When we experience stress, the body responds rapidly.
Heart rate rises. Breathing may become faster and more pronounced. The nervous system shifts towards a state of increased alertness, preparing us to respond to a perceived threat.
This response is useful when we genuinely need to act. The problem is that modern life can trigger the same physiological response during a difficult conversation, a presentation, an email, a traffic jam or an unexpected demand at work.
So, can we use our breathing to influence this stress response?
A new 2026 randomised controlled trial provides some interesting evidence that we can.
Researchers compared box breathing, prolonged exhalation and normal breathing to see whether brief breathing practices could reduce the body’s response to an acute psychological stressor.
The results suggest that they can.
Frequently asked questions
Can breathwork reduce stress?
Research suggests that some forms of controlled breathing can reduce subjective and physiological markers of acute stress. This 2026 randomised controlled trial found that both box breathing and prolonged exhalation reduced several markers of acute stress compared with normal breathing.
Does box breathing lower cortisol?
Not according to this particular study. No significant differences in cortisol were found between the breathing and normal breathing groups. More research is needed to understand how different breathing practices influence cortisol over different time periods.
Is prolonged exhalation good for anxiety?
This study found that participants using prolonged exhalation did not experience the increase in state anxiety seen in the normal breathing group following the stress test. However, breathwork should not be considered a replacement for appropriate professional support for persistent or severe anxiety.
How long should I practise breathwork for stress?
The optimal duration depends on the individual and the breathing technique. Importantly, this study found effects following a relatively brief intervention, with five minutes of breathing before the stress test and one further minute during it.
Is breathwork the same as deep breathing?
No. Breathwork encompasses many different techniques. Some involve slowing the breath, some emphasise a longer exhalation, some use breath holds and others deliberately change breathing volume. For stress regulation, more breathing is not necessarily better. The aim is usually to find a breathing pattern that is comfortable, controlled and appropriate for the individual.
The study at a glance
The study, published in Comprehensive Psychoneuroendocrinology, involved 66 healthy adults aged 18 to 39.
Participants were randomly allocated to one of three groups:
- Box breathing
- Prolonged exhalation
- Normal breathing
They then completed a modified virtual Trier Social Stress Test, a well-established laboratory method for creating a controlled psychological stress response.
The researchers measured several indicators of stress, including:
- Heart rate
- Subjective anxiety
- Heart rate variability (HRV)
- Salivary alpha-amylase
- Salivary secretory immunoglobulin A (SIgA)
- Cortisol
- Cognitive performance
The participants in the two breathwork groups completed their breathing practice for five minutes before the stress test and for one further minute during the test.
The findings were particularly interesting.
What did the researchers find?
Both breathing techniques reduced several markers of acute stress reactivity compared with normal breathing.
1. Heart rate was lower
The normal breathing group experienced the expected increase in heart rate following the stress test.
In contrast, both the box breathing and prolonged exhalation groups experienced a decrease in heart rate from their pre-stress measurement.
This suggests that these brief breathing practices may help reduce the cardiovascular activation associated with acute psychological stress.
2. Anxiety did not increase in the breathwork groups
The normal breathing group experienced a significant increase in state anxiety following the stress test.
There was no significant increase in anxiety in either the box breathing or prolonged exhalation groups.
This is an important finding because it suggests that the breathing practices may have helped participants remain more physiologically and psychologically steady when faced with a stressful situation.
3. Salivary alpha-amylase was reduced
The researchers also measured salivary alpha-amylase, an enzyme commonly used as a marker associated with sympathetic nervous system activity and acute stress.
Both breathing groups showed a smaller stress-related increase compared with the normal breathing group.
This provides another indication that the breathing practices influenced the body’s physiological stress response, rather than simply making participants feel subjectively calmer.
What is particularly interesting about this study?
One of the strengths of this research is that the researchers did not simply ask participants whether they felt less stressed.
They looked at several physiological measures as well.
This matters because stress is not just a psychological experience. It is a whole-body response involving the brain, autonomic nervous system, cardiovascular system and endocrine system.
The study therefore adds to the growing body of evidence suggesting that breathing can influence the physiological response to stress.
And it did so using techniques that are simple, inexpensive and practical.
What exactly were the breathing techniques?
The box breathing protocol was:
4 seconds inhale → 4 seconds hold → 4 seconds exhale → 4 seconds hold
This was repeated continuously.
The prolonged exhalation protocol was slightly different.
Participants took:
3 seconds to inhale through the nose → 6 seconds to exhale slowly through pursed lips
They performed one of these prolonged-exhalation breaths every 30 seconds, returning to normal breathing between breaths.
This is an important distinction.
The study was not testing continuous 3:6 breathing. It was testing intermittent prolonged exhalations, sometimes described as a “reset breath”.
Why might slowing and controlling the breath help?
One of the reasons breathwork is so interesting is that breathing sits at the intersection of conscious control and the autonomic nervous system.
We do not normally have to think about breathing. It happens automatically.
But unlike many other autonomic processes, we can deliberately change our breathing pattern.
When we deliberately slow and regulate the breath, particularly when we avoid over-breathing, we can influence several physiological processes involved in the stress response.
