Previously, relegated to a nuance, sleep health plays a vital role in managing chronic diseases. A 2025 American Heart Association scientific statement particularly highlights circadian health as a modifiable driver of cardiometabolic risk, linking misalignment of body clocks with obesity, type 2 diabetes mellitus, hypertension, and increased risk of cardiovascular disease.
Understanding Process S and Process C: How Your Body Regulates Sleep
The way we fall asleep, stay asleep, and wake up is shaped by two interacting biological systems known as Process S (Sleep) and Process C (Circadian). Together, they form the “two‑process model” of sleep regulation. Process S, or the intrinsic sleep drive, reflects the body’s growing need for sleep the longer we stay awake. Sleep pressure builds throughout the day. As the brain cells use energy, there is a buildup and accumulation of chemical, adenosine. This substance inhibits wake‑promoting neurons, creating the sensation of sleepiness. After a night’s rest completing the sleep process, the adenosine levels drop, relieving this pressure and enhancing alertness for the next waking period. Process C, the circadian rhythm, is our internal 24‑hour clock. Governed by the “suprachiasmatic nucleus” a region of the brain that synchronizes with light and darkness to determine when we naturally feel alert or sleepy. This process is independent of how long we’ve been awake. Morning light strengthens alertness signals, while evening darkness triggers melatonin (an intrinsic sleep promotor) release. This naturally signals your body to sleep. Together, these processes create the daily ebb and flow of energy: we become sleepiest when high homeostatic sleep pressure aligns with the circadian clock’s sleep‑promoting phase.
Why Circadian health matters
The Circadian body clock (Process C) goes beyond just sleepiness. This process governs other processes in our body such as blood pressure, hormone release, metabolism, and vascular function through entrainment primarily by light. Disruption in this timing that is often seen in shift work, irregular meals, or evening bright light leads to insufficient and ineffective sleep resulting in a downstream physiological consequence. Sleep irregularity that leads to sleep debt and fragmented sleep has emerged as an important modifiable cardiovascular risk factor. Data from MESA (Multi-Ethnic Study of Atherosclerosis) indicated that greater day-to-day variability in sleep duration and timing was related to a 2 times higher Cardiovascular risk.
Why does this matter for healthcare business?
For healthcare executives, the impact of circadian disruption can be profound both for the executive and their workforce. This is most evident in shift-workers who experience 50% higher incidence of insomnia and 20% increased risk of cardiovascular disease, and 25% more workplace errors compared to day-shift workers. These impairments translate directly to higher organizational risk, increased coverage cost, and compromised patient safety. Cardiometabolic diseases remain among the most expensive conditions to manage for both work forces and patients. Circadian rhythm is emerging as a key player in cardiovascular and metabolic health. A robust circadian rhythm can optimize health and decrease cardiovascular risk, including cardiac events, hypertension control and others. It is a modifiable contributor to obesity and diabetes. Investing in circadian supportive strategies can improve workforce efficiency and reduce healthcare dollars.
Key Levers that healthcare leaders can utilize to impact circadian misalignment:
Light therapies
The internal clock can be influenced by external cues (Zeitgebers) that synchronize internal circadian rhythm to our environment. Light is the primary zeitgeber, making timed light exposure an effective tool for regulating the circadian rhythm. Exposure to light has been shown to improve mood, energy levels, and sleep quality. Current recommendations have shifted from using very bright light therapy (10,000 lux) to favoring short‑wavelength light (Blue-green light) at lower intensities. Conversely, bright evening light can cause irregular sleep. Research suggests that even light levels as low as 100 lux can suppress melatonin and delay the circadian influence on sleep. Several studies examining light‑based interventions on cardiometabolic outcomes have found that morning light exposure is associated with lower body fat, reduced body mass, and decreased appetite. For workers, Light-based interventions such as timed bright light therapy early in the shift and dim-light therapy can reduce errors and improve alertness and overall-wellbeing
Wearable technologies and direct to consumer feedback(Consumer sleep technologies)
Wearables offer continuous, non-invasive monitoring of sleep timing and duration that offer insight into circadian health. A common technology imbedded within wearable such as accelerometers help us identify when we are active versus rest. There is a strong association between irregular sleep timing (hallmarked by activity during sleep time) and cardiometabolic risk. A study looking at the impact of sleep timing on Type 2 diabetes showed Moderate and high sleep irregularity were associated with diabetes risk, even in participants who slept more that 7 hours per night. Sleep/rest tracking can be utilized as a tool to improve circadian performance and thus reduce cardiovascular risk. From a workforce health perspective, wearable programs can lower downstream clinical costs by addressing sleep disturbances with direct end user feedback before they progress into more disruptive sleep and inherent increase in medical costs.
Light optimized environments
Healthcare facilities often expose staff and patients to lighting that is not aligned to human physiology. Studies show that circadian adaptation to night shift workers were associated with higher REM (deep sleep) sleep durations. Thus, biologically aware lighting systems can improve sleep and alertness. These environmental investments can improve workforce satisfaction and patient safety scores.
Conclusion
Circadian health is a modifiable risk factor that can have a large impact on overall health. Utilizing light therapies, incorporating wearable technologies, and optimizing lighting in the workplace can indirectly reduce cardiovascular risk in the work force. Health care leaders that understand the importance of investing in circadian health can strategically strengthen workforce performance, enhance patient safety, and reduce operational costs.