Sleep as a vital sign

When I was in medical school, the four vital signs were blood pressure, pulse, breathing rate, and temperature. Over the years, pain level has been added to the list of vital signs by some medical practices and hospitals. Here is an interesting article advocating for assessment of sleep during routine medical visits, much like the way vital signs are automatically assessed with each patient encounter.

The authors note how sleep disorders are under-diagnosed, and how sleep disorders can affect so many other areas of a person's health. Also, many non-sleep disorders affect how a patient sleeps. At the end of the article, the authors pose a question as to how to assess a patient's sleep during a routine visit. Unfortunately, there is no rapid objective measure of sleep quality that can be used during a routine visit, like how we measure blood pressure. So an assessment of sleep is subjective, like the assessment of pain. Many non-sleep physicians already ask questions such as "How are you sleeping?". Perhaps having a patient rate their sleep quality on a scale of 1 to 10, similar to how some clinicians assess pain levels? That would be an interesting research project to do.