What Is Body Clock? 12 Ways It Affects Our Health

The body cloc k is an internal timing system that regulates an organism’s circadian rhythms—natural cycles that control various physical, mental, and behavioral processes. It acts as the body’s built-in scheduler, coordinating activities and functions throughout the day.

What Is Body Clock?

The internal body clock is a natural timing mechanism that governs critical biological functions and behavioral patterns across all living organisms.

The body clock is also known as the circadian rhythm ¹; it involves the 24-hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to changes ² in light and the environments around us.

A common example of a light-related circadian rhythm is the natural tendency to sleep at night and stay awake during the day. This internal body clock also regulates vital functions such as metabolism, blood pressure, the sleep-wake cycle, and hormone production.

How Does The Body Clock Work?

This body clock is also characterized by homeostasis ³. Homeostasis is the process by which every living organism actively maintains stable conditions for survival. It is related to the pineal gland, the prime center of the body’s internal clock that regulates circadian rhythms.

The pineal gland receives information about the daily light-dark cycle from the retina and adjusts melatonin secretion accordingly. More melatonin is released in darkness, highlighting its crucial role in promoting sleep. In fact, melatonin serves as a key hormone linking the circadian system to the regulation of circadian rhythms.

However, melatonin is not the only factor involved. Other hormones—such as vasopressin, acetylcholine, insulin, and leptin—as well as body temperature, also influence the functioning of the body clock.

Our internal body clock plays a vital role in regulating various physiological processes, including metabolism, hormone release, and behavior. It enables all living organisms to align their biological functions with the Earth’s 24-hour rotation, allowing them to anticipate and adapt to environmental changes.

In mammals, influenced by the light/dark cycle, the circadian clock optimizes metabolism and energy harvesting. The sleep-wake cycle ⁴ is one of the most important circadian rhythms, synchronized as it is by a master clock in the brain.

Master clock

Some environmental cues, especially daylight ⁵, directly influence the master clock. It is a clock in the brain that coordinates all the other biological clocks in a living being’s body.

In vertebrate animals ⁶, including humans, it is a group of about 20,000 neurons ⁷ that form a structure called the suprachiasmatic nucleus (SCN). Situated in the hypothalamus of the brain, it receives direct input from the eyes. That’s why the day and light cycle is tied to the circadian rhythm.

What Affects The Circadian Rhythm?

The biological clock is shaped by behavioral patterns and external cues, such as light, temperature, and social activity. In turn, it governs several essential bodily functions, including:

1. Metabolism

The internal body clock and food intake are directly related to metabolism ⁸, as it is the only factor responsible for energy production.

2. Sleep

The body clock controls the sleep-wake cycle, with light being the main external stimulus that influences the rhythm.

3. Age

Aging ⁹ is also associated with the body clock. In fact, due to old age, elderly people experience difficulties in completing basic day-to-day activities linked to energy production and sleep.

4. Food

For synchronizing circadian rhythms, food is considered the main stimulus. This clock regulates cellular differentiations and the cell cycle. However, the process is yet to be understood well.

5. Immune response

It has been observed in research that body clock affects the immune system responsible for the change in response to bacterial infection. In particular, specialized cells called macrophages, which are big cells that engulf and kill bacteria.

6. Physical and psychological disorientation

Sometimes traveling may cause physical and mental exhaustion. Such a condition disrupts the body clock.

Causes Of Circadian Rhythm Disruptions

Circadian rhythm disruptions—and in more severe cases, body clock disorders—can arise due to various factors, including:

1. Shift work

Lifestyle patterns, especially shift work ¹⁰, can trigger circadian rhythm disorders. Several studies attest that constant or recurrent patterns of sleep interruption results in insomnia or excessive sleepiness.

Most night shift workers experience difficult sleeping patterns and disturbances in their bodily functioning. This can also trigger metabolic changes and severe changes in weight and mood.

2. Jet lag

When people travel across multiple time zones, they frequently face difficulties in adjusting to new schedules due to jet lag. Attributed to a brief disruption in the internal body clock, jet lag makes people experience brain fog, sleeping problems, and disoriented feelings.

3. Delayed sleep disorder

Delayed sleep disorder syndrome ¹¹ is a type of circadian rhythm disorder commonly prevalent in people who have a habit of staying awake into the late hours of the night and waking later in the morning. Mostly the younger generations, who are comfortable addressing themselves as ‘night owls”, experience its symptoms.

