Perth to London flights: Qantas use science to beat jet lag on ultra-long-haul flights

A wave of ultra-long flights that will get you halfway around the world in one hop is pushing airlines to deal with the one extra you can't escape: Relentless insomnia, debilitating fatigue and tormented bowels, better known as jet lag.

Qantas, which will start the first non-stop service between Australia and Europe in March, is working with scientists in Sydney to discover ways to limit body-clock breakdown on the 17-hour flight. They've tried to make the colour and intensity of the jet's interior lights mimic dawn and dusk. Cabin temperatures and specially made meals will aim to put passengers to sleep or keep them awake-depending on the time at the destination.

The Perth-London route is the latest endurance test as new aircraft technologies stretch the time a plane can stay profitably in the air. Emirates Airline, Qatar Airways and United Airlines are part of the movement, with flights from the Middle East to New Zealand or Houston to Sydney. The delivery of a new Airbus model later this year will allow Singapore Airlines to resume its 19-hour marathon from Singapore to New York, an epic stress test for mind and body.

Key to the problem is circadian disruption-messing with the internal body clock that regulates everything from brainwave activity to hormone production and cell regeneration.

The main cue for resetting that clock is light, said Steve Simpson, academic director of the Charles Perkins Centre, which is carrying out the research with Sydney-based Qantas. But there's a baked-in biological catch: the clock can only reset by about 90 minutes a day, even in the right conditions. An ill-timed dose of sunshine or a badly chosen snack at the wrong hour can mean days of suffering, he said.

"What you can do is make sure you're pushing as quickly as you can to the destination time zone and getting the timing of things right," said Simpson. "The way you feel, the way you function-mentally through to bowel movements - is all ultimately controlled by your body-clock."

The Qantas tie-up with psychologists, nutritionists and sleep experts at the University of Sydney's Charles Perkins Centre highlights an uncomfortable truth about ultra-long-haul jet travel: there's no way to completely avoid jet lag. But to fill the new long-range jets, Qantas and rivals like Qatar Airways, which flies from Doha to Auckland, need humans to better tolerate the effects of crossing the world in less than a day.

For airlines, the stakes are huge. Qantas is taking eight 787-9 Boeing Dreamliners and has options and rights on another 45, a total investment of about $US15 billion at current prices. Singapore Air has ordered seven ultra-long range A350-900s from Airbus, listed as being worth about $US317 million each.