Pollard Willows and Setting Sun by Vincent van Gogh
The Ayurvedic scholars and yoga gurus certainly knew about circadian rhythms. Termed as dinacharya (day routines), ratricharya (nightly routines) and ritucharya (seasonal routines), traditional observances were encouraged in order to maintain the synchronicity of circadian rhythms with time of the day/night and seasonal fluctuations. These practices allowed an individual to tune the circadian rhythm and coordinate it with the earth’s movement (rotation and revolution). The masters were aware that if circadian rhythms went out of sync, disease and imbalances developed. And this is now understood by scientists and health experts who recognize that disharmony in the circadian rhythm contributes to physical, mental, and behavioral problems, including but not limited to mood disorders, heart disease, metabolic syndrome, cancer, and neurodegeneration. Conversely, if we are able to align our circadian rhythm, we can maximize our health span, mental alertness, immunity, awareness, and physical strength.A circadian rhythm is any biological process—physical, mental, or behavioral—that follows a roughly 24-hour cycle, and is modulated primarily by sunlight, darkness, and temperature. Circadian rhythms have been widely observed in humans, animals, plants, and tiny microbes, and primarily influence the sleep-wake cycles, feeding, hormone release, body temperature, and other important bodily functions. Present in all living beings are biological clocks throughout the body that regulate and coordinate our circadian rhythms. Furthermore, there is a "master clock" in the brain that controls all the biological clocks and consequently the circadian rhythms.This master clock (aka the suprachiasmatic nucleus or SCN) is a group of ~20,000 nerve cells in the hypothalamus area of the brain that coordinates all the body clocks and downstream physiological processes. There are certain circadian rhythms in our body that are optimally active during the day and subside when the sun sets. Similarly, there are other circadian rhythms in our body (for example, sleep) that are optimally active during the night and ebb when the sun rises. These biological rhythms represent the optimum performance of different organs at certain times and their relaxation at other times. The circadian rhythms can be easily disrupted by several factors, including but not limited to time zone difference, environmental stress, emotions, and diet. Now that we have some idea of circadian rhythms, it is easy to imagine all those situations where the circadian rhythm can go awry. Specifically, long-distance travelers, pilots, and night shift workers among others will often suffer from circadian rhythm imbalance. I experience similar imbalances when I have to go to India to visit my folks. A difference of 12 hours between the two time zones (Pacific time and India time) disrupts my circadian rhythm causing what we call jet lag. The consequences are disturbed sleep, daytime fatigue, sluggishness, difficulty concentrating, and digestive issues.One of the most important biological processes that is regulated by the circadian rhythm is the sleep response. The SCN, which controls the production and release of melatonin, a hormone that triggers sleep response receives information about the incoming light via the optic nerves (from the eyes to the brain). During sunset when there is more darkness and less light, the SCN triggers the release of melatonin that induces sleep. Come sunrise, there is more light that strikes the optic nerves so melatonin production is halted, thus triggering the wakefulness response. When I fly from California to India, I lose 12 hours of time. So when I wake up at 8:00 am in India, my biological sleep clock thinks it is 8:00 pm of the previous day, thus making me feel groggy, dazed and disoriented. My body's clock will eventually reset itself, but this often takes anywhere from two to seven days, depending on my physical and mental state. It is generally believed that it can take up to one day for each time zone crossed for the body to adjust to the local time. There is a lot of information out there about overcoming jet lag and disturbed sleep cycles and correcting the out of sync circadian rhythm. But in my case, I always turn to yoga. I discussed this issue briefly in my post Yoga in the Skies (Airplane Yoga). In addition to the poses that I described in the post that I do on the plane, after I reach my destination I continue my yoga practice with:
- a few rounds of Sun Salutations
- mild inversions (headstand and supported handstand)
- hip stretches, including High Lunge (Vanarasana), Dropped-Knee Lunge, Warrior series (Virabradrasana), Triangle pose (Trikonasana), Extended Side Angle pose (Utthita Parsvakonasana), and Wide-Angle Seated pose (Upavista Konasana)
- Those who received standard car.
- Those who received standard care plus a four-week yoga intervention. The yoga intervention group (75 mins each yoga session and two sessions per week) received a specialized program (YOCAS) that consisted of pranayama, 18 gentle hatha and restorative yoga asanas, and meditation.
