Introducing Biological Rhythms
25 April 2007A Primer on the Temporal Organization of Life, with Implications for health, Society, Reproduction and the Natural Environment.
Introducing Biological Rhythms by Willard L Koukkari & Robert B Sothern
see
Chronobiology for an early review
“Be ruled by Time, the wisest couselor of all.”
– Plutarch
“Dost thou love life? Then do not squander time, for that’s the stuff life is made of.”
– Benjamin Franklin
“To everything there is a season and a time to every purpose under heaven: a time to be born and a time to die: a time to plant and a time to pluck up that which is planted; a time to kill and a time to heal; a time to break down and a time to build up.”
– Ecclesiastes 3:2-3
Ch 1 - The Study of Biological Rhythms
Ch 2 - General Features of Rhythms: Terminology and Characteristics
p19
“What is time, then? If nobody asks me, I know; if I have to explain it to someone who has asked me, I do not know.”
– St. Augustine
p29
“… a special term called acrophase is used to designate the distance in time of the peak (=acro) phase of the mathematical curve from an arbitrary reference point. Similarly, the lowest point on the fitted cosine is called the bathyphase.”
p34
“Results from studies… identified the hypothalamus of the brain as the location of the primary oscillator.”
p35
“Anatomically, [the suprachiasmatic nucleus (SCN)] is located above the optic chiasm, where the two optic nerves cross, and includes two clumps of nuclei, each containing about 10, 000 neurons.”
p36
“… oscillations occur throughout the body, but to delineate them form those of the SCN, they are referred to as peripheral oscillations, and the tissues where they occur as peripheral tissues.”
“Peripheral oscillations may differ from those of the SCN in a number of ways, including the phase that can be delayed by about 4 h from the SCN.”
“The daily light-dark (LD) cycle serves as a major synchronizer of circadian rhythms, which means that organisms must have photoreceptors.”
p37
“melanopsin is an opsin-like protein…”
“Non-image-forming photoreception mediated by melanopsin is now recognized as a major component in the synchronization of circadian clocks.”
p37-8
“… it has been known that photic (light) information is conveyed from the eyes to the hypothalamus via the retinohypothalamic tract (RHT) where its neural projections terminate in the bilaterally paired SCN.”
p49
[phototropism]
“growth movements of plants directed toward… light.”
|
TABLE 2.5 |
|
| Due to the gratiation effect of the Moon since its formation 4.45 billion years ago (bya), the Earth’s day has bee slowly becoming larger* | |
| Time Scale | Duration of one rotation of hte earth (h) |
| 4.5 bya | 6.0 |
| 4.4 bya | 10.0 |
| 4.0 bya | 13.5 |
| 900 mya | 18.17 |
| 400 mya | < 22 |
| 245 mya | 22.75 |
| 100 mya | 23.5 |
| today | 24.0 |
| 225 my hence | 25.0 |
| * As the Moon has slowly moved away from Earth, its effect on the Earth’s day length has also been slowing down. One secon dis added to our day every 62, 500 years. | |
p56
“There is a genetically determined, endogenous basis for biological rhythms in all living organisms. Periods are grouped into three main categories: ultradian ((< 20 h), circadian (20 - 28 h), and infradian (> 28 h)… the SCN and pineal are examples of primary circadian clocks located in the brain.”
Ch 3 - Physical and Biological Time
p67
“… the Earth make one complete rotation on its axis n about 23 h 56 min.”
p69
“Not only is the Earth rotating, it is revolving around the Sun. As a result, the location of the Earth relative to the Sun has changed by about one degree. The span of time of 23 h and 56 min is called the sidereal day (=360 degrees), while our clocks are based upon the solar day (360 + 1 = 361 degree). of 24 h.”
