They heart’s just a muscle right? Just a pump that pumps blood from the input side to the output side? So why would it matter to the pump if you’re staying hydrated this summer?
Turns out, as you dehydrate and you have less water in your body overall, the fluid volume of blood decreases as well. The solid parts of the blood (blood cells etc) stay the same while the fluid is reduced.
As a result, the blood becomes more viscous, and more like sludge. That sludge makes it harder to deliver oxygen to every cell in your body. That’s why your heart has to work harder with every stoke. It has to expel thicker blood harder, longer if it’s going to provide the same amount of oxygen to all the cells and tissues of the body.
So have a heart for your heart. Stay hydrated!