If You Practise Breathwork, You Should Understand Nitric Oxide.
This foundational molecule is mostly likely deficient in your body, yet amplifies Wimhof and breathwork practice
Most breathwork conversations revolve around two gases: oxygen (O₂) and carbon dioxide (CO₂).
But there is a third gas that plays an important role in what happens to your circulation during breathing, exercise and changes in oxygen availability:
Nitric oxide (NO).
NO is a tiny signalling molecule produced throughout the cardiovascular system. One of its most important functions is regulating vascular tone—helping blood vessels determine when to constrict and when to relax.
That matters because getting oxygen into your lungs is only part of the equation.
You still need blood flow to deliver that oxygen to your tissues.
Breathwork Changes O₂ and CO₂
Wim Hof-style breathing provides a particularly interesting example.
Repeated deep breathing lowers CO₂ levels and increases blood pH. This can temporarily constrict certain blood vessels, particularly in the brain.
Then comes the breath-hold.
Oxygen progressively falls while CO₂ begins rising again. This creates a temporary hypoxic stimulus and a very different vascular environment.
NO is closely involved in the body’s vascular response to changing metabolic and oxygen conditions.
One of NO’s major functions is signalling the smooth muscle surrounding blood vessels to relax:
Nitric oxide → smooth muscle relaxation → vasodilation → increased blood flow
So while breathwork manipulates O₂ and CO₂, nitric oxide is part of the vascular signalling system controlling the flow.
Your Nose Is Actually a Nitric Oxide Generator
The relationship between breathing and nitric oxide becomes even more interesting when you look at the nose.
The paranasal sinuses produce high concentrations of NO.
During nasal breathing, some of this NO is carried into the respiratory tract and lungs, where it can participate in pulmonary vascular regulation and ventilation-perfusion matching.
There’s even evidence that humming can dramatically increase nasal NO release.
One human experiment found nasal NO increased approximately 15-fold during humming compared with quiet exhalation, probably because humming rapidly exchanges air between the sinuses and nasal cavity.
In other words:
Nitric oxide isn’t separate from breathing physiology. It’s built into it.
There Is More Than One Way to Make Nitric Oxide
The body has several interconnected mechanisms involved in NO biology, but two pathways are particularly important.
The eNOS pathway
The endothelium—the inner lining of our blood vessels—produces NO using the enzyme endothelial nitric oxide synthase (eNOS).
L-arginine is the substrate, while L-citrulline can support arginine availability.
Exercise is also important. Increased blood flow creates shear stress against the endothelial wall, which stimulates endothelial NO signalling.
The nitrate–nitrite–NO pathway
There’s also another pathway that begins with dietary nitrate.
Vegetables such as rocket/arugula, beetroot and leafy greens are particularly rich sources.
Dietary nitrate is absorbed and then concentrated in saliva. Nitrate-reducing bacteria in the mouth convert:
Nitrate → Nitrite
After swallowing, nitrite can subsequently contribute to NO formation.
Importantly, the chemistry that converts nitrite toward NO becomes more favourable under lower-oxygen and acidic conditions.
This makes the pathway particularly interesting in the context of exercise and changing oxygen availability.
Breathwork + NO: Different Systems Working Together
This is why breathwork and nitric oxide optimisation shouldn’t be considered the same thing.
They’re complementary.
Breathwork → changes O₂, CO₂, pH and autonomic activity.
Nitric oxide → helps regulate vascular tone and blood flow.
Nasal breathing → introduces sinus-derived NO into the respiratory system.
Dietary nitrate → supports the nitrate–nitrite–NO pathway.
Exercise → creates shear stress that stimulates endothelial NO signalling.
The question therefore isn’t simply:
“How much oxygen am I getting?”
It should also be:
“How effectively can my vascular system respond and deliver blood where it’s needed?”
But How Do You Know If Your NO Pathway Is Working?
This is where testing becomes useful.
Nitric oxide itself is extremely short-lived, so it’s not something you can conveniently measure at home with a simple NO blood test.
However, one part of the system can be assessed using salivary nitrite test strips.
These strips measure nitrite in the saliva, which provides an indication of activity through the oral nitrate → nitrite pathway.
You place the strip against your saliva and compare the colour change with the reference chart.
This can be useful for seeing how your result responds to things such as:
nitrate-rich vegetables → beetroot/rocket → oral bacteria → salivary nitrite
You can also experiment.
