In a study which took place examining the effect of exercise on obese Zucker rats it was discovered that aerobic exercise improves nitric oxide bioavailability. What we know is that nitrates such as from beets, walnuts, and certain green leafy vegetables, all contribute to boosting the natural production of nitric oxide. It is also possible to boost nitric oxide using supplements specifically formulated as "pre-workout" because these supplements deliver what is known as "the pump" during workouts.
The exact cause of nitric oxide bioavailability increase is being studied because this could lead to new prevention strategies against cardiovascular disease. In another separate study done on humans it has been shown that two weeks of supplementing with watermelon juice improves nitric oxide bioavailability but not endurance.
Angiogenesis is the mechanism the human body uses to generate new blood vessels branched from old blood vessels. Nitric oxide is thought to play a role in the development of new blood vessel genesis. At this time it isn't certain exactly how or what triggers angiogenesis but what is known is that having a greater number of blood vessel connections throughout the heart can actually allow for a natural mechanism of bypass of clogged arteries over a long period of time.
References
Bailey, S. J., Blackwell, J. R., Williams, E., Vanhatalo, A., Wylie, L. J., Winyard, P. G., & Jones, A. M. (2016). Two weeks of watermelon juice supplementation improves nitric oxide bioavailability but not endurance exercise performance in humans. Nitric Oxide, 59, 10-20.
Lemaster, K., DeVallance, E., Branyan, K., Skinner, R., Brooks, S., Asano, S., ... & Chantler, P. (2016). Aerobic Exercise Improves Nitric Oxide Bioavailability and Endothelium-Dependent Vasorelaxation in Aortic Rings of Obese Zucker Rats. The FASEB Journal, 30(1 Supplement), 1240-28.
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