18 / 20
Which of the following statements is true regarding the human’s ability to deal with circadian dysrhythmia, better known as ‘jetlag’?
  • A
    The human’s rate of adaptation is independent of the direction and duration of travel.
  • B
    The rate of adaptation depends on the number of time zones crossed and the direction of travel.
  • C
    There is a prescriptive formula for calculating a precise number of days needed for circadian adaptation.
  • D
    Circadian adaptation is less likely to occur during long&haul trips of more than 3 days.

Refer to figure.

JET LAG (CIRCADIAN DISRHYTHMIA)

Crossing time zones is a way of life for long-haul aircrew, and the time zone shifts can lead to a cumulative sleep deprivation. The shifting of zeitgebers will help to resynchronize to the new local time but it is a slow process. Although every person is different, the body will require approximately 1 to 1.5 days per hour of time difference to adjust to a new local time. Furthermore, the body has more difficulty travelling eastbound than westbound. This is because of the length of the free-running rhythm (25 hours). When travelling eastbound, the perceived day becomes shorter because of the movement of the sun. Lengthening a day is less troublesome than shortening it. Thus the rate of adaptation depends on the number of time zones crossed and the direction of travel.

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.