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Know Your Genes: NOS3 – “The Nitric Oxide Gene”

The Nitric Oxide Synthase 3 (NOS3) gene is associated with the synthesis of endothelial nitric oxide synthase (eNOS), an enzyme which facilitates the production of Nitric Oxide (NO). NO is shown to be associated with the widening of blood vessels by relaxing the smooth muscle cells within their walls, this has been shown to increase blood flow. Specific alleles of this gene are known to either increase or decrease the levels of eNOS during and after exercise. People with the T variant of the gene are found to synthesize lower eNOS which affects nitric oxide production, power/sprint ability and exercise-induced effects such as lowering of blood triglycerides levels.

Association with Running:  

The G allele is associated with increased muscle performance and may improve performance in power sports such as weightlifting or sprinting.  A study conducted on power and sprint athletes showed that people with the G variant of the gene were more common among power athletes than non-athletes.

Association with Omega 3 Requirement:

Omega-3 fats are associated with a reduced risk of heart disease, which in part is due to the ability to lower blood triglyceride levels. The effect of omega-3 fat on triglyceride levels has been shown to be associated with variations in a gene called NOS3. People with the T variant of the gene are associated with greater reduction of plasma triglyceride levels on consumption of Omega 3 fats.

Association with Exercise mediated stroke volume and heart rate:

This gene is associated with health benefits associated with exercise due to the role of nitric oxide in regulating vascular tone. People with the T variant have been shown to be associated with higher stroke volume and lower heart rate during exercise.

Association with Hypertension:

A study conducted on Southern Europeans found that people with the T variant had a higher risk of hypertension and diastolic blood pressure in response to high intake of Monounsaturated fatty acids (MUFA) and Saturated fatty acids (SFA). A study conducted on Indians found that people with the T variant of the gene were associated with increased of hypertension. The same study showed that there was a significant association between tobacco use and alcohol consumption among people with the G variant of the gene and hypertension. In a study conducted on Pakistanis, people with the T variant have been shown to be associated with elevated BP.






[Limitation] More likely to have reduced eNOS activity and Nitric Oxide

[Limitation] Poor power/sprint ability

[Advantage] More likely to have lower plasma triglyceride levels on higher intake of Omega 3 fats

[Limitation] More likely to have an increased risk for hypertension

  • Likely to be less effective in power related activities
  • People with elevated levels of triglycerides will benefit from consuming omega 3 fats, which will lower plasma triglyceride levels
GT Moderate reduction in eNOS and moderate power/sprint ability
  • Likely good at power based activities

[Advantage] More likely to higher eNOS activity and Nitric Oxide than people with the T variant

[Limitation] More likely to have no influence on plasma triglyceride levels on higher than recommended intake of omega 3

[Advantage] More Likely to have lower risk of hypertension

[Advantage] Better power/sprint ability

  • Likely better at Power associated activities
  • Some power based activities are throwing a ball, sprinting, bench press and deadlift
  • Tobacco chewing and alcohol consumption are associated with increased risk for hypertension. To lower risk, these practices should be avoided.


Find out which variation of the gene you carry and more at

Nutrigenetics, fitness genetics, health genetics are all nascent but rapidly growing areas within human genetics. The information provided herein is based on preliminary scientific studies and it is to be read and understood in that context.”


Xcode is a pioneer in personal genomics, focussed on enabling personalized preventive healthcare. We are dedicated to empowering physicians, wellness professionals and customers with the most validated, accurate and actionable genomic information to positively impact and improve their client’s health and quality of life.

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