Space Flights Can Lead to Tension Headaches, Migraine in Healthy Astronauts

Most astronauts experience headaches during space flights, even if they do not have a history of recurrent headache while on Earth, according to the findings of a prospective study published in Neurology.

Recurrent headache can occur both early and later in space missions, with differing episodes consistent with both tension-type headache and migraine. Causes and best practices for treatment remain poorly understood. For the study, researchers sought to determine the time course of headache during space missions, identify possible mechanisms, and determine what treatments are effective during space flight.

The researchers collected data on 24 astronauts (mean age, 47; 96% men) from Europe, Japan, and the US, who had participated in expeditions between November, 2011, and June, 2018, on the International Space Station. The cohort provided baseline data on their preflight headache history. The astronauts then completed questionnaires each day for the 1st week of their missions, and weekly questionnaires thereafter, through completion of the missions. These data were compared with retrospective questionnaire data, for flights that occurred between 2006 and 2016, from a separate cohort of European and American astronauts.

In the study, sufficient data were available for 189 headache episodes, in 22 of the 24 astronauts interviewed. A total of 90% of all episodes were consistent with tension-type headaches, with the remainder classified as migraine or probable migraine. Of the headaches, 64% were of mild intensity; 60% of episodes lasted 4 hours or less.

Accompanying symptoms were most likely to be nasal congestion (36% of episodes during any period) or loss of sleep (19%). During episodes in the week 1, facial edema (41%) and nausea (18%) were also relatively common. The second day of flight was the most common day to experience a headache (57% of episodes, P =.02).

Headaches occurred just as often later in flight as during week 1, though they tended to be briefer. However, migraine tended to occur earlier more often than later during flights: compared with only 5% of episodes in later weeks, 24% of week 1 episodes were consistent with migraine. Likewise, nasal congestion (P =.004), nausea (P =.05), and vomiting (P =.005) happened more often during week 1 than in later weeks. No headaches were reported among the cohort 3 months after returning to Earth.

Antiheadache medication was used, typically with good result, to treat 56% of episodes — usually a nonsteroidal anti-inflammatory (NSAID) medication or acetaminophen. Other medications, coffee, sleep, hydration, or exercise were used as remedies in smaller proportions of episodes.

Headaches were not found to be attributable to onboard environmental factors: mean CO₂ and O₂ levels, humidity, temperature, and ambient air pressure did not covary with headache occurrences.

Headache characteristics and timing captured in the retrospective study were similar to those in the prospective study.

“Further research is needed to unravel the underlying mechanisms of space headache and translate them to headaches occurring on the Earth. In addition, more effective therapies need to be developed to combat space headaches because for many astronauts, this [is] a major recurring disabling problem during space flights,” the researchers concluded.