Abstract Piezo1 channels are newly discovered ion channels which have come to the fore as players in endothelial biology. They have a key role as sensors of shear stress, a frictional force which arises in vascular biology because of blood flow. Endothelial Piezo1 channels are critical in murine embryonic development, just after the heart starts to beat and drive blood into the nascent endothelial network. In contrast they are not critical at the adult stage but they are important for performance in whole body physical activity where they have a vascular bed‐specific effect to cause mesenteric resistance artery vasoconstriction, achieved through opposition to the vasodilatory mechanism of endothelium‐derived hyperpolarization. These are our first insights into the relevance of endothelial Piezo1 channels and there is clearly much more to be done to understand the significance and underlying molecular mechanisms. The suggestion that they constitute an exercise sensor by virtue of their shear stress‐sensing capability is intriguing and could open the way to better understanding of the molecular basis of the response to exercise and determination of how the health benefits of exercise arise. Enhanced Piezo1 channel activity has been demonstrated in response to the Yoda1 molecule and this suggests the possibility for developing tools which probe and manipulate this aspect of the exercise system. Whether such agents might progress to ‘exercise pills’ and whether the existence of such pills would be desirable are matters for further work and debate. image