A Brief History

Chronobiology dates back to 1729 when the French astronomer Jean Jacques d’Ortous de Mairan noticed that the leaf movements of the mimosa plant had a clear day-night cycle. It wasn’t until the early 1880s that the concept of an inherited rhythm—rather than a rhythm that only responds to external stimuli—was theorized. This theory, proposed by Charles Darwin, laid the foundation for many studies to come. Chronobiology began to flourish in the 1950s. The father of American chronobiology, Franz Halberg, coined the term “circadian” to describe an innate biological rhythm that lasted approximately a day. Colin Pittenrigh, Gustav Kramer, Michael Menaker, Alfred J. Lewy and many others expanded the field to make groundbreaking discoveries that have changed the way we practice modern medicine.

 

What is Chronobiology?

The field of chronobiology deals with the interplay of external and internal timekeepers with endogenous processes, as well as the impact of this relationship on our well-being. The principle is that all processes in our organism have their own rhythm, including each individual human organ. These timekeepers direct our genetically-determined base rhythm and regulate all physical, spiritual and emotional functions without us being aware of it. The better we can align ourselves with this rhythm, the more usefulness can be gleaned from it. It is crucial to know that everything has its proper timing.

 

For example, why do we have more energy in the morning than in the afternoon? Why are our bodies able to bear pain better between 8 and 9 a.m.? Why do memory performance and the ability to learn peak between 3 and 4 p.m.? Chronobiology provides answers to these and many more questions.

 

The Branches of Chronobiology

 

Chronophysiology

Chronophysiology is the discipline of chronobiology that studies the timed procedure of physiological processes. For instance, which system produces the hormone melatonin? When is melatonin released and when is it at its highest concentration within the body? What influences the release of melatonin? These are the types of questions chronophysiology seeks to answer.

 

Chronopathology

Chronopathology studies the disrupted timing of vital processes. This discipline aims at identifying deviations from normal rhythms.

 

Chronopharmacology

Chronopharmacology, the most well known branch of chronobiology, studies the inner clock and its effect on medicinal therapies and vice versa. The correct timing of a medication, supplement, or therapy can increase its effectiveness while minimizing adverse side effects.

 

The Rhythms of Chronobiology

There are three primary rhythms in chronobiology. An ultradian rhythm is a cycle lasting under a day. Hunger, blood circulation and sleep cycles are all examples of ultradian rhythms. The most studied rhythm, the circadian rhythm, is a cycle of approximately 24-hours. The sleep-wake cycle is the most commonly studied circadian rhythm. The final rhythm is called an infradian rhythm. An infradian rhythm is a cycle lasting more than a day, such as the female menstrual cycle or the phases of the moon.

 

 

Bullet points

• Chronobiology dates back to 1729 when the French astronomer Jean Jacques d’Ortous de Mairan noticed that the leaf movements of the mimosa plant had a clear day-night cycle
• Chronobiology is the study of innate biological rhythms and how they are influenced by external factors
• All organisms have their own rhythm, including each individual organs
• Internal and external timekeepers direct our genetically-determined base rhythm
• Chronophysiology: studies the timed procedure of physiological processes
• Chronopathology: studies how the interrupted timing of vital processes
• Chronopharmacology: studies the inner clock and its effect on medicinal therapies and vice versa
• Ultradian rhythm: A rhythm lasting under a day
• Circadian rhythm: A rhythm lasting approximately 24-hours
• Infradian rhythm: A rhythm lasting longer than a day