Napping Twice Daily: A Better Sleep Strategy?

Is it better to sleep twice a day? This is a question that has puzzled people for centuries. In pre-industrial times, segmented sleep, or biphasic sleep, was the norm. People would sleep in two chunks, with a waking period in between. Today, however, the conventional approach is monophasic sleep, where we sleep in a single block of time overnight. So, which is better for our health?

Some researchers argue that segmented sleep is more natural and can increase alertness and flexibility. It can also be a more realistic goal for shift workers. On the other hand, others claim that segmented sleep disrupts our circadian rhythm and prevents us from getting enough deep sleep, which is essential for restoration and physical recovery.

So, while there may be benefits to sleeping twice a day, it is important to consider the potential risks to our health. The best sleep pattern for each individual may vary, and it is always a good idea to consult a doctor or sleep expert for personalized advice.

Segmented sleep may lead to sleep deprivation

Segmented sleep, or biphasic sleep, is a sleep pattern where an individual sleeps twice per day, typically for a long duration at night and a shorter period during the day. While this may have been the natural human sleep pattern in pre-industrial times, it may lead to sleep deprivation in today's society. Here are some reasons why segmented sleep may result in sleep deprivation:

• Disruption of Circadian Rhythm: Our bodies follow a 24-hour circadian rhythm that regulates our sleep-wake cycle, alertness, and hunger. Segmented sleep, with its daytime naps, goes against these natural cues, making it harder to attain deep sleep during the day.
• Reduced Overall Sleep Time: Segmented sleep often results in a reduced total sleep time. For example, a person might sleep for 5-6 hours at night and take a 30-minute nap during the day. This fragmented sleep pattern may not provide enough time for the body to complete its sleep cycles and enter the deep, restorative sleep needed for optimal health.
• Impact on Sleep Architecture: Our bodies cycle through four stages of sleep, and it is essential to get enough of the deep, non-REM sleep for a proper reset. Segmented sleep can disrupt this sleep architecture, leading to insufficient deep sleep and potential health issues.
• Risk of Sleep Disorders: Maintaining a consistent sleep schedule is crucial for regulating our body's internal clock. Abruptly switching between segmented sleep and monophasic sleep (sleeping in a single block) can confuse our body's rhythm, potentially triggering sleep disorders like insomnia.
• Practical Challenges: Today's society often doesn't accommodate segmented sleep. Most individuals have work and family commitments that require them to conform to the standard sleep/wake schedules. Deviating from these schedules can lead to social and practical challenges, making it difficult to maintain a segmented sleep pattern.
• Health Risks: Sleep deprivation caused by segmented sleep can have serious health consequences. The National Heart, Lung, and Blood Institute warns that insufficient sleep increases the risk of high blood pressure, depression and anxiety, heart disease, diabetes, and obesity.

While segmented sleep may work for some individuals, it is essential to prioritize getting sufficient, quality sleep. If you must follow a segmented sleep schedule, aim for a total of 7-9 hours of sleep in 24 hours and maintain a consistent sleep routine to minimize potential disruptions to your body's natural rhythms.

Biphasic sleep is a healthier sleep pattern than monophasic sleep

Biphasic sleep involves two sleep periods: a longer nighttime sleep and a shorter daytime nap. This type of sleep pattern is also known as segmented or bimodal sleep. While monophasic sleep is the most common sleep pattern, with people sleeping for seven or eight hours straight each night, biphasic sleep has been argued to be a more natural and healthier alternative.

Firstly, biphasic sleep is believed to be more in tune with our body's internal circadian rhythm, which is responsible for our sleep-wake cycle. Our body clock naturally lends itself to a biphasic sleep schedule due to the reduction in alertness and the so-called 'post-lunch dip' in the early afternoon. This is supported by historical evidence, which suggests that segmented sleep used to be the norm in pre-industrial times, with people often waking up for a couple of hours in the middle of the night.

Secondly, biphasic sleep can lead to increased alertness and productivity throughout the day. Sleeping in two periods can result in two periods of increased activity and creativity, as sleepiness does not build up during a long wake period. A 2016 study found that having two separate sleep periods provided "two periods of increased activity, creativity and alertness across the day". Additionally, napping has been linked to improved cognitive performance, with shorter naps boosting alertness and longer naps producing cognitive benefits that last longer.

Finally, biphasic sleep can offer more flexibility to individuals, allowing for better work-life balance. This type of sleep pattern can be especially beneficial for shift workers, as it provides them with at least some opportunity to sleep at night and reduces the need to sustain alertness for extended periods.

