Definition
Substances that increase the production and output of urine by the kidneys, causing the body to lose fluid and electrolytes. In aviation medicine, diuretics include prescribed medications used to treat conditions such as high blood pressure, as well as common dietary substances like caffeine and alcohol that have a diuretic effect.
Plain English
Things you eat, drink, or take that make you urinate more, which means you lose body fluid faster than normal.
Context Anchor
Seen in aeromedical and heat-stress discussions, especially when the handbook explains dehydration risk before or during flight.
Derivation
From the Greek 'diouretikos', meaning 'promoting urine'. The root 'ouron' means urine. Knowing this makes the meaning easy to remember: a diuretic drives urine out of the body.
Why Pilots Care
They accelerate fluid loss, raising the chance of dehydration that impairs judgment and reaction time in flight.
Intuition Check
Do not think of diuretics only as prescription “water pills.” In this context, any medicine or substance that makes you urinate more can matter because it may lower your body’s fluid level.
Example Sentence 1
Because coffee and tea are diuretics, the pilot switched to water during the long cross-country to stay properly hydrated.
Example Sentence 2
Certain blood pressure medications contain diuretics, so the pilot checked with the aviation medical examiner before flying in hot weather.