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KIDS: Our World!
EVAN: Ninety Eight, Ninety nine, One hundred. Whew!
I do my best to stay fit.
We all know that exercise is an important part of a healthy lifestyle,
but did you know that exercise is even more
important when youíre training to be an astronaut?
Other than eating and drinking, what do you think
NASA astronauts to stay healthy?
KIDS 1: Hmm...Experiments!
KIDS 2: I know, I know. Is it Moon walking?
EVAN: Exercise! You see floating in space is a lot of fun,
but spending time in space causes changes in the body
that arenít good when the astronaut returns to Earth.
You see on Earth, our bodies work against gravity.
Gravity is the force that pulls you to the ground.
When you stand up, you have to lift the weight of your
body and carry that weight wherever you go. The muscles in your legs,
back, and neck have to work against gravity with every step you take.
Even when you take a rest after playing with your friends,
your muscles are still working against gravity!
Your bones get a workout too.
Your skeleton supports your muscles and protects your insides.
When you stand up, walk, or run around, your bones are carrying your bodyís weight Ė
this kind of work keeps your bones strong.
Gravity gives your heart a workout too.
When you are standing up on Earth, gravity pulls the blood down toward your feet,
so your heart works hard against gravity to pump the
blood up to your brain and to keep the blood moving from
your feet back up to your heart.
But in space all of these things change. You want to find out more?
Letís visit a friend over at NASAís Johnson Space Center.
Dr Kjell Lindgren helps keep our astronauts healthy and fit for travel!
DR. LINDGREN: Weightlessness looks like a lot of fun.
The astronauts are floating their tools and their food is also floating around.
But itís also hard on the body as well. The heart
doesnít have to work as hard because youíre not standing up.
When you stand up on Earth the blood is pulled down by gravity
and the heart and the muscles have to work to keep the
blood moving back up to the heart and up to the brain.
So the heart doesnít have to work as hard in space.
Your bones and your muscles also donít have to work as
hard because youíre not standing up, your not having to work against gravity.
So those can weaken, and so you can lose bone mass
and your muscles can become smaller.
Itís very similar to someone just laying in bed all the time.
Scientists actually use that as a model or a way to
demonstrate the effects of weightlessness.
We have people lay in bed for long periods of time and we
look at how their bones weaken and their muscles
and their hearts weaken as a result. Some of these tests last up to 90 days.
EVAN: In bed for a 90 days! Thatís no fun.
DR. LINDGREN: So we use exercise in space. The astronauts exercise
to help keep their bones healthy and their muscles
healthy and their hearts healthy.
EVAN: Thanks for sharing all this fascinating information with us.
Astronauts can inspire you to make physical fitness a part of your life too.
Iím even more motivated to work out than before.
Come on Globey, Iíll race ya!
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KIDS: Our World!