Sleep is important for many reasons – but experts have warned that too much can be bad for your brain.
Official NHS guidance states that most adults need between six and nine hours of sleep every night.
Recent studies have however shown that this might not be the case, with some adults needing as little as four hours of sleep to wake up feeling refreshed.
Research from experts in Washington, US, found that having too much sleep could interfere with your cognitive function.
The experts found that people who slept less than 4.5 hours a night, and those who slept more than 6.5 hours each night had a greater risk of cognitive decline over time.
The researchers suggest that for adults, sleeping between 4.5 and 6.5 hours a night is ideal.