Physiological & biochemical processes of the body get adjusted to a 24-hour periodicity of daylight and darkness and follow a rhythm which is generally known as body clock. When a person travels across a number of time zones in a short period of time, the body processes cannot get synchronized with the daylight-darkness periodicity of the destination and the body processes get disoriented. This condition is generally known as jetlag.

Generally long distance air travelers face this situation and hence this condition is known as jetlag. Apart from travelers some other people such as those working night shifts for long periods at a stretch or working long hours for a number of days may also be affected by jetlag. Their working conditions create an environment which has different rhythm of body activities effectively creating a different daylight-darkness cycle.

The common symptoms of being jet lagged are inability to concentration, being confused or forgetful and being irritable. Loss of appetite, mild depression and disturbed sleep pattern are also observed. Swollen or uncomfortable feet, dehydration, etc. may occur in some cases.

In case of travel it is the time zones crossed and not the length of the flight-time that matters. For instance Johannesburg to Frankfurt journey which is in the same time zone (since they lie along the same meridian) would cause no jet lag. It may cause tiredness or headache due to the length of time spent sitting up or due to low cabin pressure but no jet lag.

On the other hand a journey between New York and Los Angeles may cause jetlag. Near north and south poles, where depending on the time of year, there are extreme periods of daylight or darkness; jetlag effects can be quite severe in these areas.

You can take a few precautions to avoid being severely jet lagged. A good night’s sleep prior to a journey, having light meals and drinking plenty of non-alcoholic fluid in the aircraft helps in reducing the jetlag effects. Remove your shoes and stretch your legs to avoid swelling of the feet. Take some exercise like walking up and down the aisle, stretching, etc. to avoid discomfort.

Some people believe that drugs such as Melatonin can help in avoiding the jetlag; it is required to be taken at specific times for a few days starting with a couple of days before the journey and continuing for a few days after the journey is over. Research does not support this anti jetlag claim and on the contrary, in some cases, it may lead to worsening the effect of jetlag. In UK it is banned.

Some people mistakenly believe that sleeping pills help you get over the jetlag; you are strongly advised against it as it can cause other complications. There are anti-jetlag diets. But following the diet for a number of days is a cumbersome process and not very practical solution. “No Jet Lag”, a homeopathic drug, is said to be effective and being homeopathic medicine it is stated to be free of side effects.