What are body clocks?
Why do we go to bed at night and wake up in the morning every day? Why is it that we experience jetlag when we visit countries on a different time zone than ours? Why do body temperature and fever tend to rise in the evenings? All these questions can be answered thanks to the discovery, some 30 years ago, of an internal body clock that controls daily changes in many bodily functions: from the alternation between sleep and awake states, body temperature, blood pressure, heart rate and secretion of hormones, to athletic performance, attention and mental abilities. A new branch of science thus was born, called chronobiology (chronos -the Greek word for “time”- ), which studies daily (also known as circadian) rhythms in organisms.
Why are body clocks important?
Research in the field of chronobiology is starting to provide evidence that changes in body clock function can lead to, and can worsen, the consequences of shift work. Shift workers suffer from insomnia, digestive problems, tiredness and irritability amongst other disorders. But what is worse, several studies have demonstrated that long-term shift workers have a significantly increased probability of developing cancer and depression. In addition, changes in body clocks have been found to play a role in several illnesses including Alzheimer’s and Huntington’s disease, metabolic syndrome and cancer. Therefore, body clocks are now being recognised as an important player in human health and disease, and continued research is necessary to further understand the internal clock mechanisms and to develop new therapies to treat clock-related disorders.
How do body clocks work?
In mammals, the principal internal clock is located in the brain, and is key for survival. It is called the “Suprachiasmatic Nucleus”, and it is located in a region called hypothalamus, at the base of the brain. Recent exciting research has found that there is actually more than one biological clock. In addition to the brain Suprachiasmatic Nucleus, clocks have been found all over the body: in the skin, heart, lungs, kidney, fat tissue, etc. So how is this mayhem of clocks controlled? Just like an orchestra, where each instrument produces a melody, each tissue or organ organises its activities in a 24-hour fashion. The key factor in an orchestra is the conductor, who coordinates all the instruments to create a symphony. In a similar way, the brain pacemaker synchronises all the different body clocks, so that they all tick in time.