I guess I will just keep posting all this until in sinks in. There is a very good reason something above 54% is flagged. Reasonable risk. Focus on blood viscosity not just hematocrit. See all my threads on this interested reader. If you dabble in AAS, I would recommend considering low dose aspirin.
When applying Poiseuille’s Law to the cardiovascular system, one must consider the radius and the length of the vessels, and the viscosity of the blood. The dimensions of the vascular system (most notably the radius, which is raised to the fourth power) play a more important role in determining vascular resistance than blood viscosity does. However, several works conducted in the past 10–15 years have shown that, in a physiological context, the parameters of this equation cannot be considered to be truly independent of each other. This is because vessels are not rigid tubes; they can change their diameters in response to various physiological stimuli. One of the most important molecules that promotes an augmentation in vascular diameter (i.e., vasodilation) is nitric oxide (NO). Martini et al. (2005), Tsai et al. (2005), Intaglietta (2009), and Sriram et al. (2012) showed that mild to moderate increases in hematocrit and blood viscosity did not result in a rise in vascular resistance or blood pressure, but actually caused the opposite effect. They also showed that increasing blood viscosity promoted the activation of endothelial NO-synthase through shear stress-dependent mechanisms, resulting in higher NO production, compensatory vasodilation, and decreased arterial pressure. However, evidence shows that these vascular adaptations can only occur in a functioning vascular system with a healthy endothelium. When vascular dysfunction is present, vasodilation is impaired. Therefore, a rise in blood viscosity is not accompanied by an increase in vasodilation. As a result, vascular resistance and arterial pressure increase (Vazquez et al., 2010; Salazar Vazquez et al., 2011). Although the role of blood viscosity in vascular adaptations is often ignored, these studies clearly demonstrate that vascular geometry and blood viscosity should not be considered separately when studying the regulation of vascular resistance in healthy populations or in people with cardiovascular diseases.