Estimated Reading Time: 10–12 minutes

What You Will Learn

• How modern circadian science explains biological timing across the brain and body.

• What Dr. Reem Al Nuaimi’s The Biological Clock proposes about organs, emotions, and daily rhythms.

• Where her holistic framework overlaps with established chronobiology and where it represents a traditional or interpretive model.

• Why peripheral organs genuinely contain molecular clocks without each organ having one scientifically established two-hour “peak.”

• How light, sleep, food timing, activity, stress, and social schedules interact with biological rhythms.

• How to observe your own patterns without turning every fluctuation in energy or mood into a diagnosis.

• Practical ways to support circadian health while keeping flexibility, culture, and individual differences in view.

Introduction: Time Exists Inside the Body Too

We usually experience time as something outside us. It appears on clocks, calendars, alarms, work schedules, prayer times, meal times, and deadlines. Yet biology also contains its own forms of timing. Sleepiness rises and falls, body temperature changes across the day, hormones are secreted rhythmically, metabolism varies with biological time, and many cells contain molecular mechanisms that oscillate across roughly twenty-four hours.

Dr. Reem Al Nuaimi’s The Biological Clock approaches this idea through a broader holistic framework. Rather than treating biological timing purely as a laboratory concept, the book connects bodily rhythms with organs, daily behavior, emotions, and the experience of living in time. Its perspective draws heavily on traditional ideas about organ timing while presenting them alongside a broader invitation to observe how the body changes throughout the day.

That combination makes the book thought-provoking, but it also makes scientific distinctions especially important. Modern chronobiology strongly supports the existence of central and peripheral biological clocks, yet it does not validate every traditional correspondence between a specific organ, two-hour period, emotion, food, or psychological state. The most useful way to read the book is therefore not to collapse traditional medicine and biomedical science into one system, but to examine where they overlap, where they differ, and what practical questions each can inspire.

The Biological Clock in Modern Science

Circadian rhythms are biological processes that recur over approximately twenty-four hours. In humans, a central circadian pacemaker is located in the suprachiasmatic nucleus, or SCN, in the hypothalamus. The SCN receives information about environmental light through specialized retinal pathways and helps synchronize rhythms in sleep and wakefulness, melatonin production, body temperature, hormonal secretion, and many other processes.

The system is more distributed than the phrase “master clock” can imply. Molecular clocks also operate in tissues throughout the body, including the liver, pancreas, heart, lungs, gastrointestinal tract, adipose tissue, skeletal muscle, and other organs. These peripheral clocks help regulate functions that are particularly relevant to their tissues, such as glucose metabolism in the liver and pancreas or metabolic activity in muscle.

This is one of the most fascinating discoveries of modern chronobiology. The body is not simply controlled by one timer in the brain. It contains a network of oscillators that must remain sufficiently coordinated with one another and with the external environment. Light strongly influences the SCN, while feeding, hormones, activity, temperature, and sleep can influence peripheral timing.

What Dr. Al Nuaimi Adds to the Conversation

Dr. Al Nuaimi’s book takes the scientific intuition that physiology changes with time and places it within a more holistic model of bodily and emotional life. In descriptions of The Biological Clock, she presents the body as having an ongoing internal dialogue in which particular organs, bodily functions, and emotional themes become especially significant at different times.

A distinctive feature of this framework is its use of two-hour periods. This resembles the traditional Chinese medicine organ clock, in which different organ systems are assigned periods of relative prominence across a twenty-four-hour cycle. Dr. Al Nuaimi extends this model into questions about emotional experience, health, behavior, food, and personal reflection.

It is important to understand what kind of claim this represents. Traditional organ-clock models belong to a historical medical system with its own concepts of organs, energy, balance, and bodily function. They should not be treated as identical to the molecular clocks studied in contemporary circadian biology. The two traditions share an interest in temporal organization, but similarity in concept does not prove equivalence in mechanism.