“The seasons of the year… provide time cues via photoperiodism…”
Linnaeus Flower Clock
link to large Linnaeus’ Flower Clock
p93
“The timing systems in both prokaryotes (cyanobacteria) and eukaryotes (fungi, plants, and animals) have a number of key molecular components. These include, among others, clock genes, cycling proteins, and photoreceptors. Photoreceptors are part of an input pathway that receives and transmits signals from external environmental synchronizers to a central clock that generates rhythmicity. In turn, an output pathway transmits temporal signals from the clock to biological variables that that oscillate. These oscillations are the overt rhythms of variable such as activity cycles, leaf movements, spore formation, and enzyme activity.”
p95
“Some scientists contend that early building blocks or biological molecules may have been deposited on Earth from meteorites and comets originating elsewhere in the galaxy.”
p102
“The rotations and revolutions of the Earth account for the natural synchronization of circadian and circannual rhythms, as well as for the changes in duration and timing of light and dark spans in photoperiodism. Two types or groups of clocks are paramount in the study of biological rhythms… One group includes the mechanical, electrical, and atomic clocks of society… The other… is biological, present in the cells of organisms and having a mechanism that is based upon feedback loops, genes, and cycling proteins.”
Ch 4 - Photoperiodism
p111
“Photoperiodism can be defined as a response of an organism to the timing and duration of light and dark.”
p129-30
“In locations where changes in day length are more pronounced (e.g. higher latitudes) the peak in human conception was found to coincide with the vernal equinox.”
[most notably with the full moon - sounds a little like Easter, no?]
| TABLE 4.8 | |
|---|---|
| Examples of human behaviors or disorders that have ben found to correlate with the time of year and photoperiodism | |
|
Variable
|
Location of peak(s)
|
| Alcoholism | Spring |
| Bipolar and shizoaffective illness, violent episodes | Jun & Dec (Israel) |
| Chronic fatigue syndrome | Winter worsening |
| Depression (rating) | Winter months |
| Depression (hospitalizations) | Spring & Autumn |
| Eating disorders | Winter more severe |
| Acts of hostility* and individual violent crimes** | Summer in N&S hemispheres |
| Mania |
Spring-Summer |
| Menarche (first menstruation) | Dec-Jan & Aug-Sep |
| Mood | Winter worsening |
| Seasonal Affective Disorder (SAD) | Winter |
| Schizophrenia (hospitalizations) | Jul-Aug (UK) |
| Sexual conception | increases near Vernal Equinox |
| Sleep problems | Winter |
| Suicide | Spring |
| * opening dates of wars in both hemispheres. Onset of wars near the equator showed a near-constant montly rate throughout the year. | |
| ** Includes offenses against the human body, sex offenses, forcible rape, and aggravated assault. | |
p132
“The normal development, reproduction, and activities of organisms are often dependent upon the duration and timing of light and dark spans, which in nature are associated with the seasons. This process is called photoperiodism, a complex and diverse process that is a basic principle of biology and is intrinsic in the temporal organization of life.”
Ch 5 - Biological Osciallations and Timers; Models and Mechanisms
p138
“Within the realm of life, there is a structural organization, a hierarchy of components, extending from subatomic particles (e.g. electrons, protons) to organisms and ecosystems. how these components function (physiology) individually and in networks, depends not only upon the presence of the correct components and where they occur, but when. individual components and site of action are represented by structural units, while ‘when’ represents the temporal organization of life and the measurable unit known as time.”
Ch 6 - Tidal and Lunar Rhythms
p207
“… cycles of the tide (12.4 h), the lunar day (24.8 h), and the lunar month (29.5 days). Biological variables that have these approximate periods are often referred to as having circatidal (12.4 h), circalunidian (24.8 h), and circalunar (29.5 days) rhythms.”
p208
“the mean solar day is 24 h, but the lunar day is 24.8 h, which explains why the Moon appears to rise an average of 50-51 minutes later each day.”
p209
“Overall, the quality of full moonlight appears to be quite close to that experienced just after sunset, a significant feature since photoreceptors of oscillators, such as the phytochromes, cryptochromes, and other pigments, depend not only upon the total energy of the visible spectrum, but rather upon the energy of specific wavelengths. Furthermore, it is the light present at dawn and dusk, not the changes in irradiance during day and night that organisms utilize for circadian photoentrainment.”
