Circadian Rhythms are our body's natural cycles that control appetite, energy, mood, sleep and libido. When these rhythms are out of sync with nature, we suffer from a Circadian Rhythm Disorder.

"Blessings on him who invented sleep, the cloak that covers all human thoughts, the food that satisfies hunger, the drink that quenches thirst, the fire that warms cold, the cold that moderates heat, and, lastly, the common currency that buys all things, the balance and weight that equalizes the Shepard and the king, the simpleton and the sage." - Miguel de CervantesCirca means "about" or "approximately" and dian meaning "day" in Latin. Broadly it means our daily activity cycle.

Circadian Rhythms are our daily activity cycle that has been inherited from our forefathers and include body's natural cycles that control appetite, energy, mood, sleep and libido. These are delicately balanced cycles can get disturbed and then we suffer from a Circadian Rhythm Disorder. Almost all of us, at some stage in life fall out of balance and suffer from sleep, mood or anxiety disorders.

All living beings have circadian rhythms. Our genes, bacteria, plants, birds all have a certain rhythm that regulate our internal clocks and life itself. No wonder the circadian rhythm is called the 'rhythm of life'. The discovery of circadian rhythms in the early 80's led to a new science called 'chronobiology'.

These body rhythms are tied to the cycles and rhythms of nature. When working properly, our bodies respond to nature’s cues to create their ideal rhythms. For example, when functioning properly, the human circadian rhythm will respond to the morning light of a new day. This light will stimulate the body to produce cortisol, serotonin, other hormones and neurotransmitters that gets a person up and going and causes the blood pressure and body temperature to rise.

At sunset, the body receives another of nature’s cues and responds to dusk and ultimately the night’s darkness. As the sun goes down the body will produce and secrete the hormone melatonin, and blood pressure will drop as the body prepares for and eventually falls off to sleep. This rhythm controls the timing, quantity and quality of the hormones and neurotransmitters the body produces and eventually secretes. Hormones and neurotransmitters are the elements that determine how we feel, our sleep patterns, our appetite, our sex drive and other sleep and mood-related issues. When functioning properly, our circadian rhythms create circadian balance. When out of balance, quantity, quality and timing of hormone and neurotransmitter secretion suffer and our bodies suffer from a circadian rhythm disorder(CRD).

When circadian rhythm disorder affects sleep it is termed circadian rhythm sleep disorder(CRSD).