Is it true that the sleep we get before midnight is the most important kind?

There’s plenty of theories thrown around when it comes to sleep – from proper ‘sleep hygiene’ to the best beds and mattresses to aid the snooze, as well as alternative therapies and ‘get to sleep in minutes’ hacks.

But the key might be all in the timing. We know that 7 to 9 hours is optimal for most of us, but what about when we’re sleeping? According to some, the sleep we get before midnight is more beneficial for the body, due to our natural body clock (or circadian rhythm).

The old wives’ tale goes that ‘sleep before midnight counts double’, or ‘an hour’s sleep before midnight is worth two after’, and it turns out there might be some truth in the sayings. GLAMOUR enlisted the help of sleep physiologist Dr Guy Meadows – who is co-founder and clinical lead at Sleep School – to find out whether we really should be snoozing before the clock strikes twelve.

Is it true we get our best sleep before midnight?

A lot of the time, but it’s more to do with when you naturally feel sleepy, according to Guy. “Humans are designed to sleep at night, but the exact timing of sleep varies from one person to another depending on our genetics,” he says. “Whilst many of us benefit from going to bed before midnight, research suggests that around 28% of us have what is known as a ‘delayed sleep phase’, meaning we naturally feel like going to bed later and waking up later. For these so-called ‘evening types’ or ‘owls’, choosing to sleep according to their natural ‘later’ sleep timing works best.”

He also notes that it’s difficult to determine what ‘best sleep’ might actually mean. “Deep sleep is often referred to as the ‘best’ type of sleep because of its helps us to wake up feeling refreshed. In actual fact, good quality sleep is defined as getting complete cycles of light, deep and Rapid Eye Movement sleep stages, across an entire night.”

Why do most people want to sleep before midnight?

After the sun goes down, most of us start to feel naturally sleepy. “The light-dark cycle is connected to the sleep-wake cycle,” says Guy. “Light is the signal for wakefulness and darkness is for sleep. The amount of light in the environment is detected by light-sensitive cells in the eyes; this signals to our brain’s internal body clock that it needs to be awake or asleep. For example, the detection of darkness triggers the body clock to stimulate the pineal gland to release the sleep promoting hormone melatonin, preparing the mind and body for sleep.”

Why should we sleep according to our body clock, or circadian rhythm?

“The body clock is a group of 20,000 clock cells behind the eyes that work like a clock, telling the brain what time of day it is. It keeps our biological processes running to a 24-hour schedule known as our circadian rhythm. It tells them when to be switched on or off. It tells us when to sleep, when to feel hungry and numerous other things. Everything is under its control. 

“If our circadian rhythm remains steady, all biological processes work like clockwork. We sleep better and feel healthy. Stay up late or have long lie-ins, and it confuses the body clock. A confused body clock leads to ‘social jet lag’, which leaves us feeling mentally and physically tired and causes bad sleep.”

What about night owls, who rarely get to sleep before midnight?

Guy advises: “We would aim to find out when they naturally feel like sleeping and waking. If they’re an evening type, then this might be the best time for them to sleep and so it’s no cause for concern. 

“If not, then we would want to understand what factors could be preventing them from falling asleep earlier such as stress, late working, lifestyle habits (for example late eating and exercising or excessive light stimulation from digital tech). Another avenue of enquiry would be to determine whether they have a sleep disorder such as sleep onset insomnia and then treat accordingly.”