Stuck in traffic? Keep your cool. A study from Taiwan suggests that running your car’s air conditioner can help your heart. When people kept the air on during their two-hour commute, their heart rate variability, a measure of cardiovascular health, was as much as 32% better than that of people who rolled their windows down instead. Study author Dr Kai- Jen Chuang, says aircon filters out exhaust particles, pollutants that can cause a cascade of internal inflammation. Over time, this inflammation can disrupt your heart’s electrical signals.