Saliva & Circadian Rhythm in Medical Profiling for Early Disease Prevention

Circadian rhythms affect almost every biological process from hormone secretion, gene expression, immune regulation, and metabolism. Studies show that disruption to these internal rhythms through irregular sleep, artificial sleep, and irregular sleep can significantly increase risk for chronic disease such as diabetes, cardiovascular disorders, neurodegeneration, and cancer. Saliva presents a viable alternative for capturing biomarkers found through blood or cerebrospinal fluid, offering substantial utility for diagnostic and chronobiological profiling. Saliva contains hormones such as cortisol and melatonin while containing inflammatory markers that fluctuate rhythmically throughout the day. Due to its ease of collection, saliva is well suited for longitudinal monitoring, screening in most populations, and can be integrated into health platforms. Findings suggest salivary biomarkers can offer insight into when a dysfunction occurs. This time sensitivity allows clinicians to detect early biological changes before symptoms manifest. Saliva sampling removes logistical and ethical concerns associated with more invasive methods, making it ideal for repeated use in most community settings. Aligning diagnostic practices with circadian principles advances preventative care and creates a personalized model of medicine. This literature review examines the potential of salivary diagnostics with circadian biology to create time sensitive, patient friendly tools for disease prevention.