Reader Sarah Ho asked if the recommended seven to eight hours of sleep for adults needed to be a continuous period of time at night or can it include short naps while commuting on the MRT or bus.
Senior health correspondent Salma Khalik answered.
The simple answer is "No".
The recommended sleep time refers to normal night time sleep. People who consistently do not get enough sleep are at higher risk of getting dementia as they age.
This is because sleep clears the protein beta amyloid that accumultates in the brain. High rates of this is associated with Alzheimer's Disease.
People who do not get enough sleep are also at higher risk of being obese, and suffer from diabetes and heart problems.
Professor Michael Chee of Duke-NUS Medical School who has done studies on sleep deprivation said: "If you can't get nocturnal sleep some napping will help.
"But, at least for adults, napping is often performed because people are terribly sleep deprived from lack of nocturnal sleep."
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