Circadian Rhythm

Circadian rhythm also known as the sleep/wake cycle is what is scientifically associated with the notion of beauty sleep. Circadian rhythms are a 24 hr time (day/night) specific cycle that oscillates in our bodies at a cellular level. There is a master clock that is located in the brain and there are several clocks in peripheral organs which all work as a team upon receiving signals from the master clock to maintain the health and well-being of our bodies. The master clock mainly responds to light and to other signals such as exercise, food, temperature. Once triggered, the master clock sends the signal to all the peripheral organs to turn on their respective circadian clocks at the cellular level. Any disruption of these signals can affect physiological, metabolically and behavioral processes leading to diseases such as obesity, diabetes, cardiovascular, cancer, aging, etc depending on which peripheral clock is imbalanced.

Effect of irregular sleep patterns on skin metabolism

Under normal environmental conditions, many attributes of the human skin follow a periodicity, they include hydration and trans-epidermal water loss (TEWL), capillary blood flow, sebum production, skin temperature, surface pH, keratinocyte proliferation rates, and even the visibility of facial rhytides. Sleep deprivation disturbs all the above attributes and leads to increased signs of intrinsic skin aging (fine lines, uneven pigmentation, reduced elasticity, dry skin, breakouts), with much slower recovery rates after skin barrier disruption. National Sleep Foundation recommends seven to nine hours of sleep per night for most adults. Less than that can play a role in the development of wrinkles, sagging skin, and dark circles and puffs under the eye.

Some of the benefits proven to attain with rested sleep are:

• Reduction in wrinkles
• Bright eyes
• Well-hydrated skin
• Faster healing
• Less susceptibility to breakouts

Circadian Rhythm and Skin

The skin is the largest peripheral organ and is the outermost protective layer protecting us from the environment. In response to the physiological day/night cycle, the skin has the inherent capacity to function in a circadian rhythmic fashion to protect it from environmental damage in the daytime and heal and repair in the nighttime. During the daytime, when the probability of the skin is to be damaged is more due to its exposure to light or other environmental factors, the protective machinery is set in action to combat the damage. In the nighttime, the healing machinery is put into action to repair the damage caused during the daytime. All these processes function in a circadian fashion, meaning they are time-specific and respond to light. Examples- melatonin, serotonin, vitamin D. Melatonin, and human growth factors are produced in high amounts in the nighttime and these further facilitate the regeneration of the skin cells and repair the damage caused to the skin by UV rays at the cellular level. Melatonin production in the nighttime leads to the production of melatonin receptors which are necessary for vitamin D production during day time. Likewise, vitamin D and serotonin are day hormones and are produced in response to light during the daytime to protect the skin from UV rays along with their important roles in other biological processes.

By sleeping at the right times, we enable this time-specific machinery such as melatonin and human growth factor, vitamin D, etc to perform their functions in the body. For example, lack of sleep results in lowering the melatonin level in the body. The body responds to this by signaling its stress hormone cortisol to be produced which responds by causing inflammation in the cells. There is a whole negative set of cascade reactions that go into motion. A repeated irregularity in sleep patterns affects not only skin health but overall health as well.

What is the right time to go to bed to achieve Beauty sleep

Melatonin secretions start around 9.00 PM and stop at 7.30 AM in the body and hence it is recommended that going to bed around 9 to 10.00 PM would give maximum beauty effect. Normally sleep has two phases- NREM and REM phases. The NREM phase has three stages and begins from the time we close our eyes to try to sleep. This is followed by the REM phase. The cycles of NREM and REM repeat all through the night with each phase lasting between 90 to 120 min. Each of these phases has a distinct physiologic effect on the body. It is during one of the stages of the NREM phase that the body including the skin has the ability to repair and rejuvenate. Going to bed early will give the body enough time to repair without any negative reactions.

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Check out our next article on the skin type and the basic skincare routines recommended.

“Quality over quantity- make sure you are not just getting the number of hours to sleep but quality sleep and wake up rested, happy and beautiful with a smile on your face”