Interesting study. Just as a slight criticism of your wording, although I don't think this applies to the study- a lot of deaths from heart disease are actually

Interesting study. Just as a slight criticism of your wording, although I don't think this applies to the study- a lot of deaths from heart disease are actually caused by air pollution. Inhalation of particulate matter is implicated in tens of thousands of deaths a year. Even though exercise outweighs inhalation of fumes, air pollution is a serious issue, and many lives could be saved by its reduction. Hopefully that will be an extra benefit of electric and hybrid cars in cities.