bike radar article wrote:The reason why exercising helps bad air to hurt you is simple: when you’re exercising, you breathe in more of it. Up to 15 times more. “As well as sucking in a signiﬁcantly greater volume, you’re also sucking it in much deeper, so it has a greater chance of getting absorbed,” says Mandy Dryer, a respiratory physiotherapist at the Manchester Royal Inﬁrmary.
globe and mail article wrote:At the lower exercise intensity, diesel fumes increased the amount of energy needed to maintain pace and forced the subjects to breathe more heavily. The total volume of air inhaled per minute increased from 39.9 litres in clean air to 44.5 litres with diesel added. But at the higher exercise intensity, which corresponded to a moderate but sustainable effort, there were no differences in respiratory or metabolic response between the clean air and the dirty air.
so pootling in pollution can make your heart work harder than in clean air... but going all out may not.... or so the findings of this one study are suggesting. As they stated - complex, not completely understood. Also not really what you'd expect - you'd think harder effort in pollution, similar to easier effort, would up the energy required even more.