What should you know about severe jet lag symptoms?

Jet lag happens when the body clock is out of step with local day and night. Symptoms can include difficulty sleeping at the local bedtime, waking too early, daytime sleepiness, fatigue, poor concentration, mood changes, headache, and appetite or stomach upset. The [Jet Lag](/conditions/jet-lag/) page describes the condition. Severe or persistent sleep disruption can resemble [Insomnia](/conditions/insomnia/), but travel timing and time-zone changes provide useful context.

Explore [Daytime Sleepiness](/symptoms/daytime-sleepiness/), [Difficulty Sleeping](/symptoms/difficulty-sleeping/), and [Headache](/symptoms/headache/) for symptoms that may accompany the adjustment.

Set your sleep, meals, and daylight exposure around the destination time. Seek natural light during the local day, keep the sleep space dark and quiet, and use a short nap only if needed. Drink water, eat lightly if your stomach is unsettled, and avoid driving or hazardous work when very sleepy. [Insomnia Management](/treatments/lifestyle-and-wellness/insomnia-management/) may offer practical sleep strategies.

Seek urgent help for chest pain, severe breathlessness, fainting, new confusion, weakness on one side, or a sudden severe headache. Arrange medical review if sleep disruption continues after the travel adjustment period, daytime sleepiness prevents safe activities, or symptoms are worsening. A [Travel Health Consultation](/treatments/occupational-and-travel-medicine/travel-health-consultation/) can help when travel is frequent or medically complex.

Ask how to shift your schedule for the direction of travel, whether medicines or health conditions could worsen sleepiness, and whether a sleep assessment is appropriate. Share your flight dates, time-zone changes, current sleep pattern, caffeine and alcohol use, and safety-critical duties.