Complications and Risks of Jet Lag

Jet lag itself is temporary, but long journeys and disturbed sleep carry some risks.

Blood clots (deep vein thrombosis)

Long periods of sitting, dry air and dehydration raise the risk of clots in the legs, especially on flights longer than 4 hours.

• Higher risk: previous clot, recent surgery or injury, pregnancy, cancer, hormone medicines, obesity, older age and clotting disorders
• Warning signs: pain, swelling, warmth or redness in one calf or leg
• Emergency signs: sudden chest pain, breathlessness or coughing blood. Call 112.
• Prevention: walk often, do calf exercises, drink water, avoid alcohol and ask about compression stockings or medicine if you are high risk

Accidents from drowsiness

Sleepiness reduces reaction time. Avoid driving or operating machinery until rested.

Sleep and mood problems

Frequent travel with little recovery can lead to long-lasting insomnia, irritability, anxiety or low mood. Seek help if symptoms last more than 2 to 3 weeks.

Effect on existing conditions

• Diabetes: meal and medicine timing changes can cause high or low sugar. Plan with your doctor.
• Epilepsy: sleep loss can trigger seizures. Keep medicine times and ask your doctor.
• Heart, blood pressure and mental health conditions: sleep loss may make them worse.
• Medicines taken on a schedule may need a timing plan.

Digestive upset

Constipation, diarrhoea and indigestion can follow disrupted meals and unfamiliar food.

Key point

The main risks are clots on long flights and tiredness-related accidents. Know the warning signs and plan ahead.

Before your appointment

Note where and when you travelled, how many time zones you crossed, and how long your sleep problems have lasted. List all medicines, melatonin, herbs and supplements you take, and your caffeine and alcohol use. Mention snoring, low mood, anxiety, leg pain or swelling, and any existing conditions such as diabetes or epilepsy. If you are pregnant or travelling with a child, say so. Ask about safe sleep aids and the warning signs that need urgent care. Call 112 for chest pain or severe breathlessness.