An eye-opening new film explores the connection between stress and the continuing fall in US life expectancy.'By the time you finish this article, your brain will have changed. Something you read or something that happens while you’re trying to focus on these words will go on to have an impact on your day.If that event happens to be stressful – maybe you are interrupted by loud colleagues or a loved one calls with bad news – it can trigger a series of more stressful events such as choosing something unhealthy to eat or being unintentionally rude to a friend or co-worker.That chain reaction, if repeated, takes a toll on your overall health and wellness. Stress has been shown to be an aggravating factor in, among other conditions, heart disease, diabetes and mental health problems. That might explain why US life expectancy has fallen three years in a row.'