However, it is important to note that biphasic sleep may not be feasible or suitable for everyone due to work or family commitments. Additionally, there is a potential risk of sleep deprivation if the timing of sleep periods is not carefully planned. Overall, while biphasic sleep offers several benefits over monophasic sleep, it is essential to consider individual circumstances and ensure that total sleep time remains adequate.

The benefits of napping include improved memory and alertness

Napping has been proven to have a plethora of benefits, including improved memory and alertness. A 2016 study from the Centre for Sleep Research at the University of South Australia found that having two separate sleep periods provides "two periods of increased activity, creativity and alertness across the day, rather than having a long wake period where sleepiness builds up across the day and productivity wanes."

Napping can also improve memory. Studies have shown that sleep plays an important role in storing memories. A nap can help you remember things learned earlier in the day as much as a full night's sleep. Napping works to keep you from forgetting things like motor skills, sense perception, and verbal recall, too.

The ideal nap length is between 20 and 30 minutes. This helps you wake up feeling refreshed without falling into deep sleep. Napping for longer than 30 minutes can cause grogginess and even worsen sleepiness.

Napping may also be beneficial for shift workers who struggle to get enough sleep and need to be alert at irregular times. It can also be a good way to combat the effects of jet lag or a temporary change in your sleep schedule.

However, it's important to note that napping may not be suitable for everyone. Some people may find that napping interferes with their nighttime sleep or causes them to feel more tired during the day. It's essential to listen to your body and find what works best for you.

Circadian rhythms are negatively impacted by artificial light at night

Circadian rhythms are physical, mental, and behavioural changes that follow a 24-hour cycle, responding primarily to light and darkness in an organism's environment. They are governed by a small part of the brain known as the circadian pacemaker, which is influenced by light exposure.

Artificial light at night can negatively impact the circadian rhythm in the following ways:

• It can cause a person's circadian rhythm to be misaligned with the day-night schedule, throwing their sleep patterns out of whack.
• It can induce health issues such as worsened metabolism, weight gain, cardiovascular problems, and possibly an elevated cancer risk.
• It can suppress the production of melatonin, a sleep-promoting hormone that increases drowsiness and normalises the circadian rhythm.
• It can hinder transitions between sleep cycles, reducing the quality of sleep and causing repeated awakenings.
• It can contribute to the development of circadian rhythm sleep-wake disorders, such as jet lag and shift work disorder.

Blue light, in particular, has been found to have more potent effects on melatonin suppression and circadian rhythm disruption than other types of light. Blue light is emitted by many electronic devices and LED lights, increasing our exposure to it, especially after sundown.

Split sleep schedules may be a more natural rhythm for some people

There is some evidence that split sleep schedules, also known as biphasic sleep, may be a more natural rhythm for some people.

Biphasic sleep is when someone sleeps twice per day, sometimes referred to as a siesta sleeping pattern. This type of sleep pattern typically involves a long duration of sleep at night (around 5-6 hours) followed by a shorter period of sleep during the day (around 30 minutes to 2 hours).

Historically, segmented sleep (a type of biphasic sleep with two sleep periods at night) was the norm. In pre-industrial times, people often slept in two shifts, with a waking period in between. Anthropological evidence suggests that during pre-industrial Europe, sleeping in two chunks was considered normal. Historian A. Roger Ekirch's book, *At Day's Close: Night in Times Past*, describes how households at this time would retire a couple of hours after dusk, wake up a few hours later for one to two hours, and then have a second sleep until dawn.

Some researchers argue that segmented sleep is the most natural of all sleeping patterns. A study by the National Institute of Mental Health found that when people were exposed to 10 hours of light per day (similar to a winter's day), they got their shut-eye in two chunks, with a few hours awake in between. This is similar to the sleep patterns of animals.

Dr Melinda Jackson, a psychologist specialising in sleep disorders, and Dr Siobhan Banks, a sleep researcher, claim that sleeping in two chunks may increase alertness during the day and provide people with more flexibility to carry out work and spend time with their family. They also believe that the traditional Spanish siesta, which involves a two- to three-hour lunch break and nap in the early afternoon, is more in line with our body clock due to the natural reduction in alertness during this time.

In support of this, there is growing evidence that naps can have important benefits for memory and learning, increasing alertness, and improving mood. A 2016 study from the Centre for Sleep Research at the University of South Australia found that having two separate sleep periods provided "two periods of increased activity, creativity and alertness across the day, rather than having a long wake period where sleepiness builds up across the day and productivity wanes."

Some believe that sleep disorders, like sleep maintenance insomnia, may be rooted in the body's natural preference for split sleep. Therefore, split sleep schedules may be a more natural rhythm for some people.

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