Taxi drivers rarely die of Alzheimer's. How complex mental maps and spatial reasoning protect your brain

A 2024 study found that taxi and ambulance drivers are less likely to die of Alzheimer's disease compared to workers in almost any other occupation. This surprising result caught the attention of a reporter who spends more than two decades analyzing maps digitally. The reporter, who works in civil and environmental engineering, noted that engineers like herself constantly work with spatial relationships in their minds, reasoning about the positioning of various elements across different scales.

The researchers examined 9 million death certificates from January 2020 to December 2022 and found that roughly 1 in 100 taxi and ambulance drivers died of Alzheimer's disease, compared to 1 in 60 people overall. This association was not seen in other driving jobs like bus drivers and aircraft pilots, who follow fixed or predetermined routes.

The researchers believe that the lower risk of Alzheimer's among taxi and ambulance drivers is due to continuous real-time navigation, which involves locating oneself in space, tracking a destination, and updating a mental map as conditions change. This constant mental work is thought to engage the hippocampus, a brain region that governs memory and spatial navigation.

The hippocampus is one of the first areas affected by Alzheimer's disease, as problems with spatial navigation and orientation are early signs of the condition.

In a landmark 2000 study, neuroscientists found that licensed London taxi drivers, who must memorize more than 25,000 streets within a small area, had more gray matter in the posterior hippocampus compared to non-taxi drivers. The amount of gray matter in this region correlated with the number of years the drivers had been working. This finding was built through practice, not inherited traits.

The reporter concluded that work that intensively exercises the hippocampus may reshape it and protect against Alzheimer's disease. While the studies focus on where people live and their environment, the reporter suggested that spatial reasoning through a screen may also engage the hippocampus in the same way as real-life city navigation.

The implications of this research could reach beyond mapmakers and cab drivers, as studies have repeatedly found a link between mentally complex occupations and delayed cognitive decline and lower dementia risk.