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Short sleep and long sleep don’t appear to damage the body the same way. Fewer than 6 hours was linked to cardiovascular disease, type 2 diabetes, high blood pressure, obesity, kidney disease, and psychiatric conditions, including depression and anxiety. More than 8 hours showed a stronger genetic connection to brain-related conditions like major depressive disorder, bipolar disorder, and schizophrenia, and may often signal that something is already going wrong rather than acting as a direct cause.

Here’s the number that puts everything else in perspective. Short sleepers had a 50% higher hazard of death during the study’s follow-up period. Long sleepers had a 40% higher hazard. People sleeping 6 to 8 hours outlived both groups by a significant margin.

Article says this window can vary by sex but then doesn't address it at all. I'm guessing based on other studies that women need more sleep on average?