The National SLEEP Foundation guidelines1 advise that healthy adults need between 7 and 9 hours of sleep per night. Infants, young children and adolescents need even more sleep to allow for growth and development. People over the age of 65 should also get 7-8 hours of sleep per night. Future studies should seek to better inform contemporary sleep duration recommendations by examining dose-response curves with a wide range of health outcomes.
Although international normative data provide information on the normal distribution of sleep duration in the population, they do not identify the duration associated with health benefits. It has also been defined as the daily amount of sleep that allows an individual to be fully awake (i.e. sleep deprived) and able to maintain normal levels of performance during the day. Recommendations on sleep duration serve as a guideline for public health, but should be individualised for each patient in the clinic.
However, the exact amount of sleep that should be obtained each night to optimise all health-relevant outcomes is neither simple nor ubiquitous, as the optimal amount for one outcome may not be the same for another outcome (e.g. 9 hours of sleep per night might be ideal for sports performance, while 7 hours might be best for academic performance). Consumers are also increasingly interested in using fitness trackers and smartphone apps to assess their sleep. For children, getting the recommended amount of sleep on a regular basis is associated with better health, including improved attention, behaviour, learning, memory, ability to control emotions, quality of life, and mental and physical health.
However, intentionally restricting sleep for a prolonged period of time (i.e. chronic sleep deprivation) is not a good idea and can affect health and safety. Recommendations on sleep duration (public health approach) are appropriate to provide guidance from a population point of view, while advice at the individual level (e.g. in the clinic) should be individualised to the reality of each person.