The concept of life as a series of rhythms is an ancient one. From religious observances to modern daily routines, people have understood that life is to be lived in accordance with some sort of regular repetition. The term “biorhythm,” or biological rhythm, refers to physiological fluctuations in all living creatures.
Some argue that these rhythms are internal; others claim they are environmentally stimulated. Most likely, they are a combination of both. There are different types of biorhythms, each denoting a particular body system or fluctuation. Here are some of the types of biorhythms and what they mean.
Alpha rhythms are rapid brain waves that occur during a normal, waking state. They have a regular rhythm of 10 every second.
Like alpha rhythms, beta rhythms are brain waves, but they occur during times of intense mental and nervous activity at a frequency of 18-30 repetitions per minute.
This term may already be familiar to you. Have you ever heard of someone who works a late night shift complaining that his or her “circadian rhythm” is off? This is your internal, 24-hour clock that tells you when it’s been a full day. This is the rhythm that causes you to expect darkness and light, sleep and waking at certain times. If you’ve ever turned off your alarm clock for the weekend but still awakened at the same time, that is the result of your circadian rhythm.
These rhythms occur within the circadian or 24-hour rhythm. For example, sleep cycles that occur throughout the night are ultradian rhythms.
Infradian rhythms are fluctuations that occur at longer intervals than 24 hours, such as our routines that are based on the 7-day week. The female menstrual cycle is one such infradian rhythm, as are annual migration patterns in animals.
The study of the effect of time on the body (animal, plant, and human) is called chronobiology. Because this is a relatively new science, the shorter rhythms (such as alpha, beta, and circadian) have been studied more extensively than the longer ones.
There is another branch of chronobiology that studies fluctuations in human behavior. Proponents of this aspect of chronobiology believe that human beings’ emotional, psychological, and physical states fluctuate in accordance with external biorhythms. These chronobiologists are interested in how crime seems to come in waves, why emergency rooms are more crowded during the full moon, and so forth.