Jet lag — officially known as desynchronosis — is what happens when your body's internal clock is misaligned with the external environment at your destination.
The Biology of Jet Lag
Your body runs on a circadian rhythm — a roughly 24-hour internal clock that regulates sleep-wake cycles, hormone release, body temperature, and dozens of other biological processes. When you fly across time zones quickly, your clock is still running on your origin timezone while your environment demands adaptation to a new one.
Evidence-Based Strategies
Light Exposure Management: The most powerful tool for resetting your clock is strategic light exposure. Get outdoor daylight exposure during the morning for eastward travel, or afternoon/evening for westward travel.
Melatonin: Small doses (0.5mg–3mg) taken at your destination's bedtime can accelerate clock adjustment. Research supports its effectiveness, particularly for eastward travel.
Hydration: Arriving dehydrated worsens jet lag symptoms. Drink consistently throughout the flight and avoid alcohol.