There's no doubt that flying takes its toll on the body, so the more you know about its effects, the better your chance of getting a good 40 winks.
Dr Sleep (Chris Idzikowski) conducted research into what happens to our sleeping patterns before, during and after a flight.
It was the first study of its kind to examine passengers' in-flight sleeping habits, and it revealed that, whilst many people are very aware of jet lag, only 11% of the sample adopt cues to help deal with it. This includes the use of light exposure, food, fluid, exercise or some combination of these four to try to combat the effects.
Deep in your brain resides the circadian clock (circ = about and diem = day), a 24-hour master clock governing every aspect of your body's functioning.
It synchronises all your internal systems - from sleep and wake cycle and levels of alertness to mood and digestion - so they function smoothly with each other and with the external world.
Light is one of the primary cues that the clock uses to maintain this link with the outside world. Flying across time zones puts the body into new patterns of light and activity more quickly than the body clock can adjust to it. Confusing the clock like this causes jet lag.
Though the body clock has difficulty adjusting to time zone travel, it prefers flying in an east to west direction. This is because the natural rhythm of our clock is programmed to operate on a day that's longer than 24 hours. So our internal clock can extend our day but it finds it difficult to reduce the hours in our day.
Travel fatigue is different from jetlag. It's a combination of the stress of travelling and the sleep debt you accrue whilst travelling. If you're suffering from travel fatigue, your ability to function properly can be impaired:
Everyone needs sleep. How much they need varies, but eight hours a night will usually do. Most people don't get anywhere near that amount and lost sleep becomes a 'sleep debt'.
Calculate your sleep debt by adding up the number of hours of sleep you've had over the last week from Monday to Friday. Don't include the weekend. Then think about a day when you felt alert and at your peak. How many hours of sleep did you get the night before? Multiply that number by five. Subtract that number from the first number and the number you are left with is your sleep debt. If it's positive or zero your sleep account is in the black! If it's negative, paying back your sleep debt is not difficult and you should be able to catch up again.