The official recommendation for adults aged 18–64 is 7 to 9 hours per night. Adults over 65 may do well on 7 to 8.
Why 7 hours is the floor
Below 7 hours, studies show increased risk of cardiovascular disease, weight gain, and cognitive decline.
Quality matters more than length
Eight hours of fragmented sleep is less restorative than seven uninterrupted hours.
Find your sweet spot
Go to bed at the same time for two weeks without an alarm. Your natural wake time reveals your true need.
Final word
Sleep is the foundation of every other health metric. Pick one habit from this guide and apply it for the next seven nights — small, consistent changes compound quickly.