It’s the announcement no passenger wants to hear: “Is there a doctor on board?” A major study suggests it happens far more often than most travelers realize, and sometimes it ends in tragedy.
Nearly five billion people fly every year. Most give little thought to what would happen if they, or the person in the next seat, fell seriously ill somewhere over the ocean.
According to researchers at Duke Health, it is worth thinking about.
The Largest Study of Its Kind
A team led by Duke Health analyzed more than 77,000 in-flight medical events reported to MedAire, an aviation and maritime health and safety company that runs an airline medical support center and partnered on the research. The findings were published in JAMA Network Open in September 2025.
The study covered 84 airlines across six continents and more than 3.1 billion passenger boardings between January 2022 and December 2023.
Dr. Alexandre Rotta of the Duke University School of Medicine, the study’s senior author, called it “the largest and most comprehensive study of in-flight medical emergencies ever conducted.”
How Often Things Go Wrong
Roughly one in every 212 flights involved a medical emergency. For anyone who flies several times a year, that is not a remote possibility.
Most of the incidents were minor. But about 8 percent of the passengers affected were taken to a hospital after landing. That works out to thousands of travelers whose trip ended in an emergency room rather than at a hotel or a family reunion.
In 1.7 percent of cases, the situation was serious enough to divert the flight. Hundreds of the events either ended in death or forced the plane to land somewhere else.
The Most Frightening Finding
Cardiac arrest occurred in 293 cases. The researchers found that survival rates in the air were far lower than on land.
Why the cabin is so unforgiving. Rotta described practicing medicine in the air as humbling. There is limited equipment, no laboratory tests and no backup team. Even a minor problem can turn into a major challenge at 35,000 feet.
His point was blunt: airplanes are not hospitals and should not be expected to work like them.
What Forces a Plane to Land
The most common reasons for a diversion were suspected strokes, seizures, chest pain and altered mental status, meaning sudden confusion or disorientation.
These are conditions where every minute counts. Over open water or remote terrain, the nearest suitable airport may be hours away.
Who Steps In When It Happens
Medical volunteers, most often physicians traveling as passengers, helped in nearly one-third of emergencies.
Flights where a volunteer stepped in were more likely to be diverted. The researchers believe this is because volunteers tended to be called to the more serious cases, not because their involvement caused the diversion.
That means that on two-thirds of flights where someone falls ill, there may be no qualified passenger available to help. The crew and whatever guidance they can get from the ground are all that stand between a sick passenger and disaster.
Not Every Airline Has Backup on the Ground
There is some reassurance. Rotta noted that US regulations require airlines to carry defibrillators and basic medical kits, and that carriers are generally well prepared.
The gap lies elsewhere. Not every airline partners with a ground-based medical support center, which connects crews with doctors in real time. Rotta believes every airline should. When a life is at risk, he said, expert advice from the ground can be decisive.
What This Means for Travelers Over 50
The authors say the findings could shape airline policies, improve crew training and help passengers with chronic conditions prepare before they fly.
For travelers with heart conditions, diabetes, a history of stroke or other ongoing health concerns, preparation matters. Talk to your doctor before a long-haul trip. Keep your medications in your carry-on rather than your checked bag. Carry a written list of your conditions and prescriptions, so that if something goes wrong, whoever helps you knows exactly what they are dealing with.
A flight is long enough for a medical problem to become serious, and the nearest hospital can be a long way off.
Source: Duke Health, “New Study Reveals the Frequency of In-Flight Medical Emergencies”
Amanda O’Brien is the creator and editor of The Boutique Adventurer. She has visited 80 countries and is a member of the British Guild of Travel Writers as well as the IFTWTA. She is passionate about wine had has just completed Level 3 of the WSET. Born in Australia, she lives in London.