Disruption of the Circadian Clock Linked to Increased Bone Breakdown During Daytime

Inner Clock Influences Bone Breakdown, New Research Reveals

London, UK – September 26, 2025 – The intricate processes of bone renewal are inextricably linked to our internal body clock, according to a new study conducted by researchers at the University of Surrey and the University of sheffield. The findings, published in Scientific Reports, illuminate a previously underappreciated connection between circadian rhythms and bone metabolism.

The Rhythmic Renewal of Bone

Scientists have long understood that bones are dynamic tissues, constantly undergoing a process of remodeling that involves both bone formation and bone resorption – the breakdown and removal of old or damaged bone. This latest research highlights that bone resorption, specifically, is tightly regulated by our circadian rhythms, the natural, internal processes that control our sleep-wake cycle and other bodily functions.

The inquiry involved meticulously monitoring blood samples from 22 young adults over a 26-hour period, collecting data every two hours. Researchers measured levels of serum procollagen type I N-terminal propeptide (sPINP) – an indicator of bone formation – and C-terminal telopeptide of type 1 collagen (sCTX), a marker of bone resorption.

Circadian Control of Bone Resorption

The results indicated a striking difference in how these two processes are regulated. While bone formation appeared independent of the body’s daily cycle, bone resorption demonstrably fluctuated in sync with the circadian clock. This suggests that the timing of bone breakdown is not random, but rather, is subject to a precise internal timing system.

Dr. Andrea Darling, a nutritional Sciences Postdoctoral Researcher at the University of surrey and lead author of the study, explained, “This study definitively establishes a link between circadian rhythms and bone resorption, which is essential for maintaining bone integrity.” She added that future research will focus on whether older adults, especially those with osteoporosis, exhibit disrupted circadian rhythms that could contribute to bone loss.

Implications for shift Workers and Sleep Patterns

Professor debra Skene,FMedSci,of the University of Surrey’s Section of Chronobiology,emphasized the potential implications for individuals with disrupted circadian rhythms,such as shift workers. “Misalignment of these rhythms, commonly seen in those working non-traditional hours, could impact bone density and increase the risk of conditions like osteoporosis,” she stated.

According to the National Sleep Foundation, approximately 26% of the U.S. workforce works shifts other than the standard 9-to-5 schedule. the National Sleep Foundation reports that shift work can lead to chronic sleep deprivation and circadian disruption, potentially affecting numerous aspects of health.

Professor Richard Eastell, Professor of Bone Metabolism at the University of Sheffield, noted that the study’s rigorous methodology, utilizing a “constant routine” protocol, definitively confirmed the circadian nature of the observed bone resorption rhythm.

Did You Know? Approximately 10 million Americans have osteoporosis, and another 44 million have low bone density, increasing their risk of fractures.

Expert Perspectives on the Findings

Craig Jones, Chief Executive of the Royal Osteoporosis Society, hailed the research as a notable step forward. “This engaging study sheds new light on the fundamental biology of bone renewal. It raises critically important questions about whether disrupted sleep and shift work could heighten the risk of osteoporosis, and we are proud to have funded this crucial work,” he commented.

process	Circadian Rhythm Link
Bone Formation	No significant link
Bone Resorption	Strongly linked to circadian clock

Pro Tip: Prioritizing consistent sleep schedules and maximizing exposure to natural light can help maintain a healthy circadian rhythm, potentially supporting optimal bone health.

Understanding Circadian Rhythms

Circadian rhythms are fundamental to life, influencing a wide range of physiological processes beyond bone metabolism.These rhythms, which are roughly 24-hour cycles, are regulated by a master clock in the brain and are impacted by external cues like sunlight and social interactions. Maintaining a healthy circadian rhythm is vital for overall well-being,impacting mood,hormone regulation,and immune function.

Disruptions to circadian rhythms have been linked to an increased risk of several health problems, including obesity, diabetes, cardiovascular disease, and certain cancers. Therefore, prioritizing sleep hygiene and establishing regular routines are essential for supporting optimal health.

Frequently Asked Questions About Circadian Rhythms and Bone Health

• What are circadian rhythms?

  These are natural, internal processes that regulate the sleep-wake cycle and repeat roughly every 24 hours.

• How does bone resorption relate to osteoporosis?

  Excessive bone resorption can lead to a decrease in bone density, a hallmark of osteoporosis.

• Can shift work affect bone health?

  Yes,disruption of circadian rhythms due to shift work may increase the risk of bone loss.

• Is bone formation affected by circadian rhythms?

  This study found no significant link between bone formation and the body’s internal clock.

• What can I do to support healthy circadian rhythms?

  Maintain a consistent sleep schedule, maximize exposure to natural light, and establish regular routines.

• What is the role of Vitamin D in bone health?

  Vitamin D is essential for calcium absorption, which is crucial for building and maintaining strong bones.

• How often should adults have their bone density checked?

  Recommendations vary based on risk factors, but generally, women over 65 and men over 70 should have bone density screenings.

