From VOA Learning English, this is the Health & Lifestyle report.Many diseases and medical conditions are caused by things out of our control.Yet experts say you can control and even prevent many of the risk factors that increase your chances of dying.Experts note that an unhealthy lifestyle can put you at great risk of heart disease and stroke.Poor diet, having too much body fat and a lack of physical exercise all increase your risk of heart disease ―so can using tobacco products and drinking too much alcohol.So doctors urge us to eat healthy foods, get exercise, stop smoking and limit our alcohol intake.But there is something else you can do. And it is free and easy. Smile!Anand Chockalingam is a heart disease specialist at University of Missouri Health Care in Columbia, Missouri.He advises his patients to smile."When we smile, the brain wiring gets altered. The chemicals that are released are more positive."