1. How sleep works during lunchtime breaks.
Napping is an important part of the circadian rhythm, helping the body regenerate energy, improve alertness, and enhance work performance. Whether occurring during the day or at night, sleep goes through several stages necessary to maintain physical and mental health.
Stage 1: This is the lightest and shortest stage of sleep, lasting only one to seven minutes.
Phase 2: This phase follows Phase 1 and lasts approximately 10 to 25 minutes. During Phase 2, muscles relax and bodily functions slow down. However, sleep in this phase is still relatively light.
Stage 3: This is a deeper, more restorative stage of sleep, and it can be difficult to wake up during this phase. Stage 3 typically lasts from 20 to 40 minutes.
Rapid eye movement (REM) sleep: During REM sleep, the body's muscles are temporarily paralyzed and the eyes move rapidly under closed eyelids. Dreams often occur during REM sleep.
When sleep lasts for several hours, the body goes through these stages multiple times. However, during a nap, there isn't enough time to go through multiple sleep cycles.
In fact, during a short nap, a person may not get enough sleep, or even spend any time in the REM sleep stage (stage 3). This can actually make it easier for the body to wake up feeling more alert. Longer naps, such as those lasting more than 30 minutes, can cause sleepers to enter deep sleep, and feel sluggish due to being awakened during this stage.
Short afternoon naps, which involve periods of deep sleep, help the body wake up feeling more refreshed.
2. How does napping benefit the brain?
When the brain doesn't get enough rest, the body is more likely to feel tired and less alert the next day. People who are sleep-deprived often have difficulty concentrating, absorbing information, solving problems, and making decisions. In addition, their reflexes are slower, increasing the risk of accidents or falls.
Numerous studies in the US have shown that a short nap in the afternoon can significantly improve brain function. A 2021 study noted that people aged 60 and older who regularly took naps performed better on memory tests than those who did not. These naps lasted a minimum of 5 minutes and no more than 2 hours.
In addition, another study showed that naps under 30 minutes help reduce the risk of cognitive decline in people aged 65 and over. Meanwhile, research from University College London, UK, indicates that napping may slow down age-related brain atrophy.
Furthermore, as we age, many brain regions involved in learning and memory gradually shrink. However, taking a proper nap can help maintain brain volume, a factor directly related to cognitive ability and mental clarity.
Besides supporting brain function, short naps also help restore energy, reduce daytime fatigue, and improve work performance. Several studies suggest that napping can improve memory, logical reasoning, the ability to handle complex tasks, and physical performance. For example, athletes may improve endurance and reaction time after napping. Some small trials have also shown that short naps help reduce stress and support the immune system in people who were sleep-deprived the night before.
However, napping isn't always beneficial. One 12-year study found that older men who napped for two hours or more each day had a higher risk of cognitive decline compared to those who napped for less than 30 minutes. Another study in China also showed that napping for more than 90 minutes increased the risk of stroke by 25%.
3. Tips for a healthy afternoon nap
For afternoon naps to be truly beneficial for health and brain function, attention should be paid to the timing, location, and duration of the nap.
Timing: The ideal time for a nap is between 1 PM and 3 PM, when the body enters its natural phase of reduced alertness during the day. Napping later can disrupt the natural sleep-wake cycle, making it difficult to fall asleep at night and leading to fatigue the next day.
Duration: It is recommended that adults take a nap for about 20 minutes, and it should not exceed 30 minutes. This amount of time is sufficient for the body to experience light sleep that increases alertness without entering deep sleep.
In some special cases, such as emergency responders or night shift workers, a nap lasting around 90 minutes can be helpful as this allows the body to complete a full sleep cycle without interrupting deep sleep. However, napping too much or too late can negatively impact nighttime sleep. Relying on daytime naps instead of maintaining a regular nighttime sleep schedule can also easily disrupt the circadian rhythm.
Environment: The sleeping environment also plays an important role. A quiet, dark, cool, and comfortable environment will help the body fall asleep more easily. Using blackout curtains, earplugs, eye masks, or listening to soothing sounds like rain or ocean waves can help reduce distractions and make it easier to fall asleep.
Set an alarm: This is essential to avoid napping for too long. Recommendations suggest limiting naps to 40 minutes or less to avoid feeling groggy upon waking.
Drinking coffee before a nap: Although it may sound counterintuitive, this is true because caffeine blocks adenosine, a chemical that accumulates during the day and causes drowsiness. Therefore, when you drink coffee right before a nap, the caffeine eliminates adenosine while your body is sleeping, helping you feel more refreshed and alert.
However, if you can't take a nap, don't stress too much about it, because simply closing your eyes, relaxing, and taking deep breaths can still help your mind rest.
Source: https://suckhoedoisong.vn/cach-ngu-trua-dung-de-phuc-hoi-nao-bo-169260511162553391.htm
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