What happens to human cells in space?

If our cells are impacted by information coming from the environment...what does that entail for cells in space?


Outer space is a harsh, unforgiving environment. The enormous strains space flight puts on human physiology pose a major barrier to exploration of the solar system. Here’s an overview of the ways space can affect astronaut health, and why MitoQ might be a great option for space travelers.

How does space affect the human body?

cardiovascular system

One of the most significant risks to the human body in space? Space radiation. On Earth, we’re shielded from the brunt of radiation by our magnetic field and unique atmosphere composition. In space, cosmic rays from the wider galaxy, solar particles, and particles (including from Earth’s magnetic field itself) all produce significant sources of radiation which can cause long-term health impacts for astronauts. The exact level of risk depends on the length of the astronaut’s mission. Normally, astronauts can only stay at the International Space Station for a maximum of two 6-month periods, mostly due to the health risks that come with longer stays.

The transition to a lower-gravity environment is another major challenge for the human body. Astronauts suffer from significant issues like bone mineral density loss during spaceflight, trouble maintaining blood pressure, profound muscle loss, and other risks including vision problems, compromised immunity, and kidney stones.

Sleep can also be difficult for humans in space, as the body’s internal clock can be completely thrown off without the regular cycles and triggers that help us sleep on Earth. There’s no standard dark-light cycle, lots of artificial light, plus, no gravity means you can’t so much as lay your head on a pillow. As a result, astronauts have fewer hours of shuteye each night, plus their sleep is of a lower quality, accumulating over time to affect their concentration and performance.

Closely linked to all the above is the toll space flight takes on astronauts’ mental health. While being in space can be an incredibly thrilling adventure, the long distance from home, and a sense of fear can lead to psychological stress.

What happens to your immune system when you go into space?

As you may have guessed, extensive research has shown that spaceflight weakens the immune system.

A series of direct and indirect effects of space lead to a lowered immunity in astronauts. Mind-boggling as it sounds, zero gravity leads to changes in the microenvironments of organs themselves, disturbing the process of immune cell production. Weightlessness, space radiation, and other stressors can impact stress hormones in the body, which also feeds into immunity and how the body may react to infections and allergens.

While space is devoid of microbes (at least, no life has been found yet), studies have shown that the microbes which hitch a ride in the spacecraft seem to become even more virulent in space than on Earth as they adapt to weightlessness, meaning they are more likely to infect humans onboard. Even perfectly healthy astronauts can become infected by latent virus reactivation – latent viruses are those which aren’t completely wiped out by immune attack, and are kept in check by immune cells. Being in space appears to reactivate latent viruses as a result of compromised immunity, which means immune cells aren’t activated properly. Pairing compromised immunity with more dangerous pathogens spells potential trouble, particularly for longer missions, and particularly with the looming possibility of commercial flights in space someday.

How do cells react in space?

stem cells

In order to cope with this new strange environment, physiological changes occur that alter the body’s natural homeostatic balance, allowing humans to acclimatize to abnormal conditions as much as possible – it's the same principle behind why a person’s body acclimatizes to being high up in the mountains (and why people can get altitude sickness if they don’t acclimatize properly). Unfortunately, these physiological changes ultimately have some less than desirable side effects.

The landmark NASA Twins Study showed undeniable consequences of space flight, by comparing test results on various health parameters between twins where one sibling was an astronaut, and the other was not. According to this study, there are several key factors that impact humans at the cellular level during spaceflight:

  • Mitochondrial dysregulation
  • Increased oxidative stress
  • Excessive free radicals
  • DNA damage
  • Telomere shortening
  • Variations in microbiomes
  • Epigenetic changes

The radiation in space is thought to lead to imbalances in free radicals and antioxidants in astronauts, resulting in excessive free radicals. As a result, astronauts are extra prone to flow-on effects like oxidative stress (which we’ve talked about before in articles like this one), damage to mitochondria, and the introduction of mutations to their DNA. The human body relies on a rather delicate series of constant checks and balances, ultimately guided by the information passed on by the environment around you. Perhaps it’s no surprise then that changes in space, lead to cellular level changes, which then underpin all of the crazy things happening to human physiology in space travel.

It’s an area of ongoing research – last year, scientists even instigated a high-flying experiment of stem cells in space to see how they grow and observe their responses to zero gravity.

Could MitoQ potentially support cell health during space travel?

MitoQ Pure

If we want to extend spaceflight trips, and maybe even get people on Mars in the next twenty years, we’re going to need ways to help astronauts keep healthy for longer throughout the tough conditions of spaceflight.

Astronauts already have to be careful to maintain their health during space travel. People in space have to remain hydrated, focus on sleep, protect themselves from excess UV radiation, eat a well-balanced diet – with plenty of nutrients like calcium, folate, and vitamin D – and exercise regularly.

Taking dietary antioxidant supplements is already recommended for astronauts because of their increased free radical production in space, paired with lowered antioxidant defenses – an effect which can last for weeks after touching down back on Earth. With the clear link between space flight and oxidative stress, research suggests that targeting oxidative stress may help improve astronaut performance and support their health during spaceflight. Enter MitoQ: a supplement clinically proven to reduce oxidative stress. With a wealth of studies, an excellent safety profile, and unique mitochondria-targeted action, the MitoQ molecule can specifically target the body’s major source of oxidative stress.

So, going on a spaceship anytime soon? It takes a cutting-edge molecule to help with cutting-edge exploration. We'd like to see research-backed antioxidants like MitoQ be the first choice for space travelers and Earth-bound citizens alike.

Learn more about the science behind MitoQ

skin cells and mitochondria

The Heart-Brain Connection

While it may seem like the brain and heart run independently, these two arms of the body are both intricately interwoven with one another. While scientists continue to uncover the depths of their relationship, here's what you need to know about how their line of communication influences your body.

Read more

Mitochondria and cells

5 incredible scientific breakthroughs in 2023

While we've experienced many advancements here at MitoQ in 2023, we can't help but reflect on some of the incredible break-throughs in the wider world of science this year.

Read more