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Nitric Oxide and Vasodilation: How it Works

Nitric oxide (NO) is a gas that is synthesised by nearly every type of cell in the human body in most body tissues, including the endothelial cells within the blood vessels.

Its role in the body was not known for a long time even though scientists found small amounts of it in the air that we exhale a long time ago. Here is how it was finally discovered. Scientists analysed many fruits and vegetables to determine which compounds within them influenced heart health.

In the 1980s, they finally discovered that the body converted nitrates in certain fruits and vegetables into nitric oxide.

They also discovered that NO is an important chemical messenger in the body that plays many roles and works as a biological regulator that enables cells to communicate with each other.

In 1998, three scientists (Robert Furchgott, Lewis Ignarro, and Ferid Murad) were awarded a Nobel Prize for discovering its crucial role in maintaining blood vessel health and regulating blood pressure through vasodilation.

Benefits of improved vasodilation

Among its many roles in the body, it is now known that nitric oxide promotes the dilation of blood vessels. It works by relaxing the inner walls of blood vessels, particularly the large arteries and veins, thereby enabling them to dilate.

This enables blood to flow smoothly. In the same process, it causes blood vessels to come closer to the surface. This effect is known as vasodilation.

Nitric oxide has this effect whether it is produced by the body or is introduced into the body through foods and supplements. Here are the benefits of vasodilation.

Improved circulation

Vasodilation enables the blood to flow smoothly around the whole body, bringing more oxygen, lipids, and nutrients to each and every cell in each and every organ, muscle, and bone.

The increased blood flow carries more toxins and waste out of the body through the normal excretory organs. The resulting increase in nutrients and reduction of waste in the cells keeps the whole body in good health.

Better heart health

Vasodilation maintains heart health in two ways. By keeping blood vessels dilated, NO maintains healthy levels of blood pressure and prevents heart disease.

Also, better flow of blood ensures that heart muscles get sufficient blood and oxygen and remain healthy.

This is why doctors sometimes prescribe vasodilators (drugs that cause vasodilation) for people who have high blood pressure or heart failure.

Many of these drugs act directly on the blood vessels to dilate them. Other drugs act on the part of the nervous system that controls vasodilation and vasoconstriction.

The result is lower blood pressure or less strain on the heart muscles.

Improved brain function and memory

Improved blood flow into the brain due to vasodilation improves the oxygen, lipid, and nutrient supply to the brain. This improves memory and overall brain function. Recent scientific evidence proved that NO affects short-term memory traces.

Faster healing of ulcers

Nitric oxide accelerates the healing of ulcers through several actions. One of the ways is vasodilation which effectively improves blood flow in the mucosa. The increase in oxygen and nutrients to the ulcers accelerates their healing.

Better sexual health

Nitric oxide causes vasodilation in the sexual organs. When muscles in the penis relax, the blood vessels within the penis dilate, and there is improved flow of blood.

That way, a man who is experiencing erectile problems can achieve an erection. In women, the presence of nitric oxide relaxes the muscles around the clitoris, and the blood vessels around the clitoris dilate and fill with blood.

This way, a woman who is experiencing sexual dysfunction can achieve an arousal.

When scientists discovered the link between nitric oxide and sexual function, they developed erectile dysfunction medications like Viagra and Cialis which work by increasing nitric oxide levels in order to stimulate blood flow into sexual organs. That is why these medications work.

Improved athletic performance

Athletes benefit a lot from vasodilation that they get mostly through sports massage and NO-producing supplements. Increased vasodilation increases relaxation in the muscles and reduces pain and swelling.

It also increases blood flow into the muscles, which helps the muscles to recover fast after performance. Increased blood in the muscles also prepares athletes for better performance in exercise or competition.

With more oxygen and nutrients, the muscles perform better.

Also, more blood means the muscles relax and this reduces chances of injury.

Finally, vasodilation brings blood vessels closer to the surface which enables the blood to cool down and helps athletes to cool down faster during and after performance.

Faster Recovery

Vasodilation improves recovery. After surgery or injury, metabolic wastes and excess fluid tend to accumulate around the injured area and this increases pain and swelling.

Vasodilation improves blood flow in the injured area. The blood carries away the wastes and excess fluid from the injured area to the various excretory glands and nodes in the body.

The increased blood flow also provides the injured area with more oxygen and nutrients which help to repair the muscles, tendons or ligaments faster.

After recovery, muscles tend to be tight and restrictive and can be painful. Increasing vasodilation post-injury keeps blood flowing to the injury or surgery site and the muscles, keeping them warm and relaxed. This reduces tightness and pain.

Stronger muscles

Whether one is an athlete or not, we all want to maintain healthy muscles. Increased blood flow to the muscles provides them with more oxygen and nutrients. This prevents muscle weakening and degeneration, and maintains them in good health and strength.

Improves effectiveness of treatments

Vasodilation can improve the effects of a drug or radiation therapy. It works by increasing blood flow which increases the delivery of drugs or oxygen to the tissues that are being targeted for treatment.

Consider supplements

Nitric oxide plays many roles in the body, including vasodilation. Anyone who has high blood pressure, sexual dysfunction, or injury can lessen the problem by deliberately increasing nitric oxide in the body. This can be done by either taking citrulline or arginine supplements or by consuming foods rich in nitrates.




1. Nitric Oxide as a Signaling Molecule Nitric oxide (NO) is a gaseous signaling molecule that plays a crucial role in various physiological processes, including vasodilation, neurotransmission, and immune response regulation.

2. Vasodilation Definition Vasodilation is the widening of blood vessels, which results from the relaxation of smooth muscle cells in the vessel walls. This process increases blood flow and reduces blood pressure.

3. Endothelium-derived NO Nitric oxide is produced by endothelial cells lining the blood vessels. The enzyme endothelial nitric oxide synthase (eNOS) is responsible for converting the amino acid L-arginine into nitric oxide.

4. NO and Vasodilation Mechanism NO diffuses into the smooth muscle cells of blood vessels and activates an enzyme called guanylate cyclase, which in turn increases the production of cyclic guanosine monophosphate (cGMP). Elevated levels of cGMP cause the relaxation of smooth muscle cells, leading to vasodilation.

5. Nitroglycerin and NO Nitroglycerin, a medication used to treat angina and heart failure, is metabolized in the body to produce nitric oxide. This leads to vasodilation and increased blood flow to the heart, alleviating symptoms of chest pain.

6. NO and Blood Pressure Regulation By inducing vasodilation, nitric oxide helps maintain proper blood pressure levels. Reduced NO production or availability can contribute to hypertension and cardiovascular diseases.

7. Exercise and NO Production Physical exercise stimulates the production of nitric oxide in the body. As a result, blood vessels dilate, blood flow improves, and oxygen and nutrients are more efficiently delivered to the muscles and organs.

8. NO and Erectile Function Nitric oxide is essential for penile erection as it causes the relaxation of smooth muscle cells in the corpus cavernosum. This leads to increased blood flow and erection. Drugs like sildenafil (Viagra) work by enhancing the effects of NO on the corpus cavernosum.

9. Antioxidants and NO Antioxidants, such as vitamin C, can enhance the production and bioavailability of nitric oxide. This is because antioxidants neutralize free radicals that can otherwise react with and degrade NO, reducing its vasodilatory effects.

10. NO and Aging Aging is associated with a decline in nitric oxide production and bioavailability, which can contribute to decreased vasodilation and increased risk of cardiovascular diseases. Maintaining a healthy lifestyle, including regular exercise and a balanced diet, can help preserve NO levels and support vascular health.

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