Sleep and the Ayurvedic Clock

The Ayurvedic Clock

Sleep is one of the most fundamental aspects of health, yet it is often neglected in the fast-paced work-life balance that dominates our culture today. Nearly 40% of American adults report having insufficient sleep, defined as less than 7 hours of sleep per night (CDC). It is no mystery to modern scientists that insufficient sleep can have an assortment of adverse effects, ranging from decreased energy and productivity to increased risk of cognitive dysfunction, depression, and accidents (PubMed).

But Ayurvedic practitioners have long since deciphered the ideal adult sleep schedule, supported by current scientific consensus on the circadian rhythm and sleep-wake cycles. The Ayurvedic clock divides the day into six energy-aligned zones, each lasting four hours:

Vata

Vata is a transcendent and spiritual time primed for wakefulness and meditation. Your body is at its weakest during this time, so you should avoid intense exercise and focus on less physically stressful activities. This phase lasts from 2 to 6 AM in the morning and 2 to 6 PM in the evening. Misalignment may manifest in issues such as constipation, bloating, dry skin, arthritis, anxiety, and poor circulation.

Kapha

Kapha is the slow, steady energetic state aligned with earthiness and stability, perfect for exercise and a balanced meal. This phase lasts from 6 to 10 AM in the morning and 6 to 10 PM in the evening. Ideally, exercise should occur between 6 and 8 AM, with breakfast afterward. However, if you miss the chance for physical activity in the morning, make sure to exercise no later than 7 PM. During kapha, it is important to avoid stressing the digestive system with excessively sweet, salty, or oily foods. Misalignment may manifest as asthma, diabetes, slow digestion, and metabolic issues.

Pitta

Pitta is the strong, fiery energy state during which your metabolism and digestion are most vigorous. A recent study has shown that body temperature rises throughout the morning and peaks during noontime, supporting Ayurvedic theory of the body’s robust vitality during pitta. This phase lasts from 10 AM to 2 PM during the day and 10 PM to 2 AM during the night. It is recommended that you consume your largest meal of the day during this phase of the daytime. During the evening, you should go to bed to avoid the “second wind” of energy that you might feel around 10 PM, which may cause you to stay up and miss the most restorative hours of sleep. Misalignment may manifest as acidity, body heat, skin rashes, and ulcers.

Circadian Rhythms and Ayurvedic Wisdom

The ancient Ayurvedic chronograph aligns with the body’s natural inclinations towards light and energy. The circadian rhythm, our body’s biological clock, is tailored to respond to light and its absence, priming us to sleep during the darkest hours of night and rise during the early hours of dawn. Lack of light stimulates the pineal glands in our brains to release the biological precursors of melatonin, which signals the hypothalamus to slow the body’s activities in preparation for sleep. Exposure to blue light, particularly from phones and other electronics, impedes the secretion of melatonin, which can shift the circadian rhythm and hinder sleep (Harvard Health).

Aligning our sleep-wake cycles with the body’s natural hormones as prescribed by the Ayurvedic clock allows us to achieve the most restful sleep between 10 PM and 6 AM. Deviating from these naturally-occurring biological rhythms can have dysfunctional implications for many biological markers, including plasma cortisol, melatonin, and minimum body temperature (Cleveland Clinic). Increases in cortisol can lead to digestive imbalance and overeating, while lack of melatonin may interfere with our ability to fall and stay asleep.

Missing the most restorative periods of sleep by not sleeping on time or for long enough, often through activities like purposely staying up or running on a disrupted sleep cycle, can impair the body’s long-term ability to heal itself and maintain optimal function. Each sleep “cycle” is approximately 90-120 minutes long, with the third stage of non-REM sleep being the deepest and most restorative stage, involved with strengthening immune function, repairing muscle and bone, and regrowing tissue (NIH). These restful stages shorten closer to the morning, so Ayurveda advises that adults sleep during the nighttime pitta and vata stages to reap their benefits, waking just before 6 AM to tap into the clear, serene qualities of vata.

Heart Rate Variability and Sleep Quality

One way to assess sleep quality (and overall health) is by measuring heart rate variability (HRV). Heart rate variability is a measure of the variation in timing between heartbeats, and is often used to evaluate vagal tone, or the activity of the vagus nerve (Cleveland Clinic). The vagus nerve is a fundamental component of the parasympathetic branch of the autonomic nervous system, which regulates a wide range of body functions like breathing, digestion, and blood pressure. While the parasympathetic nervous system is involved with “rest-and-digest” functions like slowing heart rate, increasing blood circulation to the digestive tract, and relaxing muscles, the sympathetic nervous system is implicated in the “fight-or-flight” response, responsible for increasing glucose availability in the bloodstream, elevating heart rate, and contracting muscles (NIH).

Higher heart rate variability is associated with positive health outcomes, indicating that the heart is able to adapt to the body’s various needs and adjust in the context of different respiratory patterns (such as during wakefulness or sleep). A normal HRV can vary from below 20 milliseconds to above 200 milliseconds and varies significantly from person to person, so your own HRV should only be compared to your baseline. For most healthy adults, however, a normal HRV will be somewhere between 19 and 75 milliseconds (WebMD). Athletes and more regularly active individuals may have an even higher HRV.

While echocardiograms will always give the most accurate HRV data, Apple Watches also display relatively accurate measures of HRV. If your Apple Watch is synced to your Health app, navigate to the app and select Browse > Heart > Heart Rate Variability. Alternatively, you can use an Oura Ring to obtain the same data (which may be more comfortable to wear during sleep).

Tips for Better Sleep

Improving sleep quality can have vast effects on one’s overall health, including improved heart rate variability, increased energy, and more consistent appetite. In order to align your body with the Ayurvedic clock and enjoy the vitality that follows, make sure to:

• Turn off your devices at least thirty minutes before you sleep. Melatonin does not take effect immediately—it needs time to accumulate in the bloodstream! Focus on a short bedtime routine to help soothe your mind in preparation for sleep, and keep bright lights to a minimum.
• Practice mindful meditation. In addition to helping reduce chronic pain and anxiety, meditation is known to promote relaxation and higher-quality sleep. Take ten minutes out of your nighttime routine to close your eyes and follow along with a meditation of your choice, or simply tune in to your body and surroundings.
• Avoid heavy foods before bed. Hunger can obstruct sleep, but so can an overly heavy meal. Avoid stressing your digestive system with anything too filling or processed for two to three hours before you go to sleep.

References:

1. FastStats: Sleep in Adults – CDC
2. Neurocognitive Consequences of Sleep Deprivation – PubMed
3. The Ayurveda Clock Explained: How To Align Your Schedule For Optimal Health
4. Blue light has a dark side – Harvard Health
5. Circadian Rhythm: What It Is, How It Works & What Affects It – Cleveland Clinic
6. Physiology, Sleep Stages – StatPearls – NCBI Bookshelf – NIH
7. Heart Rate Variability (HRV): What It Is and How You Can Track It – Cleveland Clinic
8. Anatomy, Autonomic Nervous System – StatPearls – NCBI Bookshelf – NIH
9. Heart Rate Variability: Influencing Factors & How to Monitor