For most of our lives, we are told that a good night's sleep means getting eight hours of uninterrupted rest. But people in pre-industrial Europe sometimes followed a very different routine: they went to bed, woke up for a while in the middle of the night, and then returned to sleep until morning. This pattern was known as “first sleep” and “second sleep,” and it raises an interesting question: were we always meant to sleep the way we do today? Our sleep habits have changed alongside the world around us. Artificial lighting allows us to stay awake long after sunset, while work schedules and daily responsibilities shape when we go to bed and get up. Today, some people even experiment with polyphasic sleep, dividing their rest into several shorter periods throughout the day. But changing when and how we sleep does not necessarily mean our bodies can thrive on less rest. We asked several specialists what research tells us about human sleep patterns and what it really means to sleep well. They explain what makes segmented sleep different from extreme polyphasic schedules, why getting enough quality rest matters, and what people can do when their sleep becomes disrupted. From historical sleep habits to modern attempts to make the most of every waking hour, there is more to healthy sleep than simply following a familiar routine. Understanding how our bodies respond to different sleep patterns can help us separate intriguing ideas from habits that may leave us feeling worse. moviafilmes / Magnific (not the actual photo) Most of us have grown up thinking that a good night's sleep means going to bed at a reasonable hour and waking up eight hours later. But healthy sleep is about more than following a familiar schedule. The Centers for Disease Control and Prevention recommends that adults aged 18 to 60 get at least seven hours of sleep per night, while also emphasizing the importance of sleep quality. Getting enough hours is only part of the picture. Quality sleep should leave you feeling refreshed and allow you to stay alert throughout the day. If you regularly wake up during the night, struggle to fall asleep, or still feel tired after what should have been a full night's rest, you might not be getting the quality sleep your body needs. Sleep also plays an important role in how we function when we're awake. According to the CDC, getting enough sleep can help improve attention and memory, support a healthy metabolism, reduce stress, and improve mood. Over time, consistently missing out on sleep can also increase the risk of health problems, including heart disease, high blood pressure, and type 2 diabetes. So, while the number of hours we sleep matters, the bigger question is whether our sleep allows us to recover and function well. This distinction becomes especially important when we look at the different ways people divide their sleep. A schedule that looks unusual isn't necessarily unhealthy, just as spending enough time in bed doesn't guarantee a restorative night's rest. To understand the difference, we need to look beyond the clock and examine how our sleep is structured. Cristian Manieri / Pexels (not the actual photo) Historical accounts suggest that some people in pre-industrial Europe followed a routine known as “first sleep” and “second sleep.” They would go to bed in the evening, wake up for a while during the night, and then return to sleep until morning. However, historians cannot be sure how widespread this practice was or whether it represented the norm. Dr. Muhammad Qasim, a pulmonology and sleep medicine specialist, explains that human sleep patterns can be flexible, particularly in response to light exposure. Sleeping through the night and taking a short afternoon nap, for example, is a form of biphasic sleep. Dr. Qiao Yufei, MD at Mediway Medical, also notes that laboratory research suggests sleep can occur in two longer periods separated by wakefulness, although this does not mean everyone should adopt that pattern. Polyphasic sleep takes this idea further by dividing rest into several periods throughout the day. Some schedules are designed to reduce the total time spent sleeping, but Qasim distinguishes these from simply adding a nap to a full night's rest. Qiao similarly warns that artificially restricting sleep through multiple short periods can harm alertness and performance, with no established health or performance benefits. Historical sleep patterns are also more complicated than they might seem. A 2023 review in Medical History questioned whether references to “first sleep” and “second sleep” prove that segmented sleep was widespread. The key distinction is that humans may sleep in different ways, but a historical pattern or an alternative schedule is not automatically healthier than getting enough restorative sleep. cottonbro studio / Pexels (not the actual photo) Our bodies rely on cues from the environment to know when it is time to sleep and when it is time to wake up. Light is one of the strongest signals, helping regulate our internal body clock, also known as the circadian rhythm. As evening approaches, the body produces melatonin, a hormone that helps