Thebloodstream is a key conduit that relays biomechanical (hypertension) andbiochemical information (hypercholesterolemia) from environmental change ordisturbance (jet lag, shift work, sleep dysfunction) to the vasculature, while theremay also be direct acting clock dampeners such as aging that act on endothelialcells directly to worsen clock function [Figure 4]. This evidence concerns the gene CLOCK and familial hypercholesterolemia.