Sleep 3
Your body temperature (in degrees Fahrenheit) changes throughout the day and is another critical part of your circadian rhythm. You are generally the warmest around 9 p.m. and then, as your body begins to cool, you go to sleep. Your body is at its coldest in the morning as you wake. Image courtesy of Cdn.lifehack.org/wp-content/uploads/2017/11/08220605/temperature-during-the-day.png.