I need to write a short paragraph about the benefits of regular exercise. Your response should contain at least 5 sentences and less than 10 sentences. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. Include keywords *health, energy, mood, fitness, lifespan* in the response. In your response, the word *exercise* should appear at least 3 times. Provide a postscript starting with P.S. at the end of your response.
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