The human body is carefully crafted to survive and thrive under the conditions of planet Earth. So what happens when the human body is transported well beyond the confines of our home planet into the unknowns of outer space?

Today we’re going to explore the challenges and hazards of space travel to our Earth-dwelling bodies. While we’re still discovering exactly what the short-term and long-term effects of space travel are on our health, we do know for certain that there are several real and significant hazards of human space flight. Let’s dive in.

What Happens to the Human Body in Space?

The answer to this question is – it’s complicated. What exactly happens to the human body in space is something we’re still learning about. But considering that advances in technology are bringing us closer to a reality where civilian and even private space travel become the norm, it’s more important than ever for us to determine the health hazards of human space flight.

While we may still have more questions than answers when it comes to the long-term effects, we do know for certain that traveling through space presents its own set of dangers and challenges. So let’s explore the top 5 health hazards of outer space. 

Outer Space Hazard #1: Lack of Gravity

Here on planet Earth, our bodies are constantly battling the pull of gravity. And this constant mechanical load to our muscles and bones forces them to stay dense, stable, and strong. Gravity also plays an important role in how the fluids within our bodies are distributed – with the force of gravity pooling more of our fluids in our lower extremities. 

But if we remove gravity from the equation, it can shift our bodies and cause:

Decreased Bone Density and Loss of Muscle Mass

Loss of bone density and muscle mass has been a long-standing and well-documented concern for astronauts returning home from space travel. Without the constant tug of gravity applying force against your musculoskeletal system, your muscles and bones inevitably become weaker. This causes your muscles to begin deteriorating and your bones to become more porous and fragile.¹

Redistribution of Fluids: 

In space, your body's fluids are no longer confined by the rules of gravity – allowing them to redistribute throughout your body. As a result, the fluid that typically pools in your lower extremities is allowed to shift upwards. This causes congestion of your cerebral venous system and can impede the normal flow of your cerebral spinal fluid. 

This can cause increased intracranial pressure and a condition known as Spaceflight-Associated Neuro-ocular Syndrome, or SANS. You see, without normal gravity, fluids begin to fill up the cavities in your brain, creating additional pressure that pushes against your brain and eyeballs causing:²

• Swelling of the optic disc and retinal nerve fiber layer
• Folds or wrinkles in the retina 
• Flattening of the spherical shape of the eyeball
• Refractive errors or blurry vision

While the initial puffiness seen after space travel usually resides rather quickly, the fluid shifts seen in the cerebrospinal fluid that surrounds your brain can sometimes take months or even years to return to normal after a long trip to outer space.

Outer Space Hazard #2: Radiation

Earth is surrounded by a protective magnetic field, or magnetosphere, that deflects much of the radiation from outer space. So when astronauts enter space, they sit outside of Earth’s protective magnetic field and are exposed to exponentially higher doses of radiation. These galactic cosmic rays and solar particles contain harmful ions that are capable of producing significantly more radiation damage than terrestrial forms of radiation seen on Earth.^3,4 

These highly charged radioactive particles radiating from the sun, stars, and beyond penetrate deep into astronauts’ bodies and can cause cellular damage leading to serious problems like:

• Increased risk of cancer
• Radiation sickness
• Cataracts
• Damage to the central nervous system
• Altered cognitive function
• Reduced motor function 
• Behavioral changes

The exact amount of radiation astronauts are exposed to can vary depending on the length of their mission, how far from the Earth's magnetic field they travel, and the level of shielding their spacecraft affords.

Outer Space Hazard #3: Disrupted Sleep and Circadian Rhythm

Down here on Earth, our bodies are to some extent synchronized with the rising and setting of the sun – hardwiring our bodies for a roughly 24-hour circadian or sleep rhythm. But as astronauts orbit around Earth, they can experience sunrise and sunset as often as every 45 minutes. This circadian misalignment paired with the inevitable sleep disturbances that come with living in a spacecraft (like noise and temperature shifts) can throw astronauts' sleep cycles massively out of whack.⁵ 

And anyone who’s ever pulled an all-nighter or experienced the misery of jet lag after traveling to a different time zone can attest to just how disruptive sleep deprivation can be – especially in a high-stakes environment like in a spaceship orbiting Earth!

Outer Space Hazard #4: Isolation and Confinement

One of the most critical components of a space mission is assembling a cohesive crew of astronauts that can tolerate being crammed into a spacecraft together for months – or even years – at a time. But even the most cohesive, close-knit crews can struggle with being confined to tight quarters with a group of co-workers for an extended period of time. 

On top of being cooped up in a spaceship, space missions require spending a significant amount of time away from family, friends, and loved ones.⁶ So it’s no surprise that space missions can take an emotional toll on many crew members.

Outer Space Hazard #5: Altered Microbiome

Your microbiome is the conglomeration of microscopic organisms that reside on and in your body. These microbes play a critical role in nearly every facet of your health – from digestion to skin health and from mood to immunity. Going into outer space can majorly disrupt this delicate ecosystem.

A number of factors can contribute to this alteration of the microbiome while in space, including:⁷

• Increased exposure to radiation
• Sleep deprivation and an altered sleep rhythm
• Elevated stress levels
• A change in diet and lack of fresh food

Gut dysbiosis – or a disrupted microbiome – can manifest as a number of different conditions and is thought to be the root cause of certain health issues commonly seen in astronauts like episodes of hypersensitivity and skin rashes.⁸  

Functional Medicine Health Hacks for Aspiring Astronauts

If you’re a veteran astronaut or aspiring to take a trip to outer space in the future, there are a number of ways you can prepare your body and ensure you’re in tip-top shape before, during, and after your expedition. My best functional medicine hacks for current and aspiring astronauts are:

Show Your Gut Some Love

The health of your gut is without a doubt one of the most potent dictators of your overall health and well-being. Without a healthy, happy gut, the rest of your body simply can’t function properly. And considering space travel can put a damper on your microbiome, it’s critical to be proactive.