Read More About Sleep Disorders Here

4. Effect of drug and alcohol intake

Certain drugs and alcoholic drinks ¹² cause circadian rhythm disruptions, even inducing sleep disorders. Consuming alcohol during the evenings may cause unnecessary sleepiness, whereas consuming it late at night may cause sleep disruptions throughout the night. Other substance intakes (like narcotics) can also disrupt our body clock and mental health.

Read More About Alcoholism And Mental Health Here

5. Irregular sleep-wake disorder

People who are in the habit of taking short naps throughout the day or those with no proper sleeping pattern may experience body clock disorders, particularly irregular sleep-wake disorder.

Moreover, people with neurological conditions (such as dementia), children with intellectual disabilities, and people with traumatic brain injuries may also experience disruptions in the body clock.

Circadian Rhythm Disruption And Physical Health

Circadian rhythm disruptions can trigger certain physical health symptoms linked to:

Reduced life expectancy
Increased risk of cancer
Cardiovascular diseases (like stroke and heart attack)
Obesity
Metabolic syndromes

Read More About Obesity Here

Circadian Rhythm Disruption And Mental Health

Circadian rhythm disruption affects mental health—triggering severe mental health conditions like:

Irritability
Decision-making problems
Depressive disorders [Read more]
Mood disorders [Read more]
Sleep disturbances
Decreased alertness
Cognitive impairment (memory disorders like dementia, Parkinson’s disease, etc.).

Read More About Dementia Here

How To Maintain A Healthy Body Clock

The focus of the treatment of body clock disorders is to reset a disrupted circadian system and reinstate a healthy sleep-wake cycle. Specialists generally chalk out treatment plans depending on the severity of the problems experienced and the type of body clock disorder.

1. Bright light therapy

In this type of therapy, the patient is advised to plan a particular time daily to sit in front of a lightbox. The lightbox will provide a variety of bright lights, such as sunlight. Light visors and light glasses are generally used in this therapy. Bright light therapy ¹³ adjusts the amount of melatonin the body makes and resets the sleep cycle.

2. Melatonin supplement

Melatonin supplements ¹⁴ are generally prescribed to treat delayed sleep disorders, irregular sleep cycles, etc.

3. Healthy lifestyle changes

A healthy lifestyle ¹⁵ helps in reducing circadian rhythm disorder symptoms and, therefore, experts suggest patients follow a well-planned daily routine. This routine may include a scheduled meal time, a good sleep hygiene regime, adequate exercise, limited intake of caffeine and alcohol, etc.

Takeaway

A healthy body clock is essential for both mental and physical well-being, as well as for maintaining smooth daily functioning. That’s why it’s important to listen to your body’s natural rhythms and take steps to preserve them. However, in today’s fast-paced world, hectic schedules and irregular lifestyles can make it difficult to maintain habits that support a balanced circadian rhythm.

Resetting a disrupted body clock takes time, consistency, and conscious effort—and so does regaining your daily rhythm. But with lifestyle adjustments, you can expect noticeable improvements in motivation, energy levels, and overall productivity.

At A Glance

The body clock, or circadian rhythm, is an internal system that regulates the timing of essential physiological and behavioral functions in living organisms.
It governs key bodily processes such as metabolism, blood pressure, the sleep-wake cycle, and hormone secretion.
The body clock responds to environmental cues—especially light and darkness—to keep these processes synchronized with the 24-hour day.
When the body clock is disrupted, it can lead to various mental and physical health problems, including fatigue, mood disorders, and metabolic issues.
Fortunately, these disruptions are manageable through methods like light therapy, medications, and lifestyle adjustments that help reset and support natural circadian rhythms.

Frequently Asked Questions (FAQs)

1. How do mental disorders affect the circadian rhythm?

Mental health disorders like mood disorders, sleep disorders, eating disorders, and substance use disorders can disrupt the circadian rhythm, thereby enhancing the risk of body clock disorders.

2. How can we reset the body clock?

Attempting to follow a healthy lifestyle that includes regular meal and sleep times as well as adequate exercise can be a good step towards resetting and correcting a disrupted body clock.

3. What is the body clock and why is it important?

The body clock, or circadian rhythm, is your internal timer that regulates sleep, energy, and key bodily functions. Keeping it balanced supports better health, mood, and daily performance.