What is the Origin of Jet Lag Syndrome?

The term is a descriptive compound of 'jet' (referring to jet aircraft travel) and 'lag' (referring to a delay or slow adjustment). It became a recognized clinical entity following the advent of commercial jet travel in the mid-20th century, which allowed for the unprecedented speed of crossing numerous meridians. The medical understanding is rooted in chronobiology, the study of biological rhythms.

What is the Mechanism of Jet Lag Syndrome?

The mechanism involves the acute mismatch between the exogenous light-dark cycle of the new time zone and the endogenous rhythm of the SCN, which controls the cyclic release of hormones like melatonin. Traveling eastward necessitates advancing the internal clock, while westward travel requires delaying it, a process that can take several days to achieve full re-entrainment. The resulting misalignment of cortisol, growth hormone, and other endocrine signals contributes to the characteristic fatigue, insomnia, and gastrointestinal distress experienced by travelers.

Jet Lag Syndrome ∞ Area

Jet Lag Syndrome

Meaning

Jet Lag Syndrome, clinically termed desynchronosis, is a temporary circadian rhythm disorder characterized by a collection of physical and mental symptoms resulting from rapid travel across multiple time zones. This physiological disruption occurs because the body’s internal master clock, the suprachiasmatic nucleus (SCN), remains synchronized to the original time zone, causing a mismatch between internal hormone cycles and the external light-dark environment. The syndrome impacts critical endocrine functions, including cortisol and melatonin release, affecting sleep quality, digestion, and cognitive performance. It is a common challenge for global travelers.