What is the moon phase?
The mystery of the moon stems from its transformation every night. Some nights, the floating sphere is full and shiny, and after a few weeks it will become a faint crescent shape. Although the moon seems to undergo physical changes every night, this is just an illusion caused by a complex astronomical dance.
The moon does not emit light by itself, but is illuminated by the sun. According to the positional relationship between the sun, the moon and the earth, different amounts of reflected sunlight can be seen from the earth. Our changing perspective of the Earth creates the changing shape of the Moon.
Starting from a complete disk (full moon), the moon seems to gradually shrink every night until it is completely invisible (new moon). At that time, the moon will slowly fill up until the disk is complete again. It takes 29.5 days for the moon to complete this process.
The periodic changes of the moon are divided into eight stages, each of which indicates the precise shape formed by the visible reflected sunlight, and whether the shape is increasing (increasing) or decreasing (decreasing). The eight phases are: new moon, first quarter moon, first quarter moon, first quarter moon, full moon, waning quarter moon, first quarter moon, and last quarter moon. Each stage is related to the different positions of the moon, earth and sun.
It should also be noted that the moon appears in different parts of the sky every night because it orbits the earth once a month. This repositioning affects the timing of the moonrise and moonset, delaying the moonrise by approximately 50 minutes3 per day. The full moon only occurs when it is opposite the earth and the sun, so it rises at night and sets in the morning. When the moon reaches the new moon phase, it aligns with the sun, and both rise and set together.
Does the moon phase affect sleep?
The influence of the moon on biological rhythms is well documented in nature. Changes in the diameter of trees, crab breeding patterns, spawning events in the Great Barrier Reef, and nocturnal activities of owl monkeys may all be affected by the lunar cycle. Studies on the possibility of moon phases affecting humans are not clear-most studies are on a small scale, and the results are somewhat inconsistent.
Nevertheless, convincing evidence suggests that the lunar cycle may affect sleep, and the full moon phase is the most destructive.
An analysis of a sleep study used several indicators to find that the full moon was associated with poor sleep. During this moon phase, participants needed 5 more minutes to fall asleep, sleep time was reduced by 20 minutes, the time needed to reach REM sleep was longer, deep sleep was reduced by 30%, and sleep quality decreased.
Another study found that total sleep time during the full moon was reduced by 25 minutes, while arousal and arousal increased. However, participants in this study took longer to reach REM during the new moon, which contradicts previous studies. A third analysis examined data from 319 people who underwent a one-night sleep study. People observed during the full moon have lower sleep efficiency, less deep sleep, and a delay in reaching REM sleep.
In the most extensive study on this topic, researchers analyzed sleep patterns in three indigenous Argentine communities and 464 American college students living in major cities. Regardless of the position and amount of artificial light, all groups needed more time to fall asleep one week before the full moon, and the overall sleep time was shorter.
Why does the moon affect sleep?
Many people believe that the full moon will cause sleep disruption due to the amount of sunlight reflected back to the earth. The body's internal 24-hour clock is calibrated by the rise and fall of hormone levels in response to light perception. Therefore, the light level is one of the most important factors affecting the onset and quality of sleep.
However, some people worry that the brightness of the moon is the main mechanism of sleep interruption. The brightness of moonlight is only 7% of the intensity of sunlight, which is a relatively low intensity. People are often exposed at night to artificial light that is much greater than the amount reflected by the moon. In addition, studies on sleep disruption during the full moon are usually conducted on cloudy nights or in closed, windowless environments.
Another increasingly popular hypothesis is the moon’s ability to cause electromagnetic waves on the earth. The electromagnetic field of the earth has a long tail or "magnetic tail" formed by the solar wind. When the moon orbits the earth every month, it passes through the magnetotail during the full moon phase and becomes negatively charged. Then, the magnetic charge of the moon can affect the electromagnetic field of the earth through a complex feedback process.
