For some people in some situations, the following may work.
Think through the matter that worries you untill you can conclude that there is actually no need to worry. Once you trully realize that and believe your conclusion, you then realize that you are therefore not worried, since you know and believe that there is no reason to be worried. Although your heart is still heavy or racing, that is a physical issue. You can do something to calm your body until it catches up with the news.