Describe the benefits of regular physical exercise, ensuring your response has at least 3 paragraphs. Each paragraph should be separated by a markdown divider: ***. Highlight at least 2 sections in your answer with markdown, i.e., *highlighted section*. Your entire response should be in English, and in all lowercase letters. no capital letters are allowed. include keywords *health, fitness, energy, risk, disease, mood, stress, sleep, mental, physical*.
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