A slower, more controlled breathing pattern can help create a shift away from the rapid, reactive breathing that commonly accompanies stress.
The extended exhalation used in this study may be particularly useful because it encourages a slower respiratory rhythm and gives the body an opportunity to move towards a less activated state.
This does not mean that every breathwork technique will have the same effect.
Breathwork is not one single intervention.
The physiological effects can vary depending on breathing rate, depth, pauses, respiratory volume, nasal or mouth breathing, the length of the practice and the individual’s starting state.
That is why research comparing specific techniques is so valuable.
Did breathwork reduce cortisol?
Interestingly, no significant difference in cortisol was found between the groups.
This is worth highlighting because cortisol is often described as “the stress hormone”, and breathwork is sometimes promoted as a way to immediately lower cortisol.
This study does not support that claim.
Cortisol did not show a significant stress response in this particular experiment, and the researchers suggest that the modified virtual stress test may not have been sufficiently intense or prolonged to produce the expected cortisol response.
So, based on this study, it would be more accurate to say:
Brief breathwork reduced several markers of acute stress, but this study did not demonstrate an immediate reduction in cortisol.
That is a much more useful and scientifically responsible conclusion.
What about HRV?
The researchers also measured heart rate variability, or HRV.
Despite the changes seen in heart rate and other stress markers, there were no significant changes in HRV between the groups.
This is another useful reminder that different measures of nervous system function do not necessarily change at the same time.
It is tempting to assume that if a breathing exercise “activates the parasympathetic nervous system”, HRV must immediately increase.
The reality is more nuanced.
HRV is influenced by many factors, including breathing rate, posture, fitness, sleep, stress, age, measurement conditions and individual physiology.
The researchers therefore concluded that these very brief breathing practices may have reduced acute stress responses without producing measurable changes in HRV during this experiment.
Did breathwork improve cognitive performance?
The study also tested cognitive performance using a Stroop colour-word task and mental arithmetic.
There were no significant differences in cognitive performance between the three groups.
So this research does not demonstrate that five minutes of box breathing or prolonged exhalation makes you think faster or perform better on cognitive tasks during acute stress.
That does not mean breathwork cannot influence attention or cognitive function.
It simply means that this particular study did not find evidence for that effect.
Other research has investigated the relationship between paced breathing, attention and cognitive performance, but those findings should not be attributed to this study.
What does this mean in everyday life?
Perhaps the most useful message from this research is that you do not necessarily need a 30-minute meditation session to influence your physiological state.
The participants used relatively brief breathing practices.
This makes breathwork particularly interesting for moments when stress is building but you still need to function.
For example:
Before a stressful meeting
A few minutes of controlled breathing may help prevent your physiological stress response from escalating before you walk into the room.
Before public speaking
If your heart is racing and you can feel anxiety building, a simple breathing pattern may help you feel more steady before you begin.
During a difficult conversation
A few deliberately slower breaths can create a pause between feeling triggered and reacting.
After receiving stressful news
Rather than immediately moving into fast, shallow breathing, consciously slowing the breath may help reduce the physical escalation of the stress response.
Between demanding tasks
Breathwork can be used as a physiological reset, helping you transition from one task or interaction to the next.
A simple breathing practice to try
If you would like to experiment with the type of breathing used in this research, try the following:
3-second inhale
6-second exhale
Repeat every 30 seconds for 2 to 5 minutes
The researchers used a nasal inhalation followed by a slow exhalation through pursed lips.
The important point is not to force the breath.
Your breathing should remain comfortable, quiet and controlled.
If you feel air hunger, dizziness or uncomfortable tension, return to your normal breathing.
Alternatively, you could try the box breathing pattern used in the study:
4-second inhale
4-second pause
4-second exhale
4-second pause
Repeat for a few minutes.
The goal is not to take bigger breaths.
It is to create a slower, more regulated breathing pattern.
The bigger picture: learning to regulate rather than simply relax
I think this is where breathwork becomes particularly interesting.
Breathwork is often presented simply as a relaxation technique.
But learning to work with your breathing can be much more than that.
It can become a way of developing physiological awareness and self-regulation.
Instead of waiting until stress has completely overwhelmed you, you can learn to recognise the early signs:
- Your breathing becomes faster
- Your breath moves higher into your chest
- You begin holding your breath
- Your heart rate increases
- Your muscles become tense
- Your thoughts become more rapid
- You feel increasingly reactive
Breathing gives you a tool that is available in that moment.
You can use it to create a little more space.
A little more steadiness.
A little more choice in how you respond.
And perhaps that is one of the most valuable applications of functional breathwork: not eliminating stress, but helping the body respond to stress more appropriately.
The research
McAllister MJ, Martaindale MH, Sutton N, Andersen JP. Box breathing and prolonged exhalation reduces markers of physiological stress reactivity in response to a virtual Trier Social Stress Test. Comprehensive Psychoneuroendocrinology. 2026;27:100360. doi:10.1016/j.cpnec.2026.100360.
This study is open access and was supported in part by the US Department of Justice, Office of Community Oriented Policing Services.