What might happen to your body on a 19 hour flight from London to Sydney?

22nd Aug 19 | Lifestyle

Ultra-long haul flights from London to the east coast of Australia could be coming soon.

Qantas dispute

If you hate the dreaded stopover on a long-haul flight, you could be in luck as airline Qantas is trialling non-stop commercial flights from Sydney to London and New York.

It comes as part of so-called Project Sunrise – Qantas’ goal to operate regular, non-stop commercial flights from the east coast of Australia (Brisbane, Sydney and Melbourne) to London and NYC, and in doing so, overcome “the final frontier in aviation” – according to Qantas chief executive Alan Joyce.

Plans for these non-stop routes are in the early stages: Qantas has scheduled the trial flights for October, November and December, with a maximum of 40 people on board – mostly Qantas employees. Scientists will monitor sleep patterns, food and drink consumption, lighting, physical movement and in-flight entertainment, to assess the impact on health and the body clock.

Joyce says: “Ultra-long haul flying presents a lot of common-sense questions about the comfort and wellbeing of passengers and crew. These flights are going to provide invaluable data to help answer them. For customers, the key will be minimising jet lag and creating an environment where they are looking forward to a restful, enjoyable flight.”

While we wait for the tests to be done and the research to be released, we asked Dr Diana Gall, from Doctor-4-U, what effect ultra-long haul flights might have on your body, and how this differs from the average long-haul flight.

“We all know how uncomfortable long flights can be – the stress of arriving on time and getting through check-in, worrying you’ve forgotten something, tiredness, and a lack of leg-room as you sit down and have your ears pop for the next 12 hours,” says Gall. Just imagine adding an extra seven hours on top…

Jetlag and sleep

Modern Family Sleep GIF by ABC Network - Find & Share on GIPHY

“Jetlag will likely be worse,” says Gall. She explains that jetlag is when “your body gets used to a new time zone, so expect that tiredness to stay with you for a couple days as your cortisol levels return to normal.

“Cortisol affects your physical functioning and is low and high at different times of day, so in short, if it’s low during the day when you need it to be high, and high at night, when you want it to be low, you’re not going to be performing at your peak.”

You’re likely to feel pretty out of it during the flight itself too. “With the usual tiredness that accompanies any form of long-distance travelling, the pressurised cabin means you’ll be getting less oxygen and as a result, become more tired,” Gall explains. “The lack of movement on a long haul flight only makes this worse by slowing down the flow of blood around your body, meaning oxygen is moving at a slower pace.”


With an ultra-long haul flight, Gall says: “Blood clots are more likely to form – though it’s unlikely we’ll see any significant uptick in clots, as they are usually small and will sometimes disappear by themselves.”

The reason clots can form when flying is down to the fact you’re sat in the same place for hours on end. “The lack of movement while flying allows for blood stagnation, which increases the risk of clots,” Gall explains. “I recommend getting up as often as possible, or doing exercises while sat down that mimic walking, such as calf contractions.

“Tiny clots developed from flying are able to cause larger clots. Although the chances are low and it is rarely fatal, the chances increase with longer haul flights.”

Those who are vulnerable to developing blood clots – which Gall says are “women in the early stages of pregnancy, those recovering from a recent operation, people with certain genetic disorders, and smokers” – should be particularly careful about undertaking such a long flight.

Gall recommends staying hydrated on an ultra-long haul flight is important too, as “dehydration can cause the blood to thicken”. She adds: “Once off the flight, try and do something to get the blood pumping around your body, such as walking up a flight of stairs.”

© Press Association 2019