Biological Clocks

Susan Binkley

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9789057025334
• eBook ISBN: 9781000159684
• Topic: Medizin
• Subtopic: Medizinische Theorie, Praxis & Referenz

Biological Clocks introduces the subject of human chronobiology. It describes biological clocks; why we have clocks; how biological clocks relate to sleep disorders, depression, and jet lag; and how the reader can measure his/her own rhythms.

SECTION I: BIOLOGICAL RHYTHMS

Chapter #1: Fooling Around with Time

What is time? What is a rhythm? What rhythms in our environment are important to our biology? What is it all about?

Cycles

The idea of recurring cycles has been considered with respect to all sorts of phenomena—hormone secretion, cancer chemotherapy, growth of tree rings, animal populations, precipitation, crop production, commodity prices, economic recessions and booms, ice ages, tides, sunspots, eclipses, meteor showers, earthquakes, volcanic eruptions, crime, fashion, wars.

The subject of this book, however, is biological timing, the timekeeping in living organisms, in plants, and in animals including people. “Red tides,” for example, recur once a year, producing a brownish red discoloration of the water when the dinoflagellates (Gonyaulax tamarensis, single cell marine microorganisms) which winter on ocean bottoms, rise to the surface and produce a neurotoxin that can kill fish and even the people that eat the fish. Biological cycles may be annual, tidal, lunar, menstrual, and estrous, but the main focus of this book is on daily cycles, of which the most obvious to you is your daily sleep-wake cycle.

Table 1.1 Cycle Sampler¹

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Sunspots	22 years
Declination of the moon	18.6 years
Weather fronts	7 to 8 days
Economy	4 years
Lynx and rabbit abundance	10 years
Bamboo flowering	15–150 years
Cicada emergence	17 years
Chinch bugs and tent caterpillars	9.6 years
Red tides	Once a year

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The Time of Your Life

Probably the most noticeable timing that affects you is the 24 hour alternation of night and day. You have a daily cycle of sleeping and waking that is innate, it does not require light and dark to recur. It may be possible to manipulate the timing of your behavior to maximize the time available, either by altering the quality of use of the time, or by increasing the waking time.

You may think how much time you have may be limited by your lifespan. But look at this differently. Think of the time you have as the time you have awake.

If, for example, you could add 1 hour a day to your awake time, over a lifespan of 70 years, you would gain an astonishing 25,550 hours of time—for work, for leisure activities, for intellectual enrichment, or for rose smelling.

Biological Watch

You may be shocked, and certainly I was shocked when I published my first book, which was about the pineal gland, to learn that the author may not get to choose the book title. So much for the author as God. For a past book, I did manage to fight off Feathered Clocks and Furry Calendars. A reviewer twitted me about the title: “Using The Clockwork Sparrow as a title is a good example of how the author does not understand marketing. It’s a good joke for insiders but has no place in marketing a textbook.” Like most “reviewers,” he didn’t offer an alternative. Heck, I wanted to call that book, The Biological Watch. But my editor was right. More books were probably sold by clockwork sparrows than would have been sold by biological watches.

So, why did I want to call a book The Biological Watch? Living things, possess an internal chronometer. We are like other living things in that we also possess an internal clock. We carry it around with us, and therefore, to me, it seemed appropriate to call it a “biological watch.” The phrase usually used is biological clock. But “clock” makes me think of something mechanical that hangs on a wall.

You might have the idea that I bounded out of my pink bassinet determined to devote my life to studying biological clocks, running around with a magnifying glass, examining ants. I admit that my interest in rhythms and light has been life long. I “spot” an early exposure to the concept of cycles, in a high school science report that I wrote on sunspots—sunspots have cycles of eleven years. In college, I was intrigued by a book about Stonehenge that said the Heelstone points to the midsummer sunrise. I did biology here and there and ended up at the University of Texas in Austin soon after a sniper had aimed his gun from the tower that was the library—proving, if you have any doubts, that libraries are dangerous.

The biology building was under the long-horned shadow of that dark tower. The ecologist already had too many graduate students, and graduate students told me that some other professors didn’t want women students, so why risk being pinched by crayfish? Biological clocks, light, and the pineal gland were amusing. The professor accepted me.² And what else was there to do anyway?

I was not the first to be interested in rhythms. The earliest notice of the rhythm that governs man (and woman!) has been traced back more than 2500 years to Archilochus, a Greek poet. Perhaps the yin-yang nature of a thing—alternation, water and coldness versus fire and hotness and brightness—of the ancient Chinese contained the idea of cycling.³ In 1779, D. C. Hufeland noticed the natural chronology of 24-hour time periods in our lives. J. J. Virey, a French medical student, wrote a thesis in 1814 and used the phrase “horloge vivante,” which means “living clock” for daily rhythms. The first monograph about biological clocks was published by Erwin Bünning in 1958.⁴ I was 12 years old, had never heard of Bünning and was probably reading Bronte’s Jane Eyre or Miss Picker ell Goes to Mars.⁵

Set in Stonehenge

We have to talk a little bit about the motions of the sun and moon.

I will do it here, and for fun, include some speculations about Stonehenge.

Reckoning time has been important to people as far back along that arrow into the past as we are able to peer with our archaeological glasses. My personal favorite in the prehistory of time department is the popular Stonehenge. I have been drawn to Stonehenge the way Neary was obsessed with the Devil’s Tower in Close Encounters of the Third Kind. I always thought those five tones sounded like the first five notes of a song about wishing on stars. By the way, did you know that Stephen Spielberg wrote the book on which the movie is based? But, I digress.

Stonehenge, in case you were sleeping during astroarchaeology class, is a tumble of large stones on Salisbury Plain in southwestern England. I have been to visit it three times. The stones lie on a barren plain—well, now they lie in a patch of mowed grass. Viewed from any side, they appear to stand almost on the line of the horizon. We know little about them, because the architect left no written plans.

It has been great fun to speculate on the meaning of Stonehenge, a sport in which I have participated myself. We can only speculate about the solution to the mystery, but, heck, why not?

What evidence do we have? We know the arrangement of stones and holes. And there is some idea of when parts were constructed—Heel stone and Aubrey holes and Station Stones (c2800 BC), Sarsen Circle and Sarsen Horseshoe (c2100 BC) and after that, the Y and Z holes were dug.⁶

Stonehenge is arranged like a lollipop in which the candy is a series of concentric rings. The outermost ring is an outer bank. Inside that, rings in sequence are a ditch, inner bank, 56 X (Aubrey) holes, 30 Y holes, 29 Z holes, 30 Sarsen Circle of stones, and 5 three-stone trilithons that form a Horseshoe. The outer bank is nearly a hundred meters in diameter; the Sarsen Circle is about 100 feet in diameter.

The “stick”...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Acknowledgments
• I BIOLOGICAL RHYTHMS
• II APPENDICES
• III MEASURE YOUR OWN CIRCADIAN RHYTHM
• About the Author
• Notes and References
• Index