Many individuals feel unwell during or after air travel. This common sensation arises from physiological responses to the unique cabin environment and individual susceptibility. A combination of factors contributes to how the body reacts to altered conditions inside the aircraft.
How Cabin Pressure Affects the Body
Airplane cabins are pressurized, but not to the same level as sea level, typically maintaining an equivalent altitude of 6,000 to 8,000 feet above sea level. This reduced atmospheric pressure causes gases within the body to expand. Air trapped in cavities like the middle ear, sinuses, and gastrointestinal tract can increase in volume, leading to discomfort.
This expansion often results in barotrauma, causing fullness or pain in the ears. The Eustachian tubes, which connect the middle ear to the back of the nose, are responsible for equalizing pressure, but they can struggle to keep up with rapid changes during ascent and descent. Similar pressure imbalances can affect the sinuses, causing facial pain or congestion.
Additionally, the expansion of gases in the digestive system can lead to bloating, abdominal discomfort, and increased flatulence. The lower air pressure also means less oxygen is available, which can lead to fatigue or shortness of breath for some individuals.
The Role of Motion Sickness
Motion sickness, a common ailment during air travel, arises from a sensory conflict within the brain. The vestibular system in the inner ear, which helps maintain balance and detect motion, sends signals to the brain about movement. However, when visual cues from inside the cabin suggest stillness while the inner ear senses motion, particularly during turbulence, these conflicting messages can confuse the brain.
This discrepancy can trigger symptoms such as nausea, dizziness, and vomiting. The fluid in the inner ear shifts with aircraft movements, sending signals that may not align with visual cues. This mismatch can lead the brain to trigger symptoms like nausea and vomiting. The physical sensations of turbulence, even if subtle, can intensify this sensory conflict, making some individuals more susceptible to airsickness.
Cabin Environment Factors
Airplane cabins are notably dry, with humidity levels often dropping to between 5% and 20%. This low humidity causes moisture loss, leading to dry eyes, throat, and skin, and a sensation of thirst.
Regarding air quality, air in commercial aircraft cabins is recirculated and mixed with fresh air. Modern aircraft utilize High-Efficiency Particulate Air (HEPA) filters, which are effective at removing over 99.9% of microscopic particles, including bacteria and viruses, from the recirculated air. Despite these filtration systems, the close proximity of passengers increases the likelihood of exposure to airborne germs, especially from those who are coughing or sneezing.
Surfaces like tray tables and seatbelt buckles can also harbor germs, contributing to illness transmission through direct contact. The confined space and interaction with many individuals remain considerations for health.
Personal Habits and Travel Sickness
A traveler’s physical state before and during a flight influences their susceptibility to feeling unwell. Maintaining adequate hydration is important, as dehydration, exacerbated by the low cabin humidity, can worsen feelings of fatigue and malaise. Consuming light, easily digestible meals before and during the flight can help mitigate gastrointestinal discomfort, while heavy, greasy, or carbonated foods may increase bloating and nausea.
Sleep deprivation can lower resilience to flying stressors, increasing susceptibility to motion sickness and discomfort. Pre-existing stress or anxiety about flying can also heighten the body’s sensitivity to cabin changes and sensory conflicts. These personal factors combine with the unique conditions of air travel.