Exercise is one of the best ways to help improve your mood, sleep, and overall health. But now scientists have found that exercise can also produce a natural high! They found that blood flow patterns in the brain are dramatically altered after a workout. These changes in blood flow can cause different neurotransmitters to be released into the brain, which leads to feelings of happiness and increased energy. Plus, exercise helps increase the production of BDNF, which allows you to feel great. (source)