Nitric Oxide: Supporting Circulation with Food, Movement and a Little Humming

HealthyRetired — The Healthy Aging Project
Draft article • 6 October 2026

Beetroot, spinach and humming seem to have little in common. Yet all three appear in discussions about nitric oxide, a tiny molecule with important roles in the body. What does it do, and which habits really help?

For healthy aging, the goal is to support normal function. We do not need to chase the highest possible nitric oxide level or buy every product carrying an “NO booster” label.

What is nitric oxide?

Nitric oxide, abbreviated NO, is a short-lived signaling molecule made from one nitrogen atom and one oxygen atom. It is different from nitrous oxide, the gas sometimes called “laughing gas.”

In blood vessels, NO helps the surrounding smooth muscle relax, allowing vessels to widen and blood to flow more easily. It also participates in nerve signaling and immune defense. Its effects depend on where, when and how much is produced: more is not automatically better. [1]

NO signaling also plays a role in erections, but that does not make beetroot a proven treatment for erectile dysfunction. Persistent difficulties deserve assessment rather than a promise from a juice bottle.

Two routes to nitric oxide

The body can make NO from the amino acid L-arginine, using enzymes called nitric oxide synthases. The cells lining blood vessels use this pathway to help regulate circulation. [1]

There is also a food-related route:

Nitrate in vegetables → nitrite → nitric oxide.

Some absorbed nitrate returns to the mouth through saliva. Bacteria on the tongue convert part of it into nitrite. After swallowing, nitrite can be converted into NO in the stomach and other tissues. This pathway helps explain why our oral microbiome matters beyond teeth and gums. [2,3]

The nitrate in a vegetable is a precursor; you are not eating a ready-made supply of nitric oxide.

Beetroot and spinach: useful ingredients, not magic medicines

Beetroot and leafy greens are well-known sources of dietary nitrate. Rocket, also called arugula, lettuce and celery offer other choices. Nitrate content varies with growing conditions and storage, so a particular serving does not deliver an exact, predictable dose. [4]

Some randomized trials have found lower blood pressure after nitrate-rich beetroot juice. One four-week study involved 68 people with hypertension. However, another trial in people with treated hypertension found no blood-pressure benefit. Individual responses and study results vary. [2,5]

A trial in middle-aged and older adults also investigated increasing nitrate-rich vegetables as part of everyday eating. This is especially relevant to HealthyRetired: we can build useful foods into meals rather than treating a concentrated drink as essential. [6]

For a simple routine, rotate a serving of leafy vegetables and include beetroot when you enjoy it. These foods also provide nutrients beyond nitrate. This is a meal suggestion, not a therapeutic nitrate prescription.

Food	Easy way to use it
Beetroot	Roast or steam, then slice into a salad or blend into hummus
Spinach	Add to lentils, tofu dishes or soup; wash carefully if serving raw
Rocket/arugula	Add to a salad or scatter over a meal after cooking
Lettuce	Use as a salad base with beans, tofu or tempeh
Celery	Chop into soups, bean salads or a crunchy vegetable plate

Must we eat these vegetables raw?

No. Cooked vegetables can still contribute nitrate. Boiling and discarding the water can reduce the amount because nitrate dissolves into the cooking water. Steaming or roasting avoids that particular route of loss, although exact retention varies. [7]

There is no need to turn every meal into a chemistry experiment. Choose preparation methods that make vegetables enjoyable and easy to eat regularly.

Your mouth bacteria are part of the process

Dr Michael Greger discusses this pathway on NutritionFacts.org, including the effect of antiseptic mouthwash. In a small crossover experiment, chlorhexidine-containing antibacterial mouthwash markedly reduced the increase in blood nitrite after a nitrate dose. [3,8]

This does not mean abandoning oral hygiene. Continue brushing, cleaning between teeth and having dental care. If your dentist prescribed an antiseptic rinse, do not stop it on your own. Ask whether it is needed and for how long. Avoid assuming that every mouthwash has the same effect.

Good oral health and a functioning oral microbiome belong together.

Humming: a real effect, with a specific meaning

The sinuses contain nitric oxide. Humming creates oscillating airflow that improves gas exchange between the sinuses and nasal passages.

In a small study of ten healthy people, nitric oxide measured during nasal exhalation was about 15 times higher while humming than during quiet exhalation. That is the origin of the often-repeated “15 times more nitric oxide” claim. [9]

The crucial detail is where it was measured. This was nasal nitric oxide during a breathing maneuver. It does not demonstrate 15 times more NO throughout the body, a sustained circulation benefit, or prevention of heart disease. The original researchers called for investigation of possible therapeutic effects.

If you enjoy humming, try a few gentle repetitions:

Sit comfortably and breathe normally.
Take an easy breath through the nose, if comfortable.
Exhale with your lips closed, making a soft “mmm” sound.
Return to normal breathing between repetitions.

This is a comfort exercise, not a validated treatment dose. Do not force the breath, hold it for long periods or continue if you become dizzy. There is no need to turn yourself into a human lawnmower.

Movement supports the blood-vessel pathway

Exercise changes blood flow and the forces acting on the vessel lining. Regular aerobic training can improve NO-related vessel relaxation. A controlled study found improvement after continued aerobic exercise in people with normal or elevated blood pressure. [10]

Walking, swimming and cycling can make movement part of ordinary life. Start at a comfortable level and build gradually. For older adults, consistency and a suitable intensity matter more than pushing hard to “boost” one molecule.

What about watermelon and supplements?

Watermelon contains L-citrulline, which the body can convert into L-arginine. In a small human trial, watermelon juice increased circulating citrulline, arginine and nitrite, but did not improve endurance performance. A change in a blood marker is not automatically a meaningful health benefit. [11]

Enjoy watermelon as food. A normal serving should not be assumed to reproduce experiments using substantial quantities of juice or concentrated supplements.

Likewise, seed and nut blends can contribute protein to a varied diet, but they should not be advertised as guaranteed NO boosters. Concentrated arginine, citrulline and beetroot products deserve more caution than an ordinary meal, especially if you take medicines affecting blood pressure.

And sunshine?

As discussed in our sunlight article, UVA can release NO from stores in the skin. A small experiment found a temporary reduction in blood pressure. That does not establish deliberate UV exposure as a safe treatment: UVA also damages skin. Vegetables and appropriate movement are more practical foundations for this article. [12]

A few individual considerations

If you already have low blood pressure, feel light-headed or take blood-pressure medication, discuss concentrated nitrate products with your clinician. Do not change prescribed medication to make room for a supplement.

Spinach is high in oxalate. People with a history of calcium oxalate kidney stones may need to adjust it according to their stone-prevention plan. Kidney disease can also change suitable food choices, so a generic “more greens” recommendation may need individual advice. [13]

For everyday meals, variety is a useful starting point: leafy vegetables, beetroot, legumes and other whole foods, alongside regular movement. Humming can be an enjoyable extra, while its whole-body benefits remain unproven. Supporting circulation need not be expensive—another good fit for vivere parvo.

Sources and further reading

General information for healthy aging; not an individual treatment plan.