Jet Lag

Jet Lag Calculator

Jet lag results from  travel across multiple time zones, disrupting the body’s internal circadian rhythm and “body clock” – leaving you out of sync with local time at your destination.

It takes time to adjust naturally to the new time zone – roughly one day at your new destination for each hour of time difference, and a little longer for travelling eastbound than westbound.

Our Jet Lag Calculator can help you calculate how long it will take you to adjust to your new time zone – and back again when you come home, and can also show you the effect of simple strategies to help you adjust more quickly.

If you would like more information, bring your results with you to your travel consultation and a travel nurse can discuss how you can reduce your jet lag.

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Fleet Street Jet Lag Calculator

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What is Jet Lag?

Jet lag results from travel across multiple time zones, beyond the body's ability to adapt.

Jet lag results from rapid travel across multiple time zones, disrupting the body’s internal circadian rhythm and “body clock”, leaving you out of sync with local time at your destination. It is often made worse by the stress of travel, fatigue and loss of sleep arising from the journey itself.

Common symptoms include fatigue, insomnia, irritability, and difficulty concentrating, as well as disordered body function (such as appetite and bowel function).

The body needs time to adjust to the new time zone – roughly one day at your new destination for each hour of time difference. Children and infants are just as likely to be affected by jet lag as adults.

What are the symptoms of Jet Lag?

Symptoms of jet lag are temporary and in most cases are solely an inconvenience.

Complications of jet lag are extremely rare and are usually due to an existing medical condition. Prolonged travel across different time zones can increase the severity of the symptoms.

Symptoms include:

  • Distrubed sleep leading to daytime fatigue
  • Reduced alertness
  • Increased irritability
  • Depression
  • Headaches
  • Gastrointestinal disturbances
  • Decreased appetite

I am travelling for business, when is it best to book a business meeting?

If you need to arrange meetings or any other activities on arrival that require you to be mentally alert, pick a time that corresponds to daylight hours in your home time-zone.

Accept that your performance may be reduced through jet lag, and avoid important business activities for at least the first 24 hours following arrival.

Are you travel-ready?

Need more information?

Book a travel consultation with one of our specialist travel nurses.

During your appointment, you can discuss all your travel plans and we can advise you on how to reduce your chances of jet lag as well as go through any travel vaccinations and travel medications you should consider. This personalised service will take into account all your travel plans and we’ll create a bespoke health plan to keep you healthy throughout your travels.

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Rapid travel across different time zones is the cause of jet lag. The body will adjust to the new time zone naturally over time – at a rate of roughly one day for each hour of time difference – but whilst you are adjusting you will experience jet lag symptoms.

Give your body as many “clues” to your new time zone as you can; such as adjusting your wristwatch as soon as possible, and observing local mealtimes and bedtimes. Use our Jet Lag Calculator to explore other strategies for reducing symptoms.

Travelling east causes more problems than travelling west. This is because it is more difficult for your body clock to be advanced than delayed. It is slightly easier to adapt to a longer day than to a shorter one. Book a travel consultation to discuss how you can limit your chances of serious jet lag.

Purely from the perspective of sleep loss and jet lag, it is best to avoid night-time flights where possible, unless the flight is long enough to allow you to sleep for six hours or more, and unless you will be able to lie down.

If this is not possible, it is best to try and build a rest period on arrival into your schedule.

Melatonin is the only medication currently proven to help speed up adaptation to a new time zone, and our Jet Lag Calculator provides guidance on using it for this purpose.

Short-acting sleep medication can help reduce sleep disruption at your destination and on return, and fatigue arising from sleep loss.

Modafinil is a medicine that can reduce daytime drowsiness and increase alertness, and can sometimes be used to help cope with meetings and improve work performance in a new time zone.

All of the above, alongside other strategies, can be discussed and prescribed at a consultation with one of our Travel Medicine specialists.