What happens to your body in the air?

When you fly, your circulation becomes impaired for two reasons: 

1. You're sitting for prolonged periods of time in unnatural, cramped positions 
2. Your blood oxygen levels decrease because of the cabin pressure.

Reduced blood oxygen levels are also responsible for the fatigue you experience during your flight. 

These two factors cause blood to pool in your legs and circulation to slow.

If you're a flight crew member and think you're safe because you're standing rather than sitting, think again. The same thing can happen when you're standing on your feet for too long.

Blood circulation is essential for your overall health, as it's responsible for spreading oxygen and nutrients throughout your entire body.

When circulation is impaired, blood pools in your leg veins, contributing to foot swelling by forcing fluids out of the blood and into the surrounding tissue.

More serious problems like varicose veins or blood clots can also result.

Scientists now understand and agree that certain genes affect how fast we age—and it appears the more someone travels by air, the faster they age. 

"Frequent flying can lead to chronic jet lag, which can cause memory impairment and has been linked in studies to disrupting gene expression that influences aging and the immune system, and increased risk of heart attack or stroke." 

Cabin air is dryer than the Sahara Desert. Seriously. 

You can expect a typical passenger aircraft to have about 12% humidity. The Sahara Desert sees about 25% humidity.

It has to be this way; to support a more comfortable humidity level, the aircraft would have to carry gallons of heavy, expensive water, and would be at risk for excess condensation which can be damaging and corrosive to the parts. 

But knowing this doesn’t make it any less harmful to your hydration levels.

When you fly, you likely experience some side effects of dehydration. Dry, cracked skin, chapped lips, peeling cuticles, and even nose bleeds are common after spending even a short period of time in the air. 

Dehydration can also cause headaches, digestive issues, and fatigue.

Having dehydrated mucous membranes (especially in the nose) leaves us more vulnerable to airborne viruses as well. 

You can imagine that spending hours in a confined space, with hundreds of strangers from all around the world, all while breathing in recycled air can impact your immune system.

And it's not just your imagination:

The likelihood that you will catch a cold is 100 times higher on an airplane. 

That's because not only are you exposed to tons of germs being in close quarters with hundreds of strangers, but the fatigue from reduced oxygen levels and jet lag can switch off immune system response. 

The dry cabin air also causes swelling of the mucous membranes, compromising their ability to protect you.

This means that frequent flyers have a suppressed immune system and therefore aren't as well equipped to fight off colds and viruses compared to people who travel less frequently. 

Cosmic radiation is radiation from the sun. At ground level this isn’t a problem, because the atmosphere provides somewhat of a protective barrier.

Cosmic radiation is radiation from the sun. At ground level this isn’t a problem, because the atmosphere provides somewhat of a protective barrier.
“You can’t see it or feel them, but at any given moment, tens of thousands of highly charged particles are soaring through space and slamming into Earth from all directions.

These particles, sometimes called cosmic rays or cosmic ionizing radiation, originate from the farthest reaches of the Milky Way. They’re bits and pieces of atomic cores shot to nearly light-speed by black holes and exploding stars, and they smash into (and through) anything and everything in their way.

With that incredible speed and energy, it’s no surprise cosmic rays can easily penetrate the human body and, in the process, pose risks to our health. Their damage to tissues and DNA have been linked to cancer and reproductive problems, for example.”

When you fly, your body goes into an immediate state of stress.  

When we're stressed, all of our body's energy goes to support our vital functions - like breathing and keeping our heart beating.

What does this mean for digestion? Well, the blood in our digestive tract is rerouted to support our vital functions so there is a lot less energy to digest the food you eat.

Your under-functioning digestive system will have a harder time digesting the unhealthy, nutrient depleted plane food, and the air pressure changes cause build-ups of gas -- it's clear why we feel bloated and experience all sorts of digestive disturbances while we fly.