Can lighting affect jetlag?
Light hitting the retina of the eye signals the hypothalamus to tell the pineal gland in the brain to reduce the production of melatonin – the hormone that produces restful sleep, and which can be taken as a supplement. Keeping busy so you don’t fall asleep before the locals is worth striving for.
Exposure to natural light in the afternoon and evening will help westward travellers reset to later time zones; getting out into the morning sunshine will help eastward travellers adjust to earlier time zones – this is unless you’ve travelled more than eight time zones, in which case the eye and brain may misinterpret early morning light for dusk.
Long-haul easterly travellers should consider wearing sunglasses and avoid bright sunshine in the morning but allow plenty of sun exposure in the late afternoon for the first several days. Westward travellers should avoid the sun for the few hours before dark. Obviously care needs to be taken to avoid sunburn, and travellers should aim to make gradual shifts to daily routines including to meals. Some travellers find apps help with this process.