Why is jet lag worse when flying east?
Quick Answer
Our internal body clock runs slightly longer than 24 hours, so delaying it (flying west) is easier than advancing it (flying east).
The Full Story
The human circadian clock naturally runs on a cycle of about 24.2 hours, not exactly 24. This means it is slightly easier for the body to stay awake a little longer (as required when flying west and gaining hours) than to fall asleep earlier (as required when flying east and losing hours). Studies show travellers typically adjust about 60 to 90 minutes per day when going west but only about 40 to 60 minutes per day going east. Bright light in the morning at your destination helps reset the clock eastward, while evening light helps westward adjustment. Melatonin supplements and strategic napping can also help.
Key Facts
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Suggested video title for this topic:
"West is best β why flying east gives worse jet lag"