Some simple ways to show your gut some love include:

• Eat a well-rounded anti-inflammatory diet full of fresh veggies and fruits, healthy fats, and high-quality protein. While the menu may be more limited during your space mission, there are plenty of healthy food choices that can survive the long space voyage.
• Avoid gut-damaging inflammatory foods that contain processed oils, refined sugar, preservatives, and other chemicals.
• Consistently re-introduce beneficial strains of bacteria to maintain a thriving and diverse microbiome. Simply incorporating a daily probiotic along with a dose of spore probiotics is all you really need. 
• Keep your gut microbes happy and well-fed by incorporating a prebiotic like Bind-Aid.

But what you put in your body isn’t the only thing that impacts your gut health. The other health hacks on this list will also help support a happy and healthy tummy.

Practice Good Sleep Hygiene

Sleep hygiene simply refers to the habits and routines you incorporate to promote quality, consistent, and uninterrupted sleep. Practicing good sleep hygiene is important down here on Earth, but is doubly important in space when you can’t rely on a normal sleep-wake cycle.

Some ways to practice good sleep hygiene include: 

• Develop a bedtime ritual or routine to signal to your brain it’s time to wind down
• Reduce screen time before bed
• Keep your sleeping area dark and quiet
• Avoid eating a large meal close to bedtime
• Create a sleep schedule by falling asleep and waking up at roughly the same time each day and stick to it

For a deeper look at our sleep cycles and how you can get a better night's sleep, click here to read my article all about sleep. 

Incorporate Meditation

Meditation is hands-down one of the most powerful tools for supporting mental health while releasing and coping with stress. And considering your emotional well-being and stress levels impact all facets of your health, it’s no surprise that the benefits of meditation trickle down to every cell in your body. 

Creating and incorporating a daily meditation practice can work wonders for improving your mental and physical health and I strongly encourage everyone to give it try. If you’re new to meditation and not sure where to start, head over and check out my article Be Happier and Less Anxious with 7 Minutes a Day.

Get Moving

Our bodies are designed to move. Incorporating intentional movement and exercise every day is important for:

• Bone density and muscle mass
• Heart and lung health 
• Digestion
• Detoxification
• Mental health and stress

Finding ways to move every single day – even if it's just a brisk walk or a simple stretching routine – can go a long way in promoting and preserving your health whether you’re on Earth or in space. In fact, exercise is so beneficial that resistance training has been incorporated as an important component of every astronaut's time in space.

Mitigate the Effects of Atmospheric Radiation

It’s impossible to eradicate exposure to radiation whether you’re on Earth or floating around in outer space. Fortunately, there are steps you can take to lower your risk and help your body better cope with the unavoidable radiation. Here’s what you can do: 

• Minimize exposure as much as realistically possible. That might mean not keeping your cell phone in your pocket or turning off electronics when not in use.
• Invest in a shielding device that can help transform harmful radiation into more biologically friendly forms that your body is more equipped to handle. Click here to read more about EMF-shielding devices.
• Incorporate a radiation mitigating supplement like Ion Shield. Ion Shield is a carefully calibrated concoction of botanicals, herbal extracts, and biologically-active nutrients specifically designed to protect your body from the free radicals produced by environmental radiation. You can find it on my online store and even get 10% off your first order by clicking here.
• Minimize your toxic burden. Radiation is a type of harmful toxin that your body must process. Minimizing your overall toxic burden will ensure your body has the resources it needs to cope with radiation exposure. 

Radiation is a particularly worrisome aspect of space travel and it will require more time and research to determine the very best ways to protect astronauts.

So, Just How Dangerous Is Space Travel Really?

Traveling outside the bounds of planet Earth can have some significant and potentially dangerous effects on the human body. Our excursions to space are only going to increase in duration and frequency as technology advances, so it’s crucial that we continue to develop ways to protect these brave astronauts. If you are a former, current, or aspiring astronaut, the most important thing you can do is create a solid foundation of health.

The steps outlined in this article are a good place to start. And if you’re ready to take it up a notch and design foundational and vibrant health unique to you, head over to my blog and explore my hundreds of articles designed with that in mind. To take it even deeper, you can always sign up for my weekly newsletter by entering your name and email address in the form below.

Now it’s time to hear from you. Were you surprised to learn about the hazards of human space travel? If you’re an astronaut, let us know your favorite health hacks to support your well-being before, during, and after your missions. Leave your questions and thoughts in the comments below! 

References:

1. Red risks for a journey to the red planet: The highest priority human health risks for a mission to Mars | npj Microgravity (nature.com)
2. Hazards to human spaceflight (spaceandbeyondbox.com)
3. NASA – Space Radiation Health Project
4. The hazards of space travel (nih.gov)
5. NASA Research Reveals Biological Clock Effects on Sleep for Astronauts | NASA
6. 5 Hazards of Human Spaceflight | NASA
7. The hazards of space travel (nih.gov)
8. Hazards to human spaceflight (spaceandbeyondbox.com)

Medically Reviewed by Dr. Jill Carnahan, MD