Jet lag is a fairly common problem among people who undertake international travel, especially transmeridean travel. Jet lag is not seen if the journey does not involve transmeridean travel, even if journey is of several hours duration, e.g. traveling from London to Cape Town, a 7 hours journey.

What is jet lag?

The medical term of jet lag is “desynchronosis”. Jet lag is a condition due to alteration of normal cicardian rhythm of sleep by transmeridian air travel and there is disturbance in sleep, tiredness etc. Jet lag occurs due to transmeridian (east-west or west-east) air travel. More than 75 million people undertake transmeridian air travel annually and many of them experience jet lag.

During the time of evolution of humans, the food supply was intermittent and for survival there was need to store energy in excess of what is required for immediate use. Fat cells did the job of storing energy, which are widely distributed in adipose tissues. The fat cells can store excess energy efficiently as triglyceride and, when needed, release stored energy as free fatty acids for use at other sites. This physiologic system developed during the time of evolution acts through endocrine and neural pathways and even can permit humans to survive starvation for as long as several months. But at present era of nutritional abundance, sedentary lifestyle, and influenced importantly by genetic endowment, this physiologic system of storing energy in adipose tissues can produce obesity and adverse health consequences due to obesity.