What is normal sleep?

While you’ve probably heard normal sleep is 7-8 hours long, and maybe even that it happens in one go from 10pm to 6am, many of us don’t sleep like that. Dr Alison Bentley, Restonic Sleep Expert, says she finds people whose sleep differs from this ideal often believe they have a sleep disorder. However, that’s not necessarily the case.

Dr Bentley has been seeing patients with sleep problems for 30 years and helped to run the first diagnostic sleep laboratory in South Africa. She says there’s room for deviation from commonly cited “normal sleep” in terms of three components: duration, timing and solidity.

Duration

“In terms of duration, it is often quoted that 7-8 hours of sleep is the norm,” Dr Bentley says. “That’s not quite true. The average is 7-8 hours when looking at the duration of sleep in a population, but there are quite a few people who sleep less than that and others who need more sleep.”

If someone only sleeps five hours a night on average, they may have insomnia or they may be a naturally short sleeper. “The difference is in how they function during the day,” says Dr Bentley. “Naturally short sleepers cope well and don’t feel tired, while people with insomnia feel fatigued, with a deficit in attention resulting in poor concentration and memory difficulties.”

For short sleepers, there’s no natural way to increase the number of hours slept and that is the ‘normal’ for you.

Timing

While many people sleep between 10pm and 6am, there’s variation in terms of timing. Dr Bentley says people can be larks or owls.

“Larks go to bed early and wake early, feeling refreshed and ready to go,” she says. “Owls prefer to stay up late and sleep in later too. Whether you’re a lark or an owl is genetically determined. While it’s possible to override your natural timing, you’ll always feel a little jet-lagged if you do. Owls can wake up at 5am, but won’t feel refreshed but tired and grumpy until their usual wake-up time.”

(Image: Supplied)

Solidity

Dr Bentley says there’s a misperception that “normal” sleep happens in one solid block – uninterrupted from start to finish.

“Solidity of sleep refers to the expectation that sleep during the night should occur in one solid block,” she says. “However, we actually wake up every 90 minutes, even if we don’t know it.”

These wake-ups are very short and good sleepers don’t even remember them. Dr Bentley says it’s believed we wake up to check the environment – an evolutionary “safety feature”.

“If you extend your sleep duration by an hour, those wake-ups may also expand, meaning when you wake up normally you may stay awake for longer,” she says. “Sometimes, the first three hours of sleep stay intact with multiple awakenings after that.”

Dr Bentley says literature from centuries ago suggests it was once “normal” to go to sleep as soon as it got dark, followed by several hours spent awake during the night and another few hours of sleep before starting the day. “Sleep would be in two pieces – and that was normal then,” she says.

“Rather than worrying about whether your sleep is ‘normal’, the important thing is to feel that you have had enough sleep when you wake up – you’re not sleepy during the day. Good daytime function is a better measure of normal,” Dr Bentley says.

However, if you get the right numbers for your sleep but still feel tired and sleepy during the day, it may indicate a sleep disorder. In this case, consider speaking to a healthcare professional.

This post and content is sponsored, written and produced by Restonic.