Does low oxygen in planes cause jetlag?

Thanks to Malcolm von Schantz for the answer!

James - In the literal sense, jet lag might refer, as Alan writes on our forum, to a loss of synchrony between the travellers' circadian rhythms and the habits of the people at his destination. In other words, when you travel across multiple time zones in a relatively short period of time, so the length of a flight, your body's internal clock or circadian rhythm might take a few days to adjust to your new bedtime. But some people's definition of jet lag might include other components. Here's Malcolm von Schantz, Professor of Chronobiology at Northumbria University.

Malcolm - So if I may answer your last question first, do you get jet lag after travelling within the same time zone, say from Amsterdam to Johannesburg? You do not get jet lag in the formal sense because you haven't travelled across different time zones. There is no body clock disruption that will prevent you from falling asleep. But then there are the general consequences of sitting in a metal tube at a high elevation and most of them you can't do anything about and they affect everybody. Aircraft are pressurised so they contain much more oxygen inside than there is outside of those elevations. It's impossible to pressurise them at quite the same level as we experience at sea level. So there is less oxygen in the aircraft than there is on the ground. And the result of that is that our lungs have to work harder to keep our blood oxygenated. There are also other effects of that which are somewhat uncomfortable, such as it causes our stomach, our intestine to bloat up.

James - What's more, the drier air you find in planes can also leave your skin dehydrated and cause irritation in your respiratory system.

Malcolm - And then there is another really interesting question which takes me way back. What about smoking in the cabin? And I'm old enough to remember that and it was horrible on a long haul flight as a non-smoker and that certainly will have made it worse because of the nicotine and carbon monoxide and god knows what that forms part of cigarette smoke in addition to the lower oxygen level. Another improvement with modern air travel is the new aircraft models which are made of essentially a composite instead of metal. And that means that it's possible to operate those with a higher cabin pressure and also with higher humidity than earlier aircraft model.

James - So Mark, you will suffer less jet lag if you take a flight with minimal disruption to your circadian rhythm. And thanks to the smoking ban and improvements to aircraft design, other adverse health effects of flying induced partly by the lower levels of oxygen have been mitigated.