{"id":3882,"date":"2019-12-23T13:10:18","date_gmt":"2019-12-23T12:10:18","guid":{"rendered":"https:\/\/disturbmenot.co\/?p=3882"},"modified":"2020-06-05T00:53:37","modified_gmt":"2020-06-04T22:53:37","slug":"what-is-the-circadian-rhythm","status":"publish","type":"post","link":"https:\/\/disturbmenot.co\/what-is-the-circadian-rhythm\/","title":{"rendered":"What Is the Circadian Rhythm and How Does It Affect Sleep?"},"content":{"rendered":"

Have you ever noticed that you feel amazing in the evenings, but lack energy in the mornings? Have you ever wondered about the scientific explanation for the difference between night owls and early birds? Well then, perhaps you should first be asking, <\/span>what is<\/span> the <\/span>circadian rhythm?\u00a0<\/span><\/p>\n

Understanding this part of our biology, both in practicality and in the scientific sense, can help us get more control over our lives\u2014and our health. We can quickly define the circadian rhythm as a biological cycle that lasts for 24 hours every day. Within the 24-hour cycle, this rhythm influences our hormones, eating habits, and body temperatures, not to mention our sleep-wake cycles.<\/span><\/p>\n

Know that the <\/span>circadian rhythm<\/span> is present <\/span>in plants<\/span>, animals, and fungi\u2014not just humans. It\u2019s absolutely central to our daily lives, our habits, and our health. In fact, the 2017 Nobel Prize in Physiology or Medicine was awarded to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for their research and discoveries pertaining to these biological cycles.<\/span><\/p>\n

Below, you can find more information on the circadian rhythm, its scientific basis, and how it influences our lives and habits.<\/span><\/p>\n

What Is the Difference Between<\/b> One\u2019s <\/b>Circadian Rhythm and Biological Clock?<\/b><\/h2>\n

Before continuing, you need to understand the difference between the circadian rhythm and our biological clock. Namely, the circadian rhythm, or rather rhythms, can also be defined another way: they are the physical, mental, and behavioral changes a person experiences within a 24-hour cycle.\u00a0<\/span><\/p>\n

Meanwhile, our <\/span>biological clock<\/span> is something similar, but still a little different because it\u2019s a more inclusive term. Namely, a good definition of this process follows the fact that this is our innate timing device. Our biological clock actually leads to the occurrence of the circadian rhythm (as well as other biological rhythms) within the body.<\/span><\/p>\n

How Does the Circadian Rhythm Work?<\/b><\/h2>\n

A simple answer is that the <\/span>hypothalamus<\/span>, by <\/span>definition<\/span>, is in charge of the circadian rhythm. But to give a little more detail, the circadian rhythm is controlled by a cluster of nerves found within the hypothalamus, known as the suprachiasmatic nucleus (the SCN). This cluster of nerves basically makes up the biological clock we mentioned earlier. Now that you know <\/span>what regulates circadian rhythms<\/span>, how does all this actually work?<\/span><\/p>\n

The purpose of the SCN is to respond to varied environmental cues (for example, they\u2019re the reason we feel tired once night falls). Some of these cues (also known as zeitgebers) are light levels, our eating habits, and our physical activity levels at certain points in time.<\/span><\/p>\n

Once we experience some of these cues, they trigger the appropriate reactions within our bodies\u2014things like our metabolism, <\/span>sleep<\/span><\/a>, mood, and body temperature, as well as our <\/span>melatonin <\/span>secretion. And it\u2019s this melatonin secretion that leads to the common connection between <\/span>circadian rhythms <\/span>and sleep.<\/span><\/p>\n

Namely, melatonin is known as the \u201csleep hormone.\u201d Produced by the pineal gland, it\u2019s activated by one of the aforementioned environmental cues, most often when our retina detects lower light levels (i.e., darkness falling outside). Melatonin then prepares our bodies for sleep.<\/span><\/p>\n

Comprehensive <\/span>research<\/span><\/a> has shown that melatonin is vital for sleep, and many people take it in supplement form in order to improve their sleep quality. It also regulates blood pressure, our cortisol levels and immune functions, and also our body\u2019s antioxidant defenses.<\/span><\/p>\n

