What do you do when you feel unhappy? Do you listen to music? Do you talk to a friend?
Maybe next time you feel sad, you should try going outside if it is sunny. Doctors know that how much sunlight we get can change how we feel. Scientists learned this by interviewing people who live in different parts of the world. In the far north, in Alaska or Finland, for example, the days are very short in the winter. People living in these places say that they often feel unhappy in the winter. In the south, where there are more daylight hours, fewer people say they are unhappy in the winter. The reason is the amount (数量) of sunlight these people get each day. Sunlight changes the chemicals (化学物) in our bodies, and these chemicals can change the way we feel. A couple of hours of strong sunlight or light from a special lamp can help your body make the chemicals that make us feel happy.
Another way to feel happier is to get some exercise. Just like sunlight, regular exercise helps our bodies make certain chemicals, which make us feel happier. In addition, exercise helps people sleep better and lack of sleep often makes people feel unhappy. Exercise also helps you get rid of stress. When you are angry or upset about something, exercise is a good way to get those bad feelings out of you.
