Do You Need to Sleep 8 Hours Straight? Or Are Nighttime Awakenings Normal?

Recently, the idea that people in the past did not sleep continuously through the night — and that nighttime awakenings are simply natural — has been spreading on social media.

It is said that there used to be what was known as a “first sleep” and a “second sleep”: people went to bed shortly after sunset, then naturally woke up in the middle of the night for an hour or two, and then fell asleep again until morning. Some even claim that the idea of continuous 8-hour sleep was invented by mattress manufacturers.

So, what does modern science say?

The Historical Evidence Does Exist

Historians have found numerous documents confirming that in pre-industrial Europe, people often slept in two periods. This was one of the sleep patterns of that time. There were probably several reasons for it.

No Artificial Lighting

After sunset, natural light disappeared, and the body began to increase its production of melatonin — a hormone involved in regulating circadian rhythms and helping the body prepare for sleep.

As a result, people usually went to bed much earlier — sometimes as early as 7–8 p.m. The absence of artificial lighting supported a natural sleep-wake cycle.

What Happened Next

After the first 4–5 hours of sleep, many people naturally woke up. Historical sources describe this period of wakefulness as lasting anywhere from several minutes to one or two hours. People would then fall asleep again and sleep until dawn.

Exactly why this pattern developed is not fully understood. It is believed to have been influenced by natural circadian rhythms, the absence of artificial lighting, and significantly longer periods of darkness.

Long Winter Nights

In winter, darkness could last for 14–16 hours. Sleeping continuously for that long is physiologically difficult, so sleep may have naturally divided into two periods.

A Completely Different Lifestyle

During nighttime wakefulness, people did not sit on their phones or watch television. They might pray, read by candlelight, talk, do handicrafts, or perform quiet household tasks before going back to sleep.

But Can This Be Applied to Modern People?

Not entirely. Over the past centuries, practically everything has changed:

• artificial lighting;
• duration of daylight exposure;
• work schedules;
• stress levels;
• use of gadgets;
• lifestyle.

All of these factors influence circadian rhythms and sleep architecture. We therefore cannot directly compare the sleep of a person living in the 21st century with that of someone who lived several hundred years ago.

What Is Considered Normal Today

During sleep, the brain passes through several stages:

• N1 — drowsiness;
• N2 — light sleep;
• N3 — deep slow-wave sleep;
• REM — dream sleep.

These cycles repeat several times throughout the night. During transitions between cycles, everyone experiences brief micro-arousals of the brain. This is an absolutely normal part of sleep architecture.

Most people do not even notice them and do not remember them in the morning.

When Nighttime Awakenings Stop Being Normal

There is a fundamental difference between these physiological micro-arousals and full nighttime awakenings. If a person regularly wakes up, becomes fully conscious, cannot fall asleep again for a long time, or feels unrefreshed every morning, this is already a reason to investigate why sleep has stopped fulfilling its main function — restoring the body.

There can be many causes:

• sleep-disordered breathing;
• chronic stress;
• anxiety disorders;
• restless legs syndrome;
• chronic pain;
• hormonal changes;
• disturbances in sleep architecture;
• other medical conditions.

This is precisely why there is no universal recommendation that works for everyone.

Can a Watch or Fitness Tracker Assess Your Sleep?

Not always. A person may sleep for 8 hours but have an insufficient amount of deep sleep. Another person may sleep for the same amount of time, but their sleep may be constantly fragmented, leaving them feeling tired in the morning. That is why sleep duration is only one part of the overall picture.

Today, there are many devices that promise to improve sleep: smartwatches, rings, bedside devices, apps, sleep masks, special alarm clocks, and other solutions.

Many of them can indeed be useful as part of sleep hygiene. For example, they can help reduce phone use at night, maintain a regular sleep schedule, decrease exposure to bright light before bedtime, or make waking up more comfortable.

However, it is important to understand that no gadget on its own can eliminate the underlying cause of sleep disturbances. If a person regularly wakes up at night, does not feel rested in the morning, or experiences pronounced daytime sleepiness, the doctor’s task is not to select yet another device, but to determine why these symptoms have developed.

This is why diagnosis should always precede treatment. Only by understanding the cause can truly effective therapy be selected. Sleep hygiene measures and modern devices can be a useful addition to treatment, or can help maintain natural sleep if no serious disorders are identified.

What Can Truly Assess Sleep

Modern diagnostics make it possible to see what cannot be perceived independently. An overnight EEG sleep study allows us to assess:

• sleep architecture;
• duration of each sleep stage;
• number of micro-arousals;
• sleep continuity;
• quality of brain recovery;
• pathological changes in electrical activity during sleep.

Sometimes, this particular study helps identify the true cause of chronic fatigue, daytime sleepiness, or the feeling: “I slept all night, but I didn’t feel rested at all.”

At Longevium, we believe that quality sleep is not simply the absence of insomnia. It is one of the most important indicators of brain health, complete recovery of the body, and active longevity. That is why we aim not simply to address symptoms, but to identify their cause through objective diagnostics.

Our clinic offers overnight EEG sleep studies that assess sleep architecture, the duration of each stage, the number of micro-arousals, sleep continuity, and other parameters that cannot be assessed using fitness trackers or mobile apps.

The Main Point

The history of sleep is indeed very interesting, and biphasic sleep was probably common several centuries ago. But this does not mean that regular nighttime awakenings in modern people are always physiologically normal.

If sleep has stopped restoring you, it is important not to look for an explanation in historical traditions or rely on yet another gadget. It is important to understand what exactly is happening in your brain during sleep.

Your nighttime awakenings may be a normal variation. Or they may be a sign of a disorder affecting brain function, the cardiovascular system, metabolism, and quality of life.

If you regularly wake up at night, feel tired after sleep, experience daytime sleepiness, or simply want to objectively assess the quality of your sleep, we invite you to undergo a sleep study at Longevium.