Clinical Research Directory

Effect of Circadian Rhythm on the Sedative Efficacy and Recovery Quality of Ciprofol General Anesthesia: A Multi-Center Observational Study

The goal of this multi-center observational study is to learn about the effect of circadian rhythm (morning vs. afternoon surgery) on the sedative efficacy, hemodynamic stability (especially induction-associated hypotension), and recovery quality of ciprofol general anesthesia in adult patients undergoing elective non-cardiac and non-cranial surgery, comparing target-controlled infusion (TCI) and non-TCI administration modes. The main question it aims to answer is: Does circadian rhythm (time of surgery: morning vs. afternoon) affect the sedative efficacy, incidence of induction-associated hypotension, and recovery quality of ciprofol general anesthesia? Eligible patients aged 18-65 years with ASA physical status I-II and BMI 18-30 kg/m² undergoing elective general anesthesia for non-cardiac and non-cranial surgery (duration 1-2 hours) will be grouped by anesthesia start time (morning: 08:00-11:00; afternoon: 14:00-17:00) and receive ciprofol induction and maintenance via TCI or non-TCI infusion. Perioperative data including hemodynamic changes, ciprofol dosage, recovery time, and adverse events will be recorded and analyzed.

Digital Insomnia and Circadian Therapy for Reducing Depression Symptoms in College Students

Depression is a leading cause of global disease burden, poor quality of life, disability and suicide, and commonly occurs in adolescence and early adulthood. Insomnia and circadian factors were regarded as potential targets for preventing worsening of depressive symptoms. Additionally, digital insomnia treatment reduces depressive symptoms but is insufficient for individuals with an evening chronotype. Circadian intervention is an adjunctive treatment for sleep disturbance and depression, but is often overlooked. In this study, we aim to evaluate the effect of guided digital insomnia and circadian intervention (dCBT-I + dCI) in reducing depressive symptoms in college students with insomnia and an evening chronotype compared with digital insomnia intervention alone (dCBT-I) and a health education group (dHE). We also aim to develop and evaluate multimodal prediction models to identify individuals who are more or less likely to respond to the interventions, using clinical, behavioral, circadian, and digital engagement data.

Effects of Afternoon Napping, Caffeine, and Standardised Active Recovery on Evening Athletic Performance

This study evaluated whether afternoon napping, caffeine ingestion, and a standardised active recovery and nutritional protocol could influence evening physical and cognitive performance in healthy university athletes. Participants completed five experimental conditions in a randomised crossