Space travel in zero gravity poses unique challenges to the human body, with one notable issue being the onset of headaches among astronauts. A recent study published on March 13, 2024, in Neurology®, the journal of the American Academy of Neurology, reveals that even astronauts with no prior history of headaches can experience migraines or tension-type headaches during extended space flights lasting more than 10 days.
According to Dr. W. P. J. van Oosterhout from Leiden University Medical Center in the Netherlands, the changes in gravitational forces encountered during space travel disrupt multiple bodily systems, including the brain. The vestibular system, responsible for balance and posture, must adapt to the mismatch between expected sensory inputs and the signals received in a zero-gravity environment. This adaptation often triggers space motion sickness in the initial week of space flight, with headaches being the most commonly reported symptom. The study further indicates that such headaches persist beyond the initial phase and may be linked to increased intracranial pressure.
The research analyzed data from 24 astronauts affiliated with the European Space Agency (ESA), NASA, and the Japan Aerospace Exploration Agency (JAXA), who participated in International Space Station missions lasting up to 26 weeks between November 2011 and June 2018. Before the study, only three astronauts had experienced headaches interfering with daily life within the past year, and none had a history of recurrent headaches or migraines. Despite this, 22 out of the 24 participants reported at least one headache episode during a cumulative 3,596 days in space.
Astronauts maintained detailed health records and completed questionnaires about their headache history before and during their missions. Daily questionnaires were required for the first seven days of space flight, followed by weekly submissions. Over the course of the study, a total of 378 headaches were documented, with a staggering 92% of astronauts experiencing headaches in flight, compared to just 38% prior to the mission.
The findings highlighted a predominance of tension-type headaches, accounting for 90% of reported cases, while migraines or probable migraines made up the remaining 10%. Notably, headaches were more intense and frequently migraine-like during the first week of space travel. During this initial period, 21 astronauts reported experiencing 51 headaches, 39 of which were classified as tension-type and 12 as migraine-like. Encouragingly, no astronauts reported headaches within three months of returning to Earth.
The study underscores the need for deeper investigation into the underlying causes of space headaches and the development of effective therapies to address this issue. As noted by Van Oosterhout, these findings may not only benefit astronauts but also enhance understanding of headaches experienced on Earth. However, the research does not establish a direct causative link between space travel and headaches, highlighting the need for further exploration.
A limitation of the study is its reliance on self-reported data, which may be subject to recall inaccuracies. Nevertheless, the findings provide critical insights into an often-overlooked health challenge in space exploration.
This study was supported by the Netherlands Organization for Scientific Research.
