Most people have heard of circadian rhythm and know that we have an internal clock which regulates sleep, hunger and energy levels. Most people know that it is regulated by light levels. This body clock, the circadian rhythm, is about 24 hours long and even the simplest bacteria have a circadian rhythm of the same duration. This daily cycle influences brain-wave activity patterns, cell repair and hormone levels.
Many, many years ago people noticed that humans, plants and animals have daily cycles of sleep and hunger. The first known written record is from a 13th-century Chinese medical textbook. In 1729 Jean-Jacques de Mairan recorded observations of a plant “waking and sleeping” even if kept in the dark.
The circadian clock affects us more than when we feel sleepy. So far scientists have discovered at least 35 conditions known to be affected by the circadian clock. Some examples are blood pressure is lowest at 3 a.m., during deep sleep, and highest when we wake up so there are more heart attacks and strokes between 8 a.m. and midday. Asthma attacks are worse during daylight as the body creates a natural anti-inflammatory during nighttime while cells grow and repair more quickly during daylight.
This has created a new field of medicine, chronotherapy. These studies have caused changes in how lighting systems (periods of light and dark) in the hospital have been changed for premature infants to the elderly. It is helping us to know what time to give medicine so they are most effective, ranging from baby aspirin to chemotherapy. The differences in effectiveness of some medications given in the morning or the evening is amazing.
Most people don’t think of about genes that regulate circadian rhythm. We now know that we have thousands and thousands of genes that are the basic machinery of the body, producing proteins and sending messages to all the organ systems in the body. Some are now identified as “clock” genes that are active in all our organs. There is a gene that regulates if a person is a morning person or night owl. A gene that regulates if a person needs more or less sleep than the average recommended. These genes establish your chronotype and do run in families.
Chronotypes cannot be changed but do change with age. Infants have not developed a circadian rhythm but do so over the first 2-3 months. Most young children experience high energy in the morning while teenagers peak in the afternoon. Teenager tend to have a circadian rhythm that makes it hard to get up in the morning. By adulthood the individual circadian rhythm is settled.
There are abnormal circadian cycles (external, caused by the environment like shift work, or internal, such as a gene mutation) that can cause complications such as heart disease, thinking dysfunction, obesity, depression and anxiety. Another external cause is the blue light from mobile phones, computers and TV in the hours before bed that affect the circadian cycle and can contribute to circadian rhythm disorders.
Source:https://www.galvnews.com/
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