Urine color as an indicator of hydration Ultrasound of the blood vessels of the neck that supports the diagnosis of severe<unk>  The hallmarks of<unk>  include thirst and neurological changes such as headaches, general discomfort, loss of appetite, decreased urine volume (unless polyuria is the cause of<unk> , confusion, unexplained tiredness, purple fingernails, and seizures. The symptoms of<unk>  become increasingly severe with greater total body water loss. A body water loss of 1-2%, considered mild<unk> , is shown to impair cognitive performance. While in people over age 50, the body's thirst sensation diminishes with age, a study found that there was no difference in fluid intake between young and old people. Many older people suffer symptoms of<unk> .<unk>  contributes to morbidity in the elderly population, especially during conditions that promote insensible free water losses, such as hot weather. A Cochrane review on this subject defined water-loss<unk>  as "people with serum osmolality of 295 mOsm/kg or more" and found that the main symptom in the elderly (people aged over 65) was fatigue.
Dehydration
Altitude sickness
Water intoxication
Postural orthostatic tachycardia syndrome  Postural orthostatic tachycardia syndrome  1
Hyperosmolar syndrome
Hypovolemia
Exercise-associated hyponatremia
Stress hyperglycemia