Taking Flight

WE TEND TO TAKE AIR TRAVEL FOR GRANTED THESE DAYS BUT HAVE YOU EVER WONDERED WHAT HAPPENS TO YOUR BODY WHEN YOU’RE HIGH ABOVE THE EARTH? WE FIND OUT WHAT GOES ON INSIDE WHEN YOU’RE AT ALTITUDE

- Marcus Duroldt

When we take a plane trip our body takes a journey that affects our cardiovascular system, our sensory perceptions and possibly even our immune system.

In the space of just a few minutes, your body is shot into an environment whose conditions resemble those found at altitudes of 2.5km above sea level. It’s as if you’ve suddenly scaled Australia’s Mt Kosciuszko. The air pressure drops to around 750 hectopascals – a quarter lower than at sea level. For perspective, air pressure at ground level doesn’t drop below 850 hectopascals, even in the eye of the severest cyclone or hurricane. And even then this process takes at least 24 hours.

If that wasn’t enough, the airflow around your body is sometimes an icy 5°C when it leaves the air-conditioning vents. This semi-frost is designed to counter the heat radiated by your fellow passengers (as much as a 100-watt light bulb per person) and the equipment – from the boiling hot galley to the entertainment system. The air you breathe onboard a plane is usually taken from the atmosphere via a ‘tap’ in the jet engines. It heats up from -50°C to +200°C within seconds, before dropping back to zero. Meanwhile, the air humidity falls to around 10 percent or lower. Normal room humidity, in comparison, is around 60 percent – and even in the bone-dry Sahara it’s still around 20 percent. So conditions are indeed extreme when you’re on board an aircraft. But what effect do they have on us?

Is there such thing as ‘healthy’ aeroplanes?