Both on Earth and in space, headaches affect people’s daily lives. In the case of the astronauts in the International Space Station, the ailment is much more uncomfortable: they cannot rest as they would on the planet, lying down, without noise and in the dark.
In addition, each crew member on a mission must meet certain daily objectives. The pressure is much higher.
According to Robert Frost, NASA’s director of flight operations, about 70% of astronauts on long-duration missions aboard the ISS report headaches.
The number is reduced if the mission is shorter: 69% of male astronauts and 55% of women. Unfortunately the data is from 2017, there are no more recent ones.
Possible reasons for the headache in space
What causes the headache in space? Frost indicates that microgravity is the main reason. Fluids, instead of collecting in the lower part of the body (as they do when on Earth), are distributed evenly throughout the body.
Thus, the crew members of the station have more liquid floating in their heads than people on the planet.
“This can cause congestion and pressure, which would lead to a headache,” says Frost, quoted by Forbes. “That pressure can also affect the shape of the eyes, changing the view of astronauts, which can lead to headaches.”
The carbon dioxide factor
NASA, in a 2015 paper, explained that the atmosphere of a spacecraft tends to have a higher concentration of carbon dioxide than the air we breathe on our planet.
For every mmHg increase in the partial pressure of carbon dioxide, the probability of experiencing headaches doubles.
Other reasons are the noise on the International Space Station and the stress in space, as well as the distance from loved ones.
Astronauts must resort to painkillers (the normal ones consumed on Earth, but in higher amounts) and a balanced diet, seeking to reduce the chances of suffering from headaches.