Circadian rhythms are regular changes in biology or behavior that occur in a 24-hour cycle. In humans, for example, blood pressure and body temperature change in a regular way throughout each 24-hour day. Animals may eat and drink at certain times of day as well. Humans have daily cycles of behavior, too. Most people start to get sleepy after dark and have a hard time sleeping when it is light outside. In many species, including humans, circadian rhythms are controlled by a tiny structure called the biological clock . This structure is located in a gland at the base of the brain. The biological clock sends signals to the body. The signals cause regular changes in behavior and body processes. The amount of light entering the eyes helps control the biological clock. The clock causes changes that repeat every 24 hours.
Joe started work at 8 a.m. After a long day at work he spends time with his family and is usually in bed by 10p.m Beth works night shift. She starts work at 11 p.m. She gets of at 7 a.m after having breakfast and getting her children off to school she gets some things done around the house and is usually in bed by 2.p.m.
Who is working with their bodies natural schedule?