Upset biological rhythms. For these passengers the normal rhythms of being awake and asleep become confused as, flying quickly through different time zones the clock shows a different time compared to the original starting point. Naturally the greater the time difference the greater the effects of jet-lag. The direction traveled also makes a difference: traveling east towards the rising sun increases efforts of adaptation in terms of staying awake. The opposite is true if traveling west.

An example. Traveling from Rome to Tokyo means adding on 8 hours: if departure is in the afternoon you arrive in Japan after 12 hours in the sky, the morning of the following day, whilst in Italy it's still the dead of night. Part of your normal night's sleep has therefore been skipped and it's as if you're living a full day in 48 hours! 

General malaise. Forcing our bodies to 'respect' unnatural needs comes with a heavy price. Some symptoms can be felt on the flight itself but most are noticed upon arrival. Among the most frequent are headaches, loss of appetite, insomnia, general weariness, slow reflexes, lack of concentration and above all total exhaustion.

Traveling with ease. It's important to travel comfortably under the best possible conditions, ideally stress and anxiety-free. A good idea is to relax during the days leading up to the trip, not doing anything too tiring or demanding. You need to normalize vital rhythms, maybe with the help of self-relaxation techniques and a controlled diet. Unfortunately airports aren't without their problems and delays and setbacks are par for the course.

During the flight. As soon as you get on board adjust your watch to the time at your destination. It will help you to enter into the new time zone. At mealtimes it's best to moderate your food intake, even if portions served are rarely excessively generous. It's advisable not to indulge in alcohol or fatty foods such as cheese, butter, sweets and fried foods. A heavy digestion increases the sensation of malaise. Also to be steered clear of are stimulants such as coffee, tea and coca-cola, as well as cigarettes. Drink plenty of water to avoid constipation.

When you arrive. Try to adapt to the country of arrival's different rhythms immediately: if it's still light you could go for a walk, for example, tiring yourself out with a little light exercise before going to sleep. It's best to stay up until the local time to go bed. Sleep patterns don't go back to normal for a few days but some particularly sensitive souls feel the consequences for longer. Another remedy exists to help acclimatize you however.

Melatonin. This is a hormone produced by the pineal gland at the base of the brain, used as a 'biological adjustor' in terms of the light/dark cycle. The highest concentration of this substance is found in the blood at night and it is minimal during the day.

Jet-lag remedy. Various studies have proven the benefits of taking melatonin to rebalance the sleep/awake rhythm. It is widely available at the chemist in tablet form with this substance as the main ingredient. They are normally taken an hour before going to bed. The cycle should be begun on the day of departure and continued for 3-4 days, in other words until the body has got used to the new time zone.

Side effects. Care should be taken because Melatonin is not suitable for everyone, for example those suffering from multiple sclerosis and other auto-immune diseases. Additionally people prone to depression, convulsions or neurological ailments should be careful.