| Table 6.6 | ||
|---|---|---|
| Variables in humans reported to vary with the phases of the Moon | ||
|
Variable |
Moon Phase |
Behaviour |
| births | last quarter to new Moon | increased births |
| accidental poisonings | near new Moon | increased for women |
| meal and alcohol intake | near full Moon | meal size increases, alcohol intake decreases |
| urinary retention | near new Moon | increased retention |
| psychopathology in schizophrenia | near full Moon | deterioration |
| aggressive behaviour | full moon | increased aggression |
| psychiatric admissions | first quarter | increased admissions |
| myocardial infarction | near new Moon | maximal incidence |
| animal bites | near full Moon | increased incidence |
| gout | near new and full Moons | highest peaks |
p209
“Unlike the situation for terrestrial plants, the response of various animals to moonlight is more definite.”
p210-1
“A global view of the Earth reveals two hight tides and two low tides occurring simultaneously. one high tide occurs approximately in line with the Moon overhead, and the other on the opposite side of the Earth. Similarly, the low tides are present also at these times, but located 90 degrees from the high tides.
Tides
p212-3
“While the gravitational force accounts for the bulge on the side that faces the Moon, a centrifugal force dominates in producing the bulge on the opposite side.”
p213-4
“… the path followed by the moon as it completes one full revolution of 27.3 days (= 1 tropical month) around the Earth varies from 28 degrees 30′ north latitude to 28 degrees 30′ south latitude.”
spring and neap tides
p214
“During the new Moon phase… the gravitational pull of the Sun combines with the gravitational pull of the Moon to cause much higher tides… called spring tides when the gravitational pull of the Sun is at right angles to the gravitational pull of the moon (near the first and third quarter phases of the Moon), the high tides are lower than normal and the low tides are higher than normal. These conditions are referred to as Neap Tides. The duration between two successive neap tides is about 14.8 days, as is the duration between two spring tides.”
p220-1
“for many marine invertebrates, especially those found within or near the tropics, rhythms in reproductive events such as mating, egg, and sperm formation, spawning and hatching (release of larvae) have periods and/or phases that appear to be associated with the phases of the Moon. The events may occur only fortnightly, monthly, or just once a year.”
p222
“Often the fortnightly and monthly cycles may be liked to an annual and/or photoperiodic cycle, that may be biologically linked or mathematically correlated to the other two cycles.”
p224
“Recurring changes in the color of cells, tissues, and organs are found in diverse groups of organisms and often associated with the time-dependent physiological processes.”
p227
“The Swedish Chemist, Svante Arrhenius, reported that menstruation, as well as epileptic seizures exhibited a periodicity between 25.9 and 27.9 days… results from a number of more recent studies indicate that the mean period of the menstrual cycle is about 29.5 days.”
p228
“Variables in seeds, stems, and leaves have been associated with lunar cycles. Results from studies of the daily imbibition (absorption( of water by bean seeds have shown a circannual rhythm, as well as a circaseptan rhythm with a phase relationship to the lunar cycle - peaks preceded each lunar phase and imbibition was greatest from just before full Moon through the last quarter.”
[n.b. growing with light vs growing with water]
p229
“Another lunar association has been reported for elongation of stems (cm/day)… where periods of 14.7 days and 29.5 days were found…”
“The most common external cycles associated with our environment, and thereby possibly serving as synchronizers for biological rhythms, are the 12.4-h tide, the 24-h solar day, the 24-8 lunar day, the 29.5-day lunar month, and the year. There are other environmental cycles…”
Ch 7 - Sexuality and Reproduction
p237
“… sexuality and reproduction are part of all four integrating disciples of biology: evolution, genetics, development, and biological rhythms…”
p268
“One of the many interesting features of the menstrual cycle s social synchronization, whereby the phases of the rhythms of several individuals become synchronized… Apparently, the synchronization is dependent upon socialization, and indications re that the causal agent [are]… pheromones.”
