From research in Ayurveda:
“Circadian rhythm is the cyclical 24-hour period of human biological activity. Within the circadian (24-hour) cycle, a person usually sleeps approximately 8 hours and stays awake for 16 hours. During the wakeful hours, mental and physical functions are most active and tissue cell growth increases. During sleep, voluntary muscle activities nearly disappear and there is a decrease in metabolic rate, respiration, heart rate, body temperature, and blood pressure. InAyurveda, this concept is based on three Doshas- Vata, Pitta, Kapha – which predominantly govern our daily routine life. These Doshas maintain the integrity of our body by creating, assimilating & diffusing strength. In this article, efforts will be made to correlate the Doshic influence which affects the human body.”
Source: Research paper by Poonam Choudhary, Reetu Sharma, Ranjana Pande and Sushila Sharma