A healthy circadian rhythm will lead to the production of melatonin several hours before one goes to bed and will peak somewhere around five hours after falling asleep.\u00a0\u00a0<\/span><\/p>\n

What Are Examples of Circadian Rhythms?<\/b><\/h2>\n

\"What<\/span><\/p>\n

This is a common question that hinges more on semantics than it does on actual biology. Namely, on one level, you can understand that some examples include things like our sleep-wake cycles, hormone secretion cycles, and body-temperature cycles. However, these can also be seen as actions and processes within the body that are in fact merely governed by the circadian rhythm.\u00a0<\/span><\/p>\n

Why Is the Circadian Rhythm Important?<\/b><\/h2>\n

Your circadian rhythm isn\u2019t just about you getting a good night\u2019s sleep. Rather, it has a substantial impact on your health and overall wellbeing. For example, a <\/span>study<\/span><\/a> that included over 8000 employees showed interesting results. Of these participants, some worked standard \u201cnine-to-five\u201d jobs, while others had shift-based employment. The shift employees tended to get sick more, often suffering from a range of infectious diseases.<\/span><\/p>\n

The <\/span>human circadian rhythm<\/span> influences our hormones and metabolism. It can also help us regulate blood sugar levels. Namely, our insulin levels are higher during the day than they are at night\u2014and turning this on its head can mess up our blood sugar regulation. When these processes are functioning properly, you\u2019ll have more energy during the day, as well. After all, your <\/span>body clock <\/span>dictates when the mitochondria, the powerhouse of the cell, will release energy. Throwing this off-balance leads to disrupted sleep and low energy levels during the day.<\/span><\/p>\n

In fact, disrupting our natural circadian rhythm by not sticking to a regular sleep schedule leads to <\/span>cardiovascular health<\/span><\/a> problems, an increase in weight gain, insomnia, mood changes, and so on. Nearly any issue that comes with disrupted hormones and a messed-up metabolism will be linked to a disrupted circadian rhythm.<\/span><\/p>\n

What Is a Normal Circadian Rhythm?<\/b><\/h2>\n

No circadian rhythm is strictly set in stone. While there are of course certain fixed points\u2014like the fact that the circadian rhythm is greatly influenced by light\u2014people\u2019s rhythms generally vary.\u00a0<\/span><\/p>\n

A <\/span>study<\/span><\/a> published in <\/span>Sports Medicine<\/span><\/i> shows that there are distinct differences in cognition for people based on the time of day. People defined as night owls have a tough time waking up in the mornings and have more energy later in the day. However, it seems that the <\/span>internal clock<\/span> works differently for early birds, who are full of pep earlier in the day.\u00a0<\/span><\/p>\n

The reasoning behind these distinctions can be found in the actual name \u201ccircadian.\u201d Namely, it comes from <\/span>circa<\/span><\/i>, meaning \u201caround,\u201d and <\/span>diem<\/span><\/i>, meaning \u201cday.\u201d This \u201caround\u201d part is vital. First, it refers to the fact that these rhythms do, indeed, revolve around a single day. However, \u201caround\u201d can also mean approximately. The <\/span>circadian rhythm in humans<\/span> isn\u2019t completely fixed to 24 hours\u2014different rhythms can be a bit late or early. So you can expect that early birds have a faster rhythm, while night owls have a slower rhythm.<\/span><\/p>\n

Essentially, the notion that there\u2019s such a thing as a standard circadian rhythm isn\u2019t completely true (but also not completely false). While the sleep schedule most appropriate for you revolves around you going to bed when night falls and rising when the sun does, there\u2019s also a chance that, based on your chronotype, doing precisely this can actually be harmful.<\/span><\/p>\n

What Are the 4 Types of Biological Rhythms?<\/b><\/h2>\n

Now, there are several biological rhythms that govern certain processes in our bodies, all centered on a specific period of time. These four biological rhythms represent the natural cycle in which our body\u2019s chemicals or functions change with time:<\/span><\/p>\n