prepare us for sleep. But bright artificial light from phones, computers, and televisions can interfere with this process and make it harder to fall asleep. This is one reason our modern routines can affect how well we rest. Staying up late under bright lights may send the brain signals that it is still daytime, even when the body should be preparing for bed. The National Heart, Lung, and Blood Institute recommends getting more natural light during the day and limiting artificial light at night to help keep the sleep-wake cycle aligned with the environment. Naps can also influence nighttime sleep, although their effects depend on when and how long we sleep. A short nap can help improve alertness, but sleeping during the day may make it harder to fall asleep at night, particularly for people who already struggle with nighttime rest. The NHLBI advises avoiding daytime naps, especially in the afternoon, when managing circadian rhythm disorders, while recognizing that some shift workers may benefit from a short nap before work. Dr. Yufei recommends keeping naps to 20 minutes or less in the early afternoon. The goal is not to eliminate every daytime nap or avoid artificial light completely, but to understand how these habits affect our natural sleep-wake rhythm. By getting daylight during the day, dimming lights in the evening, and timing naps carefully, we can make it easier for our bodies to recognize when it is time to rest. Polina / Pexels (not the actual photo) There is a difference between dividing sleep into several periods while still getting enough rest and deliberately cutting back on sleep to gain more waking hours. The second approach is common among people who experiment with polyphasic sleep schedules, which can involve several short naps spread across the day instead of one main period of nighttime sleep. Some schedules even aim to reduce total sleep to just a few hours a day. A 2021 review published in Sleep Health examined the evidence on polyphasic sleep and found no scientific support for claims that these schedules improve health or performance. Instead, the researchers concluded that schedules that significantly reduce sleep or deliberately fragment it may have negative effects on physical and mental health, mood, and daytime performance. They also stressed that the available research has limitations, so the evidence does not establish that every form of split sleep is harmful. Dr. Qiao Yufei similarly warns that artificially restricting sleep can impair alertness and performance. Dr. Muhammad Qasim adds that regularly cutting sleep short or fragmenting it can affect memory, mood, metabolism, and cardiovascular health. Feeling as though you have adapted to a demanding schedule does not necessarily mean your body is getting the rest it needs. Dr. Jason Schroder, Co-Founder and Medical Director at Craft Body Scan, also highlights an important distinction: some people spend enough time in bed but still feel exhausted because pain or breathing problems repeatedly wake them up. Sleep apnea, for example, can interrupt nighttime rest without a person fully realizing it. Whether the problem comes from sleeping too little or from frequent awakenings, persistent daytime tiredness is a reason to look more closely at sleep quality rather than simply trying to fit more activities into the day. Miriam Alonso / Pexels (not the actual photo) When sleep becomes disrupted, the first step is to look at the habits and circumstances that might be getting in the way of a good night's rest. Dr. Qasim recommends starting with a consistent wake-up time, getting outdoor light in the morning, and limiting caffeine later in the day. Dr. Yufei also suggests keeping the bedroom cool and quiet and reducing artificial light in the evening. Consistency matters because our bodies rely on regular cues to regulate the sleep-wake cycle. The National Institute of Neurological Disorders and Stroke explains that sleep supports learning, memory, concentration, mood, and many other functions throughout the body. Keeping a regular schedule and allowing enough time for rest can help protect these functions and make it easier to stay alert during the day. It is also important to understand when changing habits may not be enough. Dr. Jason Schroder recommends tracking sleep schedules and nighttime awakenings to help identify possible causes of disrupted rest. Pain, loud snoring, gasping, or persistent daytime tiredness can point to an underlying problem that needs medical attention. For people with chronic insomnia, cognitive behavioral therapy for insomnia (CBT-I) is an evidence-based treatment recommended by sleep professionals. Ultimately, restoring healthy sleep is not about forcing the body to follow a particular historical pattern or finding a way to function on less rest. It means getting enough good-quality sleep, keeping a sustainable routine, and addressing problems that prevent the body from recovering properly. Sleep supports nearly every aspect of our health, so making room for it is not time wasted. It is a crucial part of taking care of ourselves. Andrej Lišakov / Unsplash (not the actual photo)