Test under similar conditions on different days.
Then introduce nitrate-rich foods or nutritional support and test again later.
You may see a substantial difference in the colour of the strip.
What the Test Does NOT Tell You
This distinction is important.
A salivary nitrite strip is not a direct measurement of nitric oxide throughout your bloodstream, and it doesn’t tell you exactly how much NO your endothelium is producing through eNOS.
It primarily provides a practical window into the enterosalivary nitrate–nitrite pathway.
But that makes it useful.
Instead of simply assuming your nitrate pathway is functioning well, you can observe how your salivary nitrite responds.
Factors such as diet, oral bacteria, antibacterial mouthwash, timing and recent food intake can all influence the result.
Test. Support. Retest.
That’s far more informative than simply taking something and hoping it’s working.
Why This Becomes More Important With Age
Healthy NO signalling shouldn’t be taken for granted.
Endothelial function generally deteriorates with ageing, and reduced NO bioavailability is one feature of vascular ageing.
Oxidative stress can reduce NO availability, while impaired endothelial function can reduce the ability of blood vessels to respond appropriately to increased demand.
Healthy NO signalling contributes to:
- vascular relaxation
- blood pressure regulation
- endothelial function
- exercise blood flow
- circulation to working tissues
- pulmonary vascular regulation
- normal cardiovascular function
So whether you practise Wim Hof breathing or not, maintaining healthy nitric oxide biology is worth thinking about as you age.
How Do You Support It?
The goal isn’t simply to take a supplement.
Regular exercise supports endothelial NO production.
Nitrate-rich vegetables such as rocket, beetroot and leafy greens support the nitrate–nitrite–NO pathway.
Maintaining a healthy oral microbiome is important because oral bacteria perform the first nitrate-to-nitrite conversion.
Nasal breathing exposes the respiratory system to sinus-derived NO.
And maintaining good metabolic and cardiovascular health helps preserve endothelial function.
The goal is to support the different pathways your body uses to produce, preserve and utilise NO.
Where Ultimate 4 and Boost 3 Fit
This is where Ultimate 4 can become a practical option.
Ultimate 4 provides beetroot and arugula extracts to support the nitrate–nitrite–NO pathway alongside L-citrulline to support the arginine/eNOS pathway.
It also includes vitamin C, taurine, glycine and magnesium taurate as additional nutritional support.
And importantly, you don’t necessarily have to take it completely on faith.
Test your salivary nitrite → take Ultimate 4 → retest under comparable conditions.
For broader plant-based nutritional support, Boost 3 adds beetroot alongside spirulina, mushrooms and other plant-derived nutrients that can complement a diet aimed at supporting cardiovascular health and healthy circulation.
But the products aren’t the important lesson.
Nitric oxide is.
If you’re already exercising, eating well, practising nasal breathing or using techniques such as Wim Hof, understanding NO gives you another piece of the physiology behind what you’re trying to achieve.
We spend a lot of time talking about getting oxygen into the body.
Perhaps we should spend a little more time thinking about the signalling system helping blood flow respond to where that oxygen is needed.
O₂. CO₂. NO.
Three gases. Different roles. One interconnected system.
And unlike many areas of healthy ageing, there’s at least one part of this pathway that you can experiment with and observe at home.
Salivary nitrite strips reflect salivary nitrite and should not be interpreted as a diagnostic test or direct measurement of systemic nitric oxide. Wim Hof-style hyperventilation and breath-holding can cause dizziness or loss of consciousness. Never practise breath-holding in water, while driving or anywhere loss of consciousness could cause injury. People taking blood-pressure-lowering medicines, nitrate medications or other cardiovascular medicines should seek appropriate medical advice before using products intended to increase nitric oxide availability.
-
Humming greatly increases nasal nitric oxide
https://pubmed.ncbi.nlm.nih.gov/12119224/ -
Decreased pulmonary vascular resistance during nasal breathing
https://pubmed.ncbi.nlm.nih.gov/9715735/ -
The nitrate–nitrite–nitric oxide pathway in physiology and therapeutics
https://pubmed.ncbi.nlm.nih.gov/18167491/ -
Inhalation of nasally derived nitric oxide modulates pulmonary function in humans
https://pubmed.ncbi.nlm.nih.gov/8971255/ -
Declining nitric oxide bioavailability in cardiovascular aging
https://pubmed.ncbi.nlm.nih.gov/41953454/