Organs Really Do Keep Time, but Not as Exclusive Two-Hour Shifts

Modern research provides strong evidence that many organs contain peripheral circadian clocks. Liver cells, for example, show rhythmic gene expression involved in metabolism. Pancreatic clocks participate in regulation of insulin and glucagon. Muscle clocks interact with energy use and physical activity, while circadian processes in the gastrointestinal tract influence digestion, motility, barrier function, and metabolism.

These rhythms are real, but they do not operate like workers taking exclusive two-hour shifts. The heart does not become active for two hours and then hand control to another organ. Every major organ continues functioning throughout the day and night, while particular physiological processes within that organ may rise, fall, or change according to circadian phase.

This distinction allows readers to appreciate the central insight of the organ-clock metaphor without overstating the evidence. The body genuinely possesses temporal organization at multiple levels. What modern science does not currently establish is that each organ has one fixed two-hour period of maximal energetic activity that applies uniformly to every person.

Traditional Chinese Medicine and Chronobiology Ask Related but Different Questions

Traditional Chinese medicine has long emphasized rhythms in health, illness, and treatment. Its organ-clock framework divides the day into periods associated with different Zang-Fu systems and interprets these periods through concepts such as Qi, Yin and Yang, and relationships among organ systems. This is part of a broader theoretical structure that differs significantly from biomedical physiology.

Modern chronobiology asks questions using molecular, neurological, hormonal, behavioral, and physiological measurements. Researchers examine clock genes, melatonin, cortisol, body temperature, metabolic responses, neural pathways, sleep timing, and tissue-specific rhythms. These tools can demonstrate that biological functions vary over time without validating the traditional explanations for why they vary.

There are interesting parallels. Both frameworks recognize that time matters, that physiology is dynamic, and that health cannot always be understood as though the body behaves identically at every hour. Those parallels can encourage useful research. They do not mean that a traditional two-hour organ schedule has been scientifically proven by the discovery of peripheral circadian clocks.

Biological Timing Is More Than Sleep

One of the book’s valuable themes is that the biological clock extends beyond bedtime. This aligns with modern science. Circadian timing influences glucose regulation, appetite, hormonal secretion, cardiovascular physiology, immune activity, cognition, and physical performance in addition to sleep.

Meal timing provides a clear example. Metabolic responses vary with biological time, and repeatedly consuming large meals very late may produce different glucose and metabolic responses than eating the same food earlier. Physical activity can also influence circadian timing, particularly in peripheral tissues, while regular sleep and wake periods help maintain coordination between behavior and internal rhythms.

Still, none of this means there is one perfect hour for every activity. Chronotype, age, work schedules, health, latitude, cultural routines, and prior sleep all change how timing affects an individual. Circadian science supports attention to patterns more strongly than it supports rigid hourly prescriptions.

Light Remains the Strongest External Signal

Among the many influences on biological timing, light has the clearest and most powerful effect on the central circadian system. Light entering the eyes communicates environmental time to the SCN and can shift the phase of the circadian clock depending on when exposure occurs.

Daytime light, particularly outdoor light, helps establish a strong biological distinction between daytime and nighttime. Evening and nighttime light can also influence circadian timing, although the effect depends on brightness, duration, wavelength, prior exposure, and individual sensitivity.

This makes light one of the most practical areas where scientific circadian advice is relatively straightforward. People generally benefit from receiving meaningful light during the waking day and avoiding unnecessarily bright environments when preparing for sleep. The recommendation is broad because human environments and schedules vary.

Stress Can Affect Rhythms Without Creating One Universal “Emotional Clock”

Dr. Al Nuaimi’s framework emphasizes relationships among emotion, physiology, and time. Modern science does support important connections in this area. Stress can affect sleep timing, hormone secretion, appetite, activity, and daily routines, while circadian disruption and sleep loss can influence emotional regulation and mood.

However, this does not establish a precise timetable in which one specific emotion naturally belongs to one organ or one two-hour window. Emotional experiences are shaped by cognitive appraisal, relationships, current events, personality, sleep, health, environment, and many interacting neural systems.

Someone may notice that irritability tends to appear at a particular point in the day, but several explanations are possible. They may be hungry, sleep deprived, overloaded after work, dealing with repeated environmental stress, or experiencing a predictable decline in alertness. Personal timing patterns can be informative without being interpreted as evidence that one organ or emotional energy is active at that hour.

