What does it do to you when you take the long-haul flights
Qantas has announced that beginning at the end of 2025, it will start flying passengers with non-stop flights from the east coast of Australia to London, which will put passengers flying for over 19 hours in a single stretch. This is in contrast to current flights, which last approximately 24 hours, but they are split into shorter sections.
It is also possible to be more tired than normal. It is due to the body’s inability to absorb more oxygen from cabin air than it can at ground level. It’s the body’s defense mechanism, which can cause you to feel tired.
The positive side is that the majority of these issues will not necessarily be more noticeable during longer flights. The main cause of these issues is when the plane descends and climbs.
You could develop blood clots.
Blood clots, which are a result of being inactive for long periods, are a major issue for people traveling. This includes lumps that develop within the legs ( deep vein thrombosis or DVT), which can spread into the lungs (where it’s known as embolism in the lungs).
If you don’t get up and move in the plane and the more of these risks you’re carrying, the more likely the possibility of blood clots becoming:
Recent immobilisations or surgeries
pregnancy or just recently had a baby
Oral contraceptive pills or hormone replacement therapy.
According to a study in 2022 that combines information from more than 18 research studies, the longer your travel time, the higher the chance of blood clots. Researchers calculated that there was a 26% increase in the risk of developing a clot for every 2 hours of travel starting at four hours.
What is the chance of clots occurring on these longer flights? We’ll never know until we begin studying the passengers on these flights.
In the meantime, until that evidence is available, the current recommendation is in effect. Be active, drink plenty of water and reduce alcohol consumption.
Read more: Explainer: what is deep vein thrombosis?
There’s also evidence for wearing compression stockings to prevent blood clots. These stockings are said to promote blood flow in the legs and to help blood return to the heart. This would normally happen by muscle contractions from moving or walking.
A 2021 Cochrane review brought together the results of nine studies with 2,637 participants randomly assigned for compression socks (or not) for flights lasting more than five hours.
No participants developed symptomatic DVTs. However, there was evidence that those who wore the stockings reduced the chance of developing clots that did not cause symptoms. And we are aware that clots can develop, grow, and move and then, eventually, cause symptoms.