How do Astronauts Exercise in Space?
How do Astronauts exercise in Space?
Living in the International Space Station presents numerous challenges to the human body due to the harsh environment. Microgravity, for example, causes several health and physical changes that astronauts must counteract through exercise and other activities. However, some elements of the space environment are unavoidable and can't be mitigated.
Our bodies are not designed for space; they have evolved over thousands of years to function optimally under Earth's gravity and atmospheric conditions. In low Earth orbit, these fundamental elements are absent, and the body's systems must adapt to the new environment.
One of the most significant challenges for astronauts in space is the loss of bone and muscle mass. On Earth, these systems are constantly exercised by simply standing and moving against gravity. However, in the absence of gravity, bones lose mineral density and muscles can weaken. To combat this issue, astronauts strive to prevent these changes as much as possible. Bob Tweedy, the countermeasures systems instructor at NASA's Johnson Space Center, explains that astronauts on the space station exercise for 2.5 hours per day, six out of seven days per week, in order to minimize the effects of bone and muscle loss.
Exercising on the ISS (International Space Station)
To help astronauts prevent bone and muscle loss, the International Space Station is equipped with three specially designed exercise machines: a bicycle, a treadmill, and a weightlifting machine called ARED (Advanced Resistive Exercise Device). Since regular gym equipment would be ineffective in microgravity, these machines are customized for use in space. For example, lifting weights would be pointless since the dumbbells wouldn't have any weight. Therefore, the ARED machine utilizes two canisters that create small vacuums that astronauts can pull against with a long bar, allowing them to perform exercises such as squats, bench presses, deadlifts, and more.
Similarly to the weightlifting machine, the treadmill on the International Space Station is not your typical running machine. Astronauts must be strapped into it using a harness and bungee cords, otherwise they would simply float away and not receive a proper workout. In addition, there is a stationary bicycle available for strengthening leg muscles, but it lacks a seat since gravity does not hold the rider down. Instead, astronauts hold onto handles and lean against a back pad to maintain their position. Practicing with these machines on Earth cannot fully prepare astronauts for their use in space since the absence of gravity is ever-present.
However, astronauts must also contend with a phenomenon called fluid shift while in space. Without gravity pulling bodily fluids downward, they shift upward into the chest and head, causing circulatory issues and even changes in vision. Although most of these changes are temporary, they typically subside once the astronauts return to Earth.
Ratiation and Astronauts Health
Living in space also exposes astronauts to harmful elements, primarily space radiation, which can cause damage to the body over time. Energetic particles from the Sun and beyond our solar system can penetrate materials and skin, posing a risk to the astronauts' health. However, astronauts on the ISS are shielded from a substantial amount of space radiation by Earth's magnetic field, which acts as a protective barrier around our planet. Nonetheless, NASA monitors their radiation exposure over the course of their careers, and they have lifetime limits to ensure that they are not exposed to too much radiation.
As astronauts venture deeper into space, the risk of space radiation becomes an even greater concern since they will be outside the protective barrier of Earth's magnetic field. While astronauts on the International Space Station are shielded from a considerable amount of space radiation, NASA implements lifetime limits to ensure they are not exposed to excessive levels. Peter Guida, the liaison biologist at NASA’s Space Radiation Lab, explains that astronauts on the space station are exposed to different amounts and types of radiation compared to those on deep space missions. NASA carefully measures these differences to ensure the safety of astronauts.
To study the effects of space radiation, NASA has set up a specialized lab at the Brookhaven National Laboratory in Long Island. Here, scientists like Guida use a particle accelerator to generate simulated space radiation and observe its impact on biological samples. Instead of bringing the samples into the radiation, the radiation is brought down to the samples. This research is essential for developing improved shielding technologies that can effectively mitigate radiation in space, enabling astronauts to venture further into space than ever before.