Observing Your Rhythm Can Still Be Useful

One of the most practical ideas in the book is to become more attentive to changes in energy, hunger, focus, sleepiness, and mood across the day. Self-observation can reveal patterns that are easy to miss when every day is treated as one continuous block of time.

A useful experiment is to track sleep and waking, major meals, caffeine, physical activity, focused work, and subjective energy for one or two weeks. A longer observation period is more informative than a few days because sleep debt, workload, weekends, illness, and chance events can distort short-term impressions.

The goal should be pattern recognition rather than diagnosis. If you repeatedly concentrate better later in the morning, that may help you schedule demanding tasks when possible. If large late meals consistently worsen sleep or reflux, timing may be worth adjusting. If mood drops every afternoon, however, that observation should lead to questions rather than an assumption that a particular organ is responsible.

Your Body Sends Signals, but Signals Need Interpretation

Holistic health language often encourages people to “listen to the body,” and there is value in taking fatigue, hunger, pain, tension, or sleepiness seriously. These experiences provide information about physiological and psychological state.

The challenge is that bodily signals are not self-interpreting. Fatigue can reflect insufficient sleep, infection, anemia, medication effects, depression, stress, low energy intake, sleep apnea, or many other causes. Abdominal discomfort can result from meal size, reflux, infection, food intolerance, gastrointestinal disease, stress, or ordinary variation.

Listening therefore should mean noticing and investigating, not assuming that every symptom contains a symbolic message. Awareness becomes more useful when combined with medical knowledge, context, and evidence.

Food Timing Matters Without One “Digestive Peak”

The idea that digestion has a rhythm is scientifically plausible and increasingly well supported. Gastrointestinal motility, hormone secretion, glucose responses, and metabolic activity vary across the day. Peripheral clocks in the liver, pancreas, gut, and other metabolic tissues respond to feeding schedules.

That does not mean the digestive system is active only during one particular traditional time window. Digestion continues whenever food is consumed, and humans can adapt to diverse cultural meal patterns.

A practical interpretation is to avoid extremes when possible. Habitually eating very large meals deep into the biological night may be less favorable for some metabolic outcomes, while more consistent meal timing can support routine. The exact schedule should still account for health, culture, work, medication, appetite, and individual circumstances.

Emotional Reflection Does Not Have a Proven Biological Hour

The book’s holistic approach encourages readers to consider when they feel most ready to reflect, plan, or process emotional experiences. This can be a worthwhile personal practice because cognitive performance and emotional availability do fluctuate with sleep, stress, and daily responsibilities.

What science does not establish is a specific circadian window during which difficult memories or particular emotions should be processed. Psychotherapy does not currently assign grief, fear, anger, or reconciliation to particular organ-clock hours.

If someone finds reflection easier at night, that preference can be honored. Another person may think more clearly during a quiet morning walk. The useful variable is whether the time supports attention and emotional capacity, not whether it matches a predetermined organ schedule.

Cultural Rhythms Matter Too

One of the more interesting dimensions of discussing biological timing in an Arabic cultural context is that daily time is already shaped by recurring social and religious patterns. Prayer, fasting, work, family meals, Ramadan schedules, and seasonal changes can substantially alter sleep, eating, and activity timing.

These cultural rhythms should not be reduced simply to biological interventions. Prayer times, for example, have religious meaning independent of their effects on sleep or circadian physiology. At the same time, researchers can legitimately study how recurring cultural practices interact with sleep, metabolism, mood, and daily behavior.

This broader perspective helps prevent circadian science from assuming that everyone follows a Western nine-to-five schedule. Biological timing is universal, but the social environments in which it operates are not.

What “Living in Sync” Should Really Mean

Living in sync does not require obeying every fluctuation in energy. Human beings are capable of working when tired, eating at unusual times, traveling across time zones, caring for children at night, and adapting to changing schedules. Flexibility is one of the strengths of human physiology.

