A study reveals that sleeping more than nine hours per night may pose greater health risks than sleeping too little. While lack of sleep is commonly linked to heart disease, weakened immunity and depression, researchers now find oversleeping connected to even more serious outcomes, including higher mortality and chronic conditions like diabetes and depression.

The research, reflecting global analyses, indicates that adults sleeping over nine hours had a notably increased risk of premature death compared to those maintaining seven to nine hours of rest. The results echo earlier findings showing long-sleepers had a 14–34% higher mortality risk. Additionally, studies highlight oversleeping’s association with stroke, metabolic disorders, obesity and reduced cognitive function—particularly in those with depressive symptoms.

Experts caution the relationship may reflect underlying health issues rather than oversleep itself causing harm. Conditions like sleep apnea, chronic illness or depression might drive longer sleep durations.

Despite oversleep being less discussed, specialists emphasize its significance. Balanced sleep, alongside quality, is key to well-being. They recommend adults aim for 7–9 hours nightly, monitor persistent deviations, and consult a healthcare professional to rule out underlying disorders.