Chronic or repeated dehydration can cause more than thirst and tiredness. According to Mayo Clinic, long-lasting or repeated bouts of dehydration can lead to urinary tract infections, kidney stones, and even kidney failure.
Severe fluid loss can also contribute to heat injury, electrolyte imbalances that may trigger seizures, and life-threatening low blood volume shock (hypovolemic shock). Mild to moderate dehydration is usually corrected by drinking fluids, but severe dehydration needs prompt medical care.