Do you know when to sleep? When to wake up? Well, you can thank your body's circadian rhythm.
Read along to explore the mystery revolving the sleep pattern we involuntarily follow!
written by suhanee verma
The human body is like an automated machine, with each part under the influence of a 24-hour timer. The term circadian rhythm involves all these 24-hour regulated parts, the sleep-wake cycle is one of them. These circadian rhythms exist primarily to influence numerous body functions such as maintaining core body temperature, energy levels, hormone balance, and appetite. As we know that every machine has a control system, in this case, it is the suprachiasmatic nucleus (SCN)* located in the brain. SCN is the central pacemaker of the circadian timing system.
How does SCN regulate the sleep-wake cycle?
Just as the different parts of a machine are connected through tubes, wires, or other connectors, the SCN is connected to the circadian rhythms through certain cells that respond to external stimuli. As and when those cells recognize changes in light, temperature, or hormone levels, they send signals to the SCN which further releases chemicals to help the brain respond. For instance, when the cells in the retina sense daylight, they send a signal to the SCN, which then releases neurotransmitters to help keep the brain alert and awake. As time passes, another chemical, adenosine starts to accumulate in the bloodstream causing a feeling of tiredness. Once the day comes to an end, a chemical called melatonin helps prepare the body for sleep. Then it is time for the regular cleaning of the machine.
This routine is ideal. In most cases, this cycle is impacted by external and internal factors which are not always in control. Factors such as age, blue light exposure, jet lag by crossing one or more time zones, caffeine, or even school/office work can alter this mechanism and result in side effects including tiredness, lack of focus, mental/sleep disorders, gain or loss of weight, etc. However, there is a certain level of control we can adapt to these factors by practicing sleep hygiene, maintaining regular sleep schedules, seeking sunlight, avoiding caffeine, exercise, and the most favorite: taking naps.
*Suprachiasmatic nucleus: A tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. It contains 20,000 neurons that oscillate autonomously
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