Ever wondered why astronauts come back from space looking like they’ve been through a blender? Or why jet lag hits like a truck after that flight to Europe?

Turns out, travel – especially the space kind – does some wild things to our bodies.

I’ve dug into the science of what happens to humans when we’re on the move, and some of this stuff is going to blow your mind. From muscle going bye-bye in space to actual changes in your DNA, travel transforms us in ways you’d never expect.

Let’s break down what happens to our meat suits when we leave our natural habitat.

8 Scientific Studies About How Travel Wrecks (and Sometimes Improves) Your Body

Skip ahead:

• Space makes your muscles melt
• Your face gets puffy in space (weird!)
• Astronaut DNA gets freaky
• “Space fog” is real
• Your heart hates space
• Immune system goes haywire
• Space radiation = cancer risk
• Your lungs get confused

Space Makes Your Muscles Melt Away

When you’re floating around in space with no gravity to fight against, your muscles basically go on vacation. And not the good kind.

Stanford Medicine researchers found that without gravity, our skeletal muscles lose their ability to repair themselves properly. The muscle samples they sent to the International Space Station started looking suspiciously similar to muscles in older adults with sarcopenia (fancy word for muscle wasting) back on Earth.

Even with regular exercise, astronauts can’t completely stop their muscles from weakening in space.

This is a huge problem for those Mars missions everyone’s hyped about. You can’t exactly show up on the Red Planet with noodle arms and legs after 9 months in transit.

Your Face Gets Puffy in Space (Weird!)

Ever seen those pictures of astronauts with puffy faces? It’s not just bad space photography.

In space, your body’s fluids go haywire. On Earth, gravity pulls blood and fluids toward your feet. Take away gravity, and suddenly all that fluid floats upward, giving you what astronauts call “chicken legs” down below and a puffy face up top.

But it’s not just a cosmetic issue. This fluid shift does something way more concerning – it messes with your eyes. The increased pressure in your head can actually change the shape of your eyeballs, causing vision problems that can last long after returning to Earth.

Imagine coming back from space with a new glasses prescription. Talk about a souvenir!

Astronaut DNA Gets Freaky

This one is mind-blowing. NASA did a study with identical twin astronauts Scott and Mark Kelly. Scott spent a year in space while Mark stayed on Earth as the control subject.

When Scott returned, scientists found that nearly 1,000 of his genes had changed expression compared to his identical twin brother. His DNA had literally changed from being in space!

The good news? Most of these changes reverted back to normal after he returned to Earth. But some didn’t, which suggests that space travel leaves a permanent mark on your genetic code.

So technically, Scott isn’t 100% identical to his twin anymore. Space literally rewrote parts of who he is at a molecular level.

“Space Fog” is Real

Ever had brain fog after a long flight? Multiply that by 1000 and you’ve got what astronauts call “space fog.”

In space, astronauts often struggle with focus, memory, and multitasking. Part of this comes from the stress of, you know, being in the vacuum of space where one mistake could kill you. But it’s also from isolation, disrupted sleep, and the physical changes happening in their bodies.

This cognitive impairment is so significant that NASA has to design special procedures and technologies to help astronauts function effectively despite their foggy brains.

Think about how hard it is to do your job when you’re jet-lagged – now imagine trying to operate a space station with that feeling.

Your Heart Hates Space

Your cardiovascular system evolved to work against Earth’s gravity. Take away that gravity, and your heart gets confused.

Studies show that prolonged exposure to microgravity increases arterial stiffness – and that’s bad news for your heart health. Your arteries need to be flexible, not stiff.

This change in arterial stiffness means astronauts potentially face increased cardiovascular risks, which is especially concerning for long-term missions.

The heart muscle itself also changes. Without having to pump against gravity, it starts to weaken – like skipping leg day but for your most important muscle. When astronauts return to Earth, their hearts have to readjust, which can lead to dizziness and fainting.

Basically, space makes you temporarily heart-weak. Not great!

Immune System Goes Haywire

Your immune system – the thing that keeps you from dying from the common cold – acts differently in space.

Space travel alters immune function, potentially making astronauts more susceptible to infections or even autoimmune diseases. The stress, radiation, and microgravity all contribute to these changes.

Strangely though, astronauts don’t get sick more often when they return to Earth, which suggests that their innate immunity (the first-line defense) stays intact even if other parts of the immune system are compromised.

Scientists are still studying the long-term effects, but it seems like your body’s defensive army gets a bit disorganized in the cosmos. They’re still fighting for you, just not as efficiently as they could be on Earth.

So no, space probably won’t give you the equivalent of space AIDS, but your immune system definitely isn’t operating at peak performance up there.

Space Radiation = Cancer Risk

Earth’s magnetic field is like a force field that protects us from deadly space radiation. When astronauts leave that protection, they’re exposed to levels of ionizing radiation that would make your Geiger counter freak out.

This increased radiation exposure raises the risk of cancer and other degenerative diseases. It’s one of the biggest health concerns for deep space missions.

For a Mars mission, astronauts would be exposed to radiation levels that exceed NASA’s career limits. That’s why there’s so much research going into radiation shielding technologies.

Every day in space is basically like getting dozens of X-rays without the lead apron protection. And unlike other space health issues, this one doesn’t go away when you return to Earth – the DNA damage from radiation can lead to cancer years or even decades later.

Your Lungs Get Confused

In space, your diaphragm and abdomen shift upward because there’s no gravity pulling them down. This affects your lung capacity and how you breathe.

Without gravity, the distribution of air in your lungs changes, leading to reduced volumes and altered breathing patterns. It’s not immediately dangerous, but it does mean astronauts aren’t getting optimal oxygen exchange.

These respiratory changes are important for understanding how astronauts might adapt to long-duration missions and how to maintain lung health in space.

When you return to Earth, your lungs have to remember how to work with gravity again, which can lead to shortness of breath and reduced exercise capacity for a while. Imagine forgetting how to breathe properly – that’s basically what happens!

So if you ever meet a freshly-returned astronaut who seems out of breath, cut them some slack – their lungs are literally relearning how to function on Earth.

In Summary

Travel – especially the space kind – transforms our bodies in profound ways. From melting muscles to changing DNA, the effects are way more dramatic than just jet lag and airplane ear.

As we push toward Mars and beyond, understanding these biological changes is critical for keeping astronauts healthy. And interestingly, this research doesn’t just help space travelers – it’s giving us insights into aging and health conditions right here on Earth.

So next time you’re complaining about being cramped in economy class, just remember – at least your DNA isn’t mutating and your face isn’t puffing up like a balloon.

Unless you’re flying Spirit Airlines. Then all bets are off.