A more realistic definition of circadian alignment is maintaining enough consistency and environmental contrast that the body receives reasonably coherent information about when activity and rest usually occur. Daylight exposure, adequate sleep, reasonably regular schedules, sustainable meal timing, and physical activity can all contribute.

The goal is not perfect harmony. Even healthy people experience late nights, disrupted sleep, unusual meals, emotional stress, and changing routines. Problems become more significant when misalignment is persistent, substantial, or associated with impaired sleep and functioning.

When Personal Observation Is Not Enough

Circadian awareness can help with ordinary lifestyle patterns, but persistent symptoms should not be interpreted solely through the biological clock. Severe daytime sleepiness, chronic insomnia, repeated inability to wake at required times, persistent fatigue, or major changes in mood may require professional assessment.

Circadian rhythm sleep-wake disorders are genuine clinical conditions, and treatment can involve carefully timed light exposure, melatonin, behavioral interventions, or schedule changes. Timing is particularly important because the same intervention can have different effects depending on biological phase.

Medical symptoms attributed to an “organ clock” should likewise be evaluated through ordinary clinical care when appropriate. A symptom occurring at a particular hour does not by itself identify the organ or mechanism responsible.

Reading The Biological Clock with Scientific Curiosity

Dr. Reem Al Nuaimi’s The Biological Clock is most useful when read as an integrative framework rather than a substitute for contemporary circadian medicine. Its central invitation, to recognize that the body is rhythmic and that daily timing may matter, is strongly compatible with modern chronobiology.

Its more specific claims about two-hour organ periods, emotional associations, internal energetic states, and traditional correspondences belong to a different conceptual system. Some may generate interesting hypotheses or provide readers with meaningful metaphors, but they should not be presented as established consequences of molecular circadian research.

Keeping these levels distinct does not diminish the book. It allows readers to appreciate its holistic and culturally informed perspective while still asking which claims have strong biomedical evidence, which are emerging possibilities, and which remain rooted primarily in traditional theory.

Final Reflection

The science of time has changed how researchers understand the human body. We now know that biological function is deeply rhythmic, that clocks exist in tissues throughout the body, and that light, food, activity, sleep, hormones, and behavior interact with this temporal organization. Health cannot always be understood without considering when physiological events occur.

Dr. Reem Al Nuaimi’s The Biological Clock approaches that truth through a wider lens, combining bodily timing with traditional organ-clock ideas, emotion, personal reflection, and holistic health. Its distinctive contribution is not that it provides a scientifically proven hourly map of every organ and emotion, but that it invites readers to think about time as an active dimension of human experience rather than merely a number on a clock.

Modern chronobiology and traditional organ-clock theory should therefore remain distinguishable. Peripheral clocks are scientifically established, while fixed two-hour organ-emotion correspondences remain part of a traditional framework that requires separate evidence. Recognizing the distinction makes it possible to engage with both thoughtfully rather than forcing them into artificial agreement.

Perhaps the most useful lesson is also the simplest: pay attention to rhythm. Notice how light, sleep, food, activity, work, stress, and culture organize your days. Use those observations to make reasonable adjustments, but resist the temptation to assign every symptom or emotional fluctuation to one hour or organ. Time matters profoundly in human biology, yet the human biological clock is a coordinated, flexible system rather than a rigid timetable.

References

Al Nuaimi, R. (2019). الساعة البيولوجية [The Biological Clock]. Biri Publishing.

Bautista, J. S., Ojeda-Mosquera, J. C., Ordóñez-Lozada, L. A., & López-Cortés, A. (2025). Peripheral clocks and systemic zeitgeber interactions: From molecular mechanisms to circadian precision medicine.

Knutson, K. L., Dixon, D. D., Grandner, M. A., et al. (2025). Role of circadian health in cardiometabolic health and disease risk: A scientific statement from the American Heart Association. Circulation, 152(21), e408–e419.

Samuels, N. (2000). Chronotherapy in traditional Chinese medicine. The American Journal of Chinese Medicine, 28(3–4), 419–423.

Wang, X., et al. (2016). Human biological rhythm in traditional Chinese medicine. Journal of Traditional Chinese Medical Sciences, 3(4), 206–211.