Both animal and human studies have indicated a link between dehydration and hypertension.
Research has shown that people suffering from hypertension tend to have lower total body water and intracellular water, suggesting that a lack of hydration can potentially worsen hypertension.¹³
As a result of hypohydration resulting from dehydration, the volume of water in our body decreases. This directly leads to an increase of sodium and other solute concentrations in the blood.
On top of this, the increase in sodium and solutes also activates the renin-angiotensin-aldosterone system in our bodies, which results in sodium retention, further exacerbating the negative effects on blood pressure directly brought about by excess sodium.²⁹
Finally, beyond the renin-angiotensin-aldosterone system, our body also begins producing a hormone called vasopressin in response to these changes, which constricts our blood vessels and leads to higher blood pressure.⁴