Does this research change how you think about the connection between sleep and overall health? Share your thoughts in the comments below!

What are the specific mechanisms linking circadian disruption to increased cortisol levels and subsequent bone resorption?

Understanding the Circadian Rhythm and Bone Health

The human body operates on a roughly 24-hour cycle known as the circadian rhythm. This internal clock regulates numerous physiological processes, including sleep-wake cycles, hormone release, body temperature, and, increasingly, bone metabolism. Emerging research strongly suggests a link between circadian disruption and increased bone resorption – the breakdown of bone tissue – particularly during daylight hours. This connection has meaningful implications for individuals working irregular shifts,experiencing jet lag,or suffering from sleep disorders.

The Core temperature Rhythm & Sleep-Wake Cycle’s Influence

Early models of the human circadian system, like the three-oscillator model proposed by Kawato, Fujita, and Suzuki in 1982 (J theor Biol 1982;98:369-92), highlighted the interplay between core temperature and the sleep-wake cycle. These foundational studies, alongside later work by Hastings (BMJ 1998;317:1704-7), laid the groundwork for understanding how disruptions to these core rhythms can cascade into broader physiological imbalances. specifically,alterations in these rhythms can affect the activity of osteoclasts,the cells responsible for bone resorption.

How Circadian Disruption Impacts Bone Metabolism

Several mechanisms explain the link between a misaligned circadian clock and increased bone breakdown:

* cortisol Levels: Cortisol, a stress hormone, naturally peaks in the morning to promote wakefulness. However, chronic circadian disruption can lead to elevated cortisol levels throughout the day, even during times when it should be low. High cortisol is known to stimulate osteoclast activity, accelerating bone loss.

* Vitamin D Synthesis: Sunlight exposure is crucial for vitamin D synthesis, which is essential for calcium absorption and bone health. Irregular sleep schedules and shift work often reduce daytime sunlight exposure, leading to vitamin D deficiency and impaired bone metabolism.

* Melatonin Imbalance: Melatonin, primarily produced during darkness, plays a role in regulating bone formation. Circadian disruption suppresses melatonin production, potentially hindering bone-building processes.

* Inflammation: Chronic circadian misalignment is associated with increased systemic inflammation. Inflammatory cytokines can directly stimulate osteoclast activity and contribute to bone loss.

Shift Work and Bone Density: A Real-world Example

Studies consistently demonstrate lower bone mineral density (BMD) in individuals working rotating shift schedules compared to those with regular daytime work hours. This is particularly pronounced in women. The constant disruption of the circadian rhythm, coupled with lifestyle factors common among shift workers (poor diet, reduced physical activity), creates a perfect storm for bone loss.

Identifying Individuals at risk

certain populations are more vulnerable to the negative effects of circadian disruption on bone health:

* Shift Workers: Nurses, doctors, emergency responders, and factory workers are at high risk.

* Frequent Travelers: Jet lag repeatedly throws off the circadian clock, increasing bone breakdown.

* Individuals with Sleep Disorders: Conditions like insomnia and sleep apnea disrupt sleep patterns and circadian rhythms.

* Older Adults: The circadian rhythm naturally weakens with age, making older adults more susceptible to disruption.

* Individuals with Mental Health Conditions: Depression and anxiety are often associated with sleep disturbances and circadian misalignment.

Diagnostic tools & biomarkers

Currently, there isn’t a single test specifically designed to assess the impact of circadian disruption on bone health. However, healthcare professionals can utilize several tools:

* Bone Mineral Density (BMD) Scan: A DEXA scan measures bone density and can identify osteoporosis or osteopenia.

* Blood Tests: Assessing levels of vitamin D, calcium, cortisol, and inflammatory markers can provide insights into bone metabolism.

* Actigraphy: A wrist-worn device that monitors sleep-wake patterns and can help identify circadian misalignment.

* Salivary Cortisol Testing: Measures cortisol levels throughout the day to assess the circadian cortisol rhythm.

Strategies to Mitigate the Effects of Circadian Disruption on Bone

While completely eliminating circadian disruption may not always be possible,several strategies can help minimize its impact on bone health:

* Prioritize Sleep: Aim for 7-9 hours of quality sleep per night,even on days off.

* Optimize Light Exposure: Maximize sunlight exposure during the day and minimize exposure to blue light from electronic devices in the evening.

* Maintain a Regular Meal Schedule: Eating meals at consistent times can help reinforce the circadian rhythm.

* Regular Exercise: Weight-bearing exercises stimulate bone formation.

* Vitamin D and Calcium Supplementation: Consult with a healthcare professional to determine appropriate dosage.

* Melatonin Supplementation: May help regulate sleep-wake cycles, but should be used under medical supervision.

* Chronotherapy: A therapeutic approach that aims to realign the circadian rhythm through timed exposure to light and other stimuli.

The Future of Circadian Rhythm and Bone Health research

Ongoing research is focused on:

* Identifying specific