Information from Mayoclinic
When you have depression or anxiety, exercise often seems like the last thing you want to do. But once you get motivated, exercise can make a big difference.
Exercise helps prevent and improve a number of health problems, including high blood pressure, diabetes and arthritis. Research on depression, anxiety and exercise shows that the psychological and physical benefits of exercise can also help improve mood and reduce anxiety.
The positive effects exercise has on conditions such as anxiety and depression have been studied since the 1980s. The euphoria that follows acute exercise, known as 'runner's high', was discovered by Kenneth Cooper of the Cooper Institute, who cited the case of a man 'who was so despondent, he wanted to die. Because his heart was weak, he thought the best way to commit suicide without embarrassing his family was to run around the block as fast as he could until he killed himself.