Jupiterimages/Brand X Pictures/Getty Images. Panic is a natural reaction when you're served with a subpoena, but as far as legal documents are concerned, a subpoena duces tecum is one of the more innocuous ones you can encounter.
Circadian rhythms are biological oscillations that recur with a period of approximately one day. Health issues related to circadian rhythms include jet lag, shift work, seasonal depression, and time-of-day variations in response to medical treatments.
The circadian clock is set by a variety of external factors, but most importantly light during the day and dark at night (also called the light-dark cycle). In order to have healthy circadian rhythms, your circadian clock needs to be set to the right time. The vast majority of your hormones cycle during the day (not just melatonin and cortisol). Not only that, but sensitivity of different types of cells to different hormones can also cycle.