“Phases within the menstrual cycle have been closely associated with times of sexuality, or lack thereof, which in turn can be strongly linked to the rhythmic levels of biological molecules, as well as to society, culture, and religion.”
p272
“… human males also have a ‘gonadal’ rhythmicity ranging from ultradian to circadian to infradian in many primary and secondary aspects related to their sexuality.”
p284
“Sexuality and reproduction have a temporal organization, with variables that span the ultradian, circadian, and infradian domains of biological rhythms. These oscillations are present throughout a genetically-based structural hierarchy that extends from organelles to ecosystems.”
Ch 9 - Veterinary Medicine
Ch 10 - Society
p380
“Social Synchronization refers to a behavioral rhythm being regulated by an external source generated by another individual or some other social condition. It occurs not only in humans, but many other species, as well…”
p401
“Daily exogenous cycles of feeding may synchronize circadian rhythms.”
p409
“The effects that light pollution has on humans are often mediated by the hormone melatonin [MLT]… In addition to synchronizing circadian clocks, MLT has strong antioxidant properties. MLT has also been found in plants.”
p410
“Exposure to artificial light of moderate intensity (180 lux) during the middle of the night has been shown to phase-shift human circadian rhythms of ML and cortisol levels, which shows that the circadian entrainment mechanism of humans, like those of other mammals, is sensitive to low levels of light.”
p410-1
“Light thus has the ability to ‘act like a drug’ and, as such, has become a public health issue. Areas possibly affected by changes in melatonin production include endocrine functions associated with puberty, psychiatric illness, stress-related disorders, immune responses and carcinogenesis.”
p411
“While prior human exposure to artificial light at night came from sources such as flames of an orange red fire or the yellow light of candles, gas lamps or incandescent bulbs, today’s lights emit more blue light…”
better lighting practices
* full-spectrum lighting during the daytime indoors
* non-blue lighting at night, indoor & outdoor
* night workers should wear orange lens glasses when outside in the AM (called Blue Blockers, they prevent MLT suppression)
p413
[the authors dismiss an early theory of chronobiology]
the human body undergoes three cycles
23-day cycle of the physical
28-day cycle of the emotional
33-day cycle of the intellectual
“The cycles repeat themselves throughout one’s lifetime and are only all back at the same starting point every 58 years plus 67 or 68 days. (23 days x 28 days x 33 days = 21, 522 days)”
“However, the 23- and 28-day rhythms are considered more important than the 33-day intellectual cycle, and they start a new biorhythmic year with a simultaneous upswing every 644 days (1 year, 9 months).”
see Ayurveda and the 3 embryonic membranes
and Gestation Time and Health
Ch 11 - Clinical Medicine
p427
“… virtually every body function in humans has been shown to display a circadian and/or other rhythm in healthy individuals which persists into old age, often with a reduction in amplitude.”
p433
“The many naturally occurring daily and other body rhythms that have evolved as adjustments to environmental changes due to the solar day and year and lunar month have a regulating influence on the ‘normal’ functioning of the body’s many processes. Humans and other animals have genetically based biological clocks that are present in individual cells, resulting in semi-autonomous oscillators…”
“[A 19th C German study found] a predictable range [of body temperature] that extended from a low of 36.2 degrees C between 02:00 h and 08:00 h to a peak of 37.5 degrees C between 16:00 h and 2100 h…”
p445
“… growth of human head and body hair was reported to increase through the summer months, reaching a maximum rate in September, and then decreasing to a minimum in January.” [n.b. presumably in the Northern hemisphere]
p452
“The annual pattern of depression and suicidal behavior generally shows a major peak in the spring, with sometimes a secondary peak in the late fall.”
p456
“The daily external environmental cycle of a light span followed by a dark span synchronizes circadian rhythms. The cycle provides a signal sent to the pineal gland, which is located near the hypothalamus in the brain of humans and other animals, to produce melatonin during darkness and to inhibit its production during light.”
Ch 12 - Autorhythmometry
p526
quoting German physician CW Hufeland
“That period of twenty-four hours, formed by the regular revolution of our earth, in which all its inhabitants partake, is particularly distinguished in the physical oeconomy of man… it is, as it were the unity of our natural chronology.”
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