This is pretty strange, even the article text does not back up the headline.

Dr Raha West, lead author and clinical research fellow at the department of surgery and cancer at Imperial College London, said: “While understanding and working with your natural sleep tendencies is essential, it’s equally important to remember to get just enough sleep, not too long or too short. This is crucial for keeping your brain healthy and functioning at its best.”

The study is not linked and the lead and co lead basically say, "get enough sleep", then other scientists not involved in the study say there are many “important limitations” to the study.

Hey guardian editors, be better