1) You’re thirsty AF.
Dehydration affects your body’s concentration of electrolytes, the electrically charged minerals that play a role in nerve signaling to enable many of the body’s metabolic processes. When your body is short on liquids, your kidneys, the organs responsible for moderating blood and urine volume, cry out for help: In response, the brain’s hypothalamus triggers the thirst response, which leads you fill your glass and solve your kidneys’ problems.