Plain English Meaning

Low blood sugar. When you haven't eaten enough or have gone too long without food, your body runs short on the fuel it needs, and your brain and eyes start to underperform.

Full Definition

A medical condition in which the level of glucose (sugar) in the blood drops below the range needed for the brain and body to function normally. In pilots, hypoglycemia can cause shakiness, sweating, confusion, slowed thinking, blurred or dimmed vision, and impaired night vision, and in severe cases can lead to loss of consciousness.

Context Anchor

Encountered in discussions of night vision and pilot fitness, especially when a pilot has skipped meals, eaten poorly, or gone a long time without food before flying.

Derivation

From Greek hypo- meaning 'under' or 'below,' glykys meaning 'sweet,' and -emia meaning 'in the blood.' Literally 'low sugar in the blood,' which is exactly what the condition is.

Why Pilots Care

Hypoglycemia can quickly blur vision, slow , and reduce the ability to interpret dim lights or instruments at , raising the of or poor decisions.