New insights into circadian aspects of health and disease.

ABSTRACT

Early awakening and early to bed as well as good conduct, thought, diet, interpersonal dealings and physical activity have been suggested for healthy life in Ayurveda. Circadian rhythms, coordinated in part by the parietal hypothalamic-pituitary and adrenal mechanisms, have been reported in almost all variables examined thus far, including the circulation. It is possible that all metabolic functions undergo circadian rhythms. It remains to be explored whether these rhythms may be optimized by Ayurvedic practices. The onsets of myocardial ischemia, unstable angina, acute myocardial infarction, sudden cardiac death, and strokes have been reported to exhibit a circadian variation, with increased frequency in the second quarter of the day. An increased physical and mental load caused by an attempt to prepare for the day may be important in triggering acute cardiovascular events. Depending on their timing, meditation (Ayurvedic practice), n-3 fatty acids, coenzyme Q10, beta-blockers and estrogens may have beneficial effects, whereas progestins and mental load may have adverse effects on heart rate and blood pressure variability, which may be expressed by different circadian patterns. Around the clock serial recordings of blood pressure and heart rate during usual activities and lifestyles may be recorded and may be analyzed by computer-implemented curve fitting to assess the about 24-hour (circadian) variation, among other rhythmic, chaotic, and trend components of the time structure (chronome) of these variables. The new disease risk syndrome circadian hyper-amplitude-tension (CHAT), a condition characterized by an excessive circadian amplitude of blood pressure, cannot be ascertained on the basis of single casual blood pressure measurements. The International Chronome Ecological Study of Heart Rate (and blood pressure) Variability in various ethnic groups aims at collecting further evidence regarding the role of blood pressure and heart rate variability in the pathogenesis of cardiovascular events, while also examining any role played by ethnicity and lifestyle-associated factors.