The reason why it is always freezing on planes

There's a very important reason why the in-flight temperatures are kept so low in the cabin. Photo / Getty Images

It doesn't matter what time of year it is or what tropical destination you are flying to in the world, it's always winter on a plane.

Turns out, there is actually a very important reason why the in-flight temperatures are kept so low in the cabin.

A study published in American Society for Testing and Materials, Fainting Passengers: The Role of Cabin Environment, found that warmer cabin temperatures may increase the risk of fainting for some passengers.

According to the study, the likelihood of fainting is "higher aboard an aircraft than on the ground" due to "reduced pulmonary ventilation", or reduced blood flow to the brain, caused by immobility, drowsiness, and the build up of gas in the abdomen.

And in an environment that is already higher-risk, the research found that "high cabin temperatures may further trigger this reaction".

So on a flight that has hundreds of people crammed on board, whose bodies would each have different definitions of overheating, cabin crew will keep the aircraft on the cooler side to err on the side of caution.

Aside from the heightened risk of fainting, it is also safer to keep cabin temperatures lower to avoid dehydration. The air in a plane is already drying, so if the temperature dial is turned up, it would dehydrate passengers even more, making them sick and nauseas.

So next time you are freezing on a plane, keep in mind that having to put on more layers to keep warm is much easier than being sick on a long-haul flight.