I just re-watched this video by Dr. Greger produced a few weeks ago about the amount of nitrates from dietary sources. In it nitrates are converted to units, and 8 units seems to be the optimal amount for improvements in athletic performance and reduction in blood pressure (10mm/hg).
This leads me to another question. Do we have data indicating how many units of nitrates are produced when we exercise (say aerobic, yoga, resistance training)? Do we have data indicating about how many units are produces by a regular functioning endothelium?