Does Circadian Rhythm matter?

We all have internal clocks that regulate processes to enable life such as metabolism, immune system, storing energy, transporting oxygen, maintaining gut health, body temperature, release of hormones and many more. This internal clock is referred to as Circadian Rhythm. Circadian Rhythm is regulated by clock genes that make the body tick like a well oiled machine. We all know that there is something in our body that regulates the cycle of living creatures be it mammals, algae or human beings. There are millions of biological functions that strive to accomplish three major functions- eat/drink, sleep & reproduce.

Circadian Rhythm is made up of a set of clocks & a master-clock known as Suprachiasmatic nucleus(SCN). SCN is located in the hypothalamus, a part of the brain responsible for regulating stress, reproduction & growth hormones. In a sense, it also impacts our sleep hormones-Melatonin. SCN is composed of 20,000 cells located just above the intersection of our optic nerves. Here it directly receives signals from special cells retina that respond directly to light exposure. These special cells receptors also known as melanopsin receptors are stimulated by blue light, then green light & finally red light. Circadian clock is present in every cell of your body & as such effects of Circadian Rhythm are found not only at organ level but also on cellular level. Physiological changes as described in the below figure occur as a result of genes producing protein that stimulates internal biological clocks

Your circadian rhythm responds to light- it wakes you up & it also puts you to sleep by triggering chemical reactions inside the brain. We have clock genes in every hormone- they switch on & off on predictable events, switching on & off production of proteins that perform essential functions inside our cells. Around 20% of genes turn on & off during a 24 hour cycle.

Circadian rhythm is a discreet mechanism that does not like to be interrupted. When interrupted, it let you know in a number of ways that it is doing to impact quality of life & various important aspects of biological processes. Specifically, it impacts our digestion, body temperature & release of hormones. Some of the ways it impact your life include:

  1. Sleep: Either you would sleep a lot or may face difficulty in falling asleep
  2. Weight: Not able to lose weight
  3. Low energy & dependence on caffeinated products
  4. Late night food cravings & digestion related problems
  5. Weak immune system, frequent illness.

These are some of common symptoms telling that your circadian rhythm is disrupted. Sleeping at irregular times, eating late & using devices do not go well with your body. Let me explain this in respect of your digestion. Your digestion system is prime /refreshed & is ready to take food during the first half of the day. Enzymes, hormones & secretion of gastric juices that are responsible for breakdown, distribution & storing of fuel( from food) generally takes place in afternoon & evening & by night, it ceased to operate, However if you ignore this & continue to eat specifically during evening & night, you disrupt its plan to repair & renew everything for having everything in working order the next day. Same thing applies to your brain. If you play with your sleep schedule or have deficient sleep, then you interrupt the process.Sleep disturbances have a detrimental impact on the individual’s health, including effects on the cardiovascular system, the negative effects on mental health.

Similarly if you eat late at night, exercise after work & have breakfast at irregular times, you are disrupting the circadian cycle.

Disrupting your circadian rhythm regularly or keeping it off the shelf both on a short or long term basis is associated with serious chronic & preventable diseases. Shift workers & travellers who regularly keep disrupting their circadian cycles are exposed to higher risk of obesity, type 2 diabetes ,various other metabolic related issues, coronary heart disease & hypertension. As mentioned above, there are a lot of frequent disturbances to biological clocks in the modern world such as frequent travelling across different time zones causing misalignment of our clock & jet lag. Such disturbances are more pronounced among shift workers & modern world professionals where they work for a longer period of time/ late nights & get up late or where night shifts are compulsory.

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