By Jonny Lupsha, Wondrium Staff Writer
The many phases of the waxing and waning Moon affect how we sleep, Science Alert reported. A study of urban and rural sleepers showed similar patterns throughout the lunar cycle despite environment. Sleep is studied with electroencephalographs.
According to Science Alert, the full Moon affects how people around the world sleep. “Humans have always been exposed to variable levels of light at night, due to reflections of sunlight from the waxing and waning Moon—and this shifting radiance stimulates us in ways we aren’t fully aware of,” the article said.
“To investigate the mystery, the researchers fitted over 500 participants with wrist-based activity monitors, to track their sleep patterns, and conducted the experiment in vastly different locales.”
The article explained that researchers tested the indigenous Toba-Qom people of Argentina, some of whom had access to no electricity, and students living in the Seattle area. Whether the sleep study participants had a night sky lit up by city lights or not, participants’ sleep and wake schedules changed similarly throughout the lunar cycle.
Sleep science is an emerging health care profession. New technologies such the invention of the electroencephalograph (EEG) have made the study of sleep science possible.
No Lies Detected
The EEG was invented by German physiologist Hans Berger and quickly rose to prominence in the study of sleep. So what does an EEG do, functionally speaking?
“EEG reveals the pattern of electrical activity in the brain,” said Dr. H. Craig Heller, the Lorry I. Lokey/Business Wire Professor of Biological Sciences and Human Biology at Stanford University, in a lecture for The Great Courses. “The brain consists of many billions of neurons, [which] process and transmit information as tiny electrical signals called ‘nerve impulses’ or ‘action potentials.’
“The EEG records patterns of electrical activity that are created by signals generated from large populations of neurons.”
An EEG is analogous to a lie detector test, or polygraph. Polygraphs record electrical activities over time and how they deviate above or below a standard line. Those electrical activities can be the breathing rate, heart rate, and so on. Dr. Heller said that an EEG measures brain waves, electrical activity of the muscles, eye movements, and sometimes heart or breathing rates, too. However, nowadays, these variables are recorded on computers instead of with a pen and paper.
EEGs measure electrical activity in the human body via electrodes, which are very fine and very sensitive electricity-conducting wires that are placed against parts of the body. Initially, two electrodes would be placed against the scalp to measure voltage changes in neuron clusters as the brain sends electrical currents throughout the body. Now, doctors use far more than two electrodes—all the way up to 256.
Electrodes that are placed on other parts of the body can measure their electrical activity as well.
“Electrodes at the corners of the eyes record eye movements—these are called electrooculograms, or EOGs,” Dr. Heller said. “Electrodes placed over the muscles record the electrical activity of those muscles and that corresponds to their state of contraction and their patterns of activity. These are called electromyograms, or EMGs.”
Finally, electrodes called electrocardiograms, or ECGs, can be used to measure the heartbeat, while devices called strain gauges can be placed on the chest to record respiration.
EEGs, EOGs, EMGs, ECGs, and strain gauges all detect tiny electrical signals over time, which help doctors monitor and study our sleep and wake cycles. This sophisticated equipment can lead to diagnoses of sleep disorders, health problems, and even how the full Moon changes our bodies—although, so far, no werewolves have been reported.
This article contains material taught by Dr. H. Craig Heller for his course Secrets of Sleep Science: From Dreams to Disorders. Dr. Heller is the Lorry I. Lokey/Business Wire Professor of Biological Sciences and Human Biology at Stanford University. He earned his PhD in Biology from Yale University.