Exercise generally lowers dementia risk – hooray! But there are nuances – exercise performed in the context of work does not seem to lower dementia risk. This suggests to me either that stress plays a huge role, or that people with active jobs are actually doing more than the optimal amount of exercise. Maybe both. Another thing that surprised me here is that active commutes are not shown in the data to reduce dementia risk. That’s a shame, because I want people who shift from a car commute to an active walking or biking commute to be healthier. Maybe stress plays a big role here too – caused by real and perceived physical safety risks, noise pollution, and air pollution. If so, these are things we can try to mitigate through better design of our urban infrastructure.