What should you know about jet lag light therapy?

Light is a strong signal for the brain’s sleep-and-wake clock. Morning exposure can encourage an earlier clock, while later exposure can encourage a later clock, so the useful timing depends on whether you travelled east or west and on your sleep plan. Poor timing can make sleep harder, and a bright-light device is not suitable for everyone. Eye conditions, migraine sensitivity, bipolar disorder, and medicines that increase light sensitivity deserve discussion before use.

Plan the schedule around your destination bedtime and wake time rather than using bright light whenever you feel tired. Outdoor daylight may be enough for some travellers; others may consider a purpose-made device after professional guidance. Follow the device instructions, do not stare directly into the light, and stop if you develop eye pain, marked agitation, or a severe headache. Keep meals, activity, and sleep times aligned with local time.

Speak with a clinician before light therapy if you have an eye disorder, a mood disorder, significant migraine, or take light-sensitising medicine. Get medical help for new vision changes, severe headache, confusion, chest symptoms, or unusual mood elevation with little need for sleep. Persistent difficulty sleeping or daytime sleepiness after travel also warrants assessment.

Ask which exposure time suits the direction of travel, how bright the device should be, how long to use it, and whether your medicines or eye health change the plan. Ask what to do if sleep worsens.