors landed on was perceptual: self-talk seems to lower the felt cost of work, which delays the moment a person decides to slow down.

A 2014 paper from Ethan Kross and colleagues in the Journal of Personality and Social Psychology took the same idea into anxiety. Across seven experiments, people who silently referred to themselves in the second or third person (“you can handle this”, or by name) before a stressful task showed less self-reported anxiety, performed better, and ruminated less afterward than people who used “I”. The shift in pronoun was small. The shift in stress response was not.²

Even militaries have noticed. A 2018 review in Military Medicine on sport psychology for soldier-athletes describes self-talk and similar mental-skills techniques as practical tools for managing acute stress in physically demanding contexts.⁴ The military is not a sentimental customer. If the technique survives that scrutiny, the underlying signal is probably real.

Does the content of the self-talk matter, or just the tone?

This is where the picture gets more textured. A 2021 study in Consciousness and Cognition by Johanne Nedergaard and colleagues asked athletes about the valence (positive or negative), the form (first or second person, abbreviated or full sentences), and the content of their self-talk. They found that all three predicted both the type of sport someone played and the level at which they played it.⁵

The honest summary: positive self-talk is not a single tool. A motivational phrase (“come on, push”) and an instructional one (“relax your shoulders, shorten your stride”) are different beasts. Both can help. The first lowers anxiety and lifts effort. The second redirects attention to a useful technical cue. The Basset study leaned on the motivational kind, which is the kind most people instinctively reach for under pressure.¹

Tone matters too. There is a difference between gentle encouragement and forced cheerleading. Sport psychologists who train athletes in self-talk usually warn against phrases that are obviously untrue (“this is easy”), because the brain is not stupid and registers the lie. Phrases that are plausible and concrete (“you have done this before, keep your cadence”) tend to land better than generic affirmations.

What about negative self-talk? Is it always bad?

The flip side of the Basset finding deserves an honest look. Negative self-talk did not just fail to help; it produced higher cortisol and faster breathing.¹ That is consistent with how psychologists have long understood rumination: chewing on your own failures is itself a stressor.

That said, not every critical inner voice is harmful. Some self-criticism is diagnostic (“my form is sloppy, fix it”) rather than abusive (“you are pathetic”). The first kind seems to feed back into better performance. The second kind tends to spike physiology without any matching change in behavior. Researchers sometimes call the useful kind instructional self-talk and the harmful kind defeatist self-talk, and the gap between them is mostly a gap in tone and target. One attacks the action. The other attacks the person.⁵

A practical way to use this

Reading the source post that prompted this article (“Sometimes the kindest thing you can do for your body starts with the words inside your own head”), it is tempting to leave it there. Pretty sentence, file under inspiration. The research suggests something more usable.

First, notice the phrase you actually use under pressure. Most people have a default. It might be “I cannot believe I am doing this again”, or “this is going to be a disaster”, or a single contemptuous word about themselves. The Basset study and the Kross experiments share an assumption: you cannot edit a phrase you have not heard.^1,2

Second, swap in something concrete and second-person. Not a slogan. A sentence that addresses you by name or as “you”, and that names a small specific thing to do. “Sara, breathe out longer than you breathe in.” “You have run hills harder than this. Settle.” The Kross work suggests the second-person framing alone reduces anxiety, partly because it creates a tiny psychological distance between the worried self and the planning self.²

Third, expect the effect to be modest and stack-able. One study of 29 male runners cannot promise that the same shift will work the same way for a postpartum mother trying to walk through a panic attack at the supermarket, or for a teenager sitting an exam. Sex, training status, baseline anxiety, and culture all probably modulate this. But the direction of effect is consistent enough across studies that it is reasonable to treat self-talk as a real, low-cost lever, not a placebo.^3,4

What the evidence does not say

The Basset study had 29 participants, all male, all well-trained runners.¹ That is a normal sample size for an exercise-physiology trial and a real limitation at the same time. We do not have strong direct evidence that the cortisol effect generalizes to women, untrained people, older adults, or people with diagnosed anxiety disorders. The wider sport-psychology literature is broader, but it leans heavily on competitive athletes too.³

Self-talk is also not a substitute for clinical care. If anxiety, panic, or chronic stress are interfering with daily life, the right move is a conversation with a clinician, not a phrase. The research here is about tilting the dial under everyday pressure. It is not a treatment for a disorder.

Common questions about positive self-talk

Does positive self-talk really lower cortisol?

In the 2022 Basset study of 29 trained male runners, yes. Compared with negative self-talk during the same one-hour run, motivational self-talk produced a smaller post-exercise cortisol response and slower breathing.¹ Whether the effect size is the same in women, untrained people, or non-exercise contexts is not yet well established.

Is talking to yourself in the third person weird?

It feels weird. The Kross experiments suggest it is also useful. Saying “you can handle this” or using your own name appears to create a small amount of psychological distance and to reduce anxiety more reliably than first-person “I” framing.²

How long does it take to change a self-talk habit?

The studies do not give a clean answer. Acute effects can show up in a single session, as the Basset trial demonstrates. A durable change in the default inner voice tends to take weeks of practice, often supported by a coach or therapist.

Can you overdo positive self-talk?

Yes, in the sense that obviously false phrases (“this is easy when it is not”) tend to backfire. Plausible, specific, and slightly compassionate phrases land better than generic affirmations.

Is there a difference between thinking the words and saying them out loud?

The Basset runners repeated cued statements internally, not aloud.¹ Most of the broader literature treats internal and quietly spoken self-talk as similar in effect, though the research base is mixed.

Where this leaves you

The most honest reading of the Basset paper is that it is one piece of evidence for an idea that already had decent support: the brain decides how stressed the body should be, and self-talk is one of the tools the brain uses to make that decision. Twenty-nine runners is not a population. A one-hour treadmill run is not a panic attack at three in the morning. Still, the direction is consistent across the wider literature, and the cost of trying it is essentially zero.^1,3

If there is a takeaway worth keeping, it is small and concrete. The next time something hard is happening to your body, listen to the sentence inside your head. If it is cruel, you do not have to fight it. Just write a better one and try that instead, by name, in the second person, with a small specific instruction. The cortisol may or may not move. The next minute will probably feel different.

Sources

1. Basset FA, Kelly LP, Hohl R, Kaushal N. Type of self-talk matters: Its effects on perceived exertion, cardiorespiratory, and cortisol responses during an iso-metabolic endurance exercise. Psychophysiology, 2022. PubMed: 34837395
2. Kross E, Bruehlman-Senecal E, Park J, Burson A, Dougherty A, Shablack H, Bremner R, Moser J, Ayduk O. Self-talk as a regulatory mechanism: how you do it matters. Journal of Personality and Social Psychology, 2014. PubMed: 24467424
3. McCormick A, Meijen C, Marcora S. Psychological Determinants of Whole-Body Endurance Performance. Sports Medicine, 2015. PubMed: 25771784
4. Meyer VM. Sport Psychology for the Soldier Athlete: A Paradigm Shift. Military Medicine, 2018. PubMed: 29420813
5. Nedergaard J, Christensen MS, Wallentin M. Valence, form, and content of self-talk predict sport type and level of performance. Consciousness and Cognition, 2021. PubMed: 33618165