Current research shows that humans may be sensitive to low-level geomagnetic changes. Other geomagnetic events (such as geomagnetic storms and Northern Lights/Australia [Northern Lights/Southern Aurora]) that produce geomagnetic fluctuations comparable to those of the Moon are associated with a range of health effects, including headaches, blood pressure and blood flow changes, heart rate variability, and even heart attack. Although the exact biological basis of these changes is unclear, research has pointed to several mechanisms involving human hormone levels, DNA fragmentation, and inflammation.
The view that the gravity of the moon affects human health is based on the fact that most of the human body is water, and the gravity of the moon has a significant effect on ocean tides. Critics of this theory point out that the moon’s gravitational pull on humans is very small. Researchers estimate that the impact of the moon's tides on people is less than one millionth of the size of an atom.
During the full moon and the new moon, the gravity of the moon is also roughly equal. Therefore, any sleep changes that occur during a single moon phase are unlikely to be caused by changes in gravity alone.
Does the moon phase affect your child's sleep?
The influence of months on pediatric sleep patterns has not been well studied, and limited data are vague. A study of nearly 6,000 children in 1312 countries found that compared with the new moon phases, sleep time during the full moon was only reduced by 1%. Another analysis14 actually found that children sleep more during the full moon. Interestingly, the researchers attribute the extra sleep to increased daytime activity, but how the moon affects children’s activity levels is unclear.
A German study15 looked for the relationship between the lunar cycle, sleep, and physical activity among 1,400 adolescents. After collecting data for three years, there was no identifiable correlation between moon phases and sleep or activity levels.
Moon, sleep and mental health
The moon’s potential impact on sleep may be particularly important for people with mental illness, because many of these conditions have a two-way relationship with sleep. In fact, the word "lunacy" comes from the Roman goddess of the moon "Luna".
Recent research has highlighted the possible relationship between moon phases and symptoms of bipolar disorder. In one study, the patient's emotional cycle was often synchronized with the entire 37-year lunar cycle. The follow-up small 18 study 19 also proved the connection between the moon phases and the bipolar emotional cycle, although the exact basis is unclear.
The influence of the lunar cycle on other mental health disorders (such as anxiety and depression) has been a source of speculation. However, multiple studies 20 learning 21 assessing the link between moon phases, anxiety, and depression have yet to find relevant evidence.
Does the moon have a gender effect on sleep?
Since ancient times, the influence of the moon on female fertility has been controversial. 22. Many people believe that the moon phase controls the menstrual cycle and affects fertility. If this is true, then you can imagine a mechanism in which the moon affects sleep by acting on female hormones. It has been established that 23 sleep problems may be caused by hormonal changes during menstruation, pregnancy and menopause.
Modern studies investigating the relationship between moon phases, female reproductive patterns, and sleep are contradictory. A study spanning 15 years found that participants' menstrual cycles intermittently synchronize 24 with the moon phases, and menstruation occurs before the full or new moon.
Use the period tracking smartphone app to analyze women's data and look for correlations 25 between falling asleep, menstruation, and moon phases. There is no correlation between menstruation and moon phases. However, those who started when the moon was half full reported better sleep. Women who start their menstrual cycle when the moon is less than half full usually sleep poorly.
There are few studies comparing the sleep effects of men and women by month. However, some studies have notable findings. In another study comparing moon phases and sleep patterns, female participants had less sleep time, decreased sleep in stage 4, and decreased REM sleep around the full moon. 26. Male participants increased REM during the full moon. Other studies have pointed out that men and women have slightly different sleep indicators during the full moon, but the results are inconsistent and often contradictory.
Tips for sleeping better
Although there are some compelling studies suggesting that the moon phase may affect sleep, at this point, the study is only suggestive. There are many things we don't understand about this topic. Fortunately, there are some evidence-based strategies that will allow you to sleep well tonight, regardless of the influence of celestial bodies.
Sleep hygiene is one of the most approachable and useful ways to get a good night's sleep. This includes adjusting your bedroom environment and practicing certain behaviors to help you fall asleep successfully. Simple things like making sure your bedroom is dark, limiting caffeine, avoiding blue light and keeping a sleep schedule can go a long way.