1 sleep killer isn't social media or an uncomfortable mattress — it's rumination . As a psychologist who studies sleep for a living , I've worked with hundreds of patients to improve their sleep through cognitive behavioral therapy. Your attention is drawn back, again and again, to this thing that didn't go well or to a regret. Here are two ways to stop ruminating at night — and they only take 15 minutes to do:1. A licensed clinical psychologist, he has helped hundreds of patients improve their sleep using cognitive behavioral therapy for insomnia.

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