Hey, everyone.
Today we want to talk about a recent study on the bone health of
astronauts that found that six months in
space can lead to a decade worth of long term bone loss.
NASA defines an astronaut as a person
who is trained, equipped and deployed by
a human spaceflight program to serve as
the commander or as a crew member aboard a spacecraft.
Astronauts go to space for varying amounts of time
however, the typical space mission lasts
about six months and some astronauts have stayed in space for over a year.
A common destination for astronauts is the ISS or the International Space Station.
On the ISS, astronauts experience microgravity where they do not feel
the effects of gravity and they are able to flow freely.
The human body has evolved to deal
with the force of gravity pulling us down such as by making our skeletons rigid so
the lack of gravity in space could impact our body significantly.
As space agencies preparing to send astronauts to Mars, a trip estimated
to take nine months each ways, it is important for agencies to understand
the impacts that space could have on the body.
On Earth, our bones experience a constant
load on them due to the force of gravity constantly pulling us down
and to support us, our bones have
to maintain a certain density.
Bones are made up of calcium and a protein
called collagen and in order to maintain optimal density our bodies have two
different cells called osteoblasts and osteoclasts.
Osteoblasts add collagen to our bones
and increase our bone density and can be activated in many ways.
A primary response that activates these
osteoblasts includes sensing a low bone density in our bodies.
Osteoblasts constantly survey their area
to ensure that our bones are strong enough to support us.
But if they sense a decrease in density
osteoblasts put down more collagen in order to support us.
Osteoclasts do the opposite of osteoblasts.
Osteoclasts are bone breakers and they
work to remove calcium and collagen from our bones
when our body says we need more calcium in our blood. Like tug of
war they work opposite to one another.
These two types of cells,
osteoblasts and osteoclasts, are constantly adding and removing collagen
from our bones to maintain an optimal
level of bone density throughout all the bones in our bodies.
In space, the bone density that our.
Osteoblasts and osteoclasts maintain changes.
The load that our bones have to support is less in space because of the lack
of gravity so less of our osteoblast become activated.
This means that while our osteoclasts continue to break down our bones, less
of our osteoblasts are adding collagen back to our bones.
This results in bone density decreasing
when astronauts go to space as the balance
between the two types of cells has changed.
So we know that space can affect someone's
bone density but is there anything that we can do to avoid this issue?
The answer is actually yes. According to research,
some things that may aid to reduce the amount of bone loss are exercise
and resistance training before boarding the ship and while on the ship,
creating a diet that includes higher amounts of vitamin D and calcium,
as well as taking some medications that help regulate bone growth and loss.
Research suggests that inflate resistance training and exercise should be increased
to three to six times more than what was being done while on land.
This amount of activity in space may be
sufficient for some astronauts to maintain bone structure and strength.
When astronauts are on long flights, they will experience a change in their
normal diet and will have low sunlight exposure.
The lack of sunlight exposure may result in a decrease in vitamin D in the body,
a nutrient that helps calcium to be absorbed.
Calcium is a key player in growing and maintaining bones,
and without it being absorbed properly, the bones of astronauts may lose density.
To overcome this issue, astronauts can take calcium and vitamin D
supplements or try to consume foods that are rich in these nutrients.
Astronauts could also look into taking medications that increase the amount
of cells that create bones which are osteoblasts or decrease
the action of the cells that break
down bones which are osteoclasts.
The goal of these medications is to reduce the amount of bone being lost so
that the astronauts can maintain strength and stay healthy.
It is important to remember that each and every astronaut has a different body
and what works for some may not work for others.
More research should also be done in order to evaluate how effective these solutions
may be. So what about beyond six months, say two years, the time it takes to go to Mars.
One study did show that astronauts who had been in space longer than six months
experienced permanent bone loss in their shinbones equal to a decade of aging.
However, the research is limited, and there are not many studies in this area.
We would expect that the effects would
simply be worse than what they are for trips under six months,
but it's hard to know for sure what the exact consequences would be.
Thank you for watching.
We hope that our video helped you learn something new about space and its
effects on the bone health of astronauts and hopefully inspires you to learn more.