Exercise Lessens Anxiety (PsychCentral):
Although we often think of it negatively, anxiety is a normal emotion, Abramowitz said. It evolved in our ancestors as a response to danger, such as a nearby predator. When you perceive a threat, you begin sweating, your heart rate increases and your breathing accelerates — the “fight or flight” response.
Of course, many modern dangers – such as a bad grade or an unsatisfactory job interview – can’t be thwarted by fighting or fleeing. In those cases, you may be left with only the unpleasant effects of anxiety, such as sweaty palms and a pounding heart.
Exercise can help you manage anxiety by distracting you from your worries and giving you a feeling of accomplishment, Abramowitz said. It also causes your body to release endorphins, pain-relieving chemicals that suffuse you with feelings of well-being.