GoKawiilTaxi and ambulance drivers are less likely than workers in almost any other job to die of Alzheimer’s disease. That was the surprising result of a 2024 study examining the death certificates of nearly 9 million people in the U.S.
These findings stopped me in my tracks because those two jobs rely on the same thing as my own work: maps.
I have spent more than two decades staring at maps. Not paper maps on a wall, but digital ones with multiple layers: flood boundaries draped over census blocks, car crash hot spots plotted against road geometry, and satellite readings of rainfall stitched across river basins. Much of my work as a civil and environmental engineer is done through GIS – that is, geographic information systems. Engineers like me hold several spatial relationships in their minds at once, reasoning about where things sit relative to one another across scales ranging from a city block to a whole watershed.
I always assumed that spatial reasoning across map layers was purely professional. But that study on taxi and ambulance drivers made me wonder whether all that mental work might be doing something good to the brain.
Taxi driver brains
Of the 9 million death certificates from January 2020 to December 2022 that researchers examined, taxi and ambulance drivers had the lowest risk of dying from Alzheimer’s disease out of 443 occupations. After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall.
This pattern did not extend to other driving jobs. The researchers concluded that the key to reducing the risk of Alzheimer’s was not driving itself but continuous real-time navigation: the constant work of locating yourself in space, tracking a destination and updating a mental map as conditions change. Drivers whose jobs relied on fixed or predetermined routes, like bus drivers and aircraft pilots, didn’t seem to experience a similar advantage.
Researchers believe the association between navigation-heavy work and lower Alzheimer’s risk centers on the hippocampus, a part of the brain that governs memory and spatial navigation. It’s one of the first brain regions that Alzheimer’s damages: Problems with spatial navigation and orientation are among the earliest signs of the disease, sometimes surfacing before obvious memory loss.
In one landmark 2000 study, neuroscientists compared the brains of licensed London taxi drivers with those of people who did not drive cabs. Their findings provided the first evidence via structural imaging that regions of the adult brain can measurably change under sustained navigational demand. To earn a license, London cabbies must memorize more than 25,000 streets within a 6-mile radius of Charing Cross, a challenge known as “The Knowledge” that takes three to four years.
The researchers found that London taxi drivers had measurably more gray matter in the posterior hippocampus, a brain area tied to storing large-scale spatial maps. That volume tracked with experience: The longer someone had driven, the larger that part of the brain. The change was built through practice, not inherited. While people who are good at navigation might gravitate to this kind of job, the job itself does have an impact on the brain.
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