wind down/unwind Hi, Could you please tell me whether I can use "wind down" in formal context e.g an academic essay? Because I learned that phrasal verbs are generally 'informal'. Here are some examples taken on the Internet: - This can lead to serious physical and mental health issues, which is why it's extremely important to wind down, both body and mind. - It's proven that the blue light from phones and tablets wakes up the brain making it difficult to wind down and fall asleep. I think 'unwind' is better in such situations. Thank you very much.