Circadian Rhythm
circadian rhythm
A circadian rhythm is an approximately 24-hour biological cycle that governs the sleep-wake pattern, body temperature fluctuations, and hormone secretion in living organisms.
Jet Lag
jet-lag
Overview
Jet lag (medically known as desynchronosis) is a temporary condition caused by rapid travel across multiple time zones. The body's circadian rhythm, which regulates sleep-wake cycles, hormone release, and body temperature, becomes misaligned with the local day-night cycle at the destination. Symptoms include fatigue, insomnia, difficulty concentrating, and digestive issues.
Eastward vs. Westward Travel
Traveling eastward is generally harder to adjust to than westward travel. This is because the human circadian clock naturally runs slightly longer than 24 hours, making it easier to extend the day (as in westward travel) than to shorten it. A common rule of thumb is that recovery takes approximately one day per time zone crossed when traveling east, and about two-thirds of a day per zone when heading west.
Mitigation Strategies
Effective strategies include gradually shifting sleep schedules before departure, seeking bright light exposure at strategic times, and using melatonin supplements. Staying hydrated, avoiding alcohol during flights, and timing meals to match the destination schedule can also accelerate adaptation. For short trips of 1-2 days, some travelers choose to remain on their home time zone entirely.
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