There have been a total of 536 people in space since Russian astronaut Yuri Gagarin became the first human to leave planet Earth in 1961. 12 people have walked on the moon, and the days that astronauts have spent in outer space add up to a cumulative total of more than 77 years. That’s 22 years longer than the amount of time that humans have been exploring space for.
Space travel is reserved for the highest level of the elite. The elite of the elite. Very few people in this world can accurately describe the experience of what it’s like to be in space, but these few descriptions are undoubtedly remarkable and mind-blowing for us mere mortals down here on Earth.
The zero gravity conditions of outer space cause many changes to the human body. Astronauts must go through rigorous physical and mental training before their missions, as well as making sure to keep up their health during and after the flight. Perhaps in the future space travel will be a common practice, and we’ll all be taking vacations to Mars and weekend trips to the moon. If that is to be the case, you may want to prepare in advance by reading up on these five crazy facts about what exactly happens to you in outer space.
1. Your Body Gets Weaker
The skeletal-muscular system of your body works to enable you to sit, stand, walk, and move. This range of motion, while you’re on Earth, is affected by gravity. Your muscles have plasticity, meaning that they are able to adapt to various conditions and different loads. However, when you are in space there is no gravity, so your skeletal muscles are serving little purpose because there is no load being placed on them. This causes the same effect as if you were to all of a sudden completely stop using your muscles- your muscles atrophy (lose mass) and your body becomes significantly weakened.
Research have found that astronauts have an average decrease in strength between 8% and 17% after space flights, even though they are required to follow strict exercise routines. The scientists’ data estimates that about 30% of muscle strength is lost after 110-237 days in sub gravity conditions.
2. Your Heart Is Affected
Space travel also affects the cardiovascular system, because it too is influenced by the Earth’s gravitational pull. Your heart, arteries, and veins are constantly working to pump blood either towards or away from the heart; for example, veins in the legs are working against gravity to return your blood back to your heart.
In the absence of gravity, the cardiovascular system undergoes dramatic changes. The heart, like the other muscles, decreases in mass. This in turn causes a reduction in blood volume. In space, your heart rate as well as your blood pressure is much lower. When there is no gravity, more blood will stay in your legs because less blood will be able to be taken back to the heart, so there will be less total blood volume for your heart to pump throughout your body.
3. Your Fitness Is Impaired
With your muscles growing weaker and weaker the longer you’re in space and your heart struggling to adjust to the changes, it should come as no surprise that your overall fitness becomes significantly worse in outer space.
Aerobic capacity, or the highest amount of oxygen that your body can use while exercising, has been measured in astronauts before and after their flights. Not surprisingly, researches have discovered reduced aerobic fitness after space travel.
For example, after only 9-14 days of spaceflight, scientists have found that aerobic capacity was decreased between 20% and 25%. However, they have also discovered that if the space travel extends for longer periods of time (multiple months), the body will compensate for the initial drop in aerobic fitness and the statistics begin to improve, although they never fully go back to the levels that they were at before space travel.
4. Your Bone Mass Drops
In addition to maintaining muscle mass and heart health, gravity is needed to maintain proper bone structure. Bet you had no idea how much of a role gravity plays in keeping you a functional human being, right?
In space, the lack of gravity takes a significant toll on your bones. There are two different types of cells that are responsible for normal bone remodeling processes; osteoblasts (build bone) and osteoclasts (absorb bone). In zero gravity conditions, the balance of osteoblasts building bone and osteoclasts breaking down bone is altered, leading to a decrease in bone density. According to scientific findings, 3.5% of bone mass is lost after 16-28 weeks in space
5. There’s A Toll On Your Immune System
As if all of these strains on your body and physical condition weren’t enough, being in space also has an affect on your immune system. Zero gravity, radiation, stress, and isolation all contribute to a weakened immune system. There is also no lack of bacteria and microbes in the environment of the spacecraft, which can affect the immune response and lead to potential infections. Still feel like traveling in space?