When blood flows slowly, it triggers a specific chain of molecular events that turns off an important enzyme that normally keeps blood vessels healthy and protected from inflammation and plaque buildup.

Scientists found that a specific signaling pathway called ERK1/2 is responsible for how blood flow changes affect an enzyme that controls nitric oxide production, and blocking this pathway stops the negative effects of low blood flow on nitric oxide.

When blood vessels experience low blood flow (low shear stress), a protein called Akt helps trigger a process that produces nitric oxide, which keeps blood vessels healthy. But when we block Akt, the blood vessel's ability to produce nitric oxide gets even worse.

When you walk, the movement of blood through your blood vessels creates a gentle force called shear stress. This triggers your blood vessel walls to produce more of a molecule called nitric oxide, which widens your blood vessels and helps prevent blood clots that can lead to heart disease.

When blood flows gently through veins, it turns on certain chemical switches on an enzyme called eNOS at two specific locations (Ser1177 and Thr495), but turns off a different switch at another location (Ser633) in the cells that line umbilical veins.