What is a common definition of jet lag?

Jet lag is most commonly defined as a temporary sleep disorder that occurs when a person travels across multiple time zones, disrupting their body's internal clock, known as the circadian rhythm. This rhythm regulates the sleep-wake cycle and is influenced by the natural light and darkness in a person's environment. When you travel to a different time zone, your body may continue to operate on its original schedule, leading to feelings of fatigue, difficulty concentrating, and other symptoms associated with misalignment between your internal clock and the external environment.

The other options focus on metabolic and digestive rhythms, which are also important aspects of overall well-being but do not specifically relate to the phenomenon of jet lag. Jet lag primarily involves the disruption of the circadian rhythm, which encompasses not only sleep patterns but also the biological processes tied to the day-night cycle. Thus, understanding jet lag in the context of circadian rhythm is essential for addressing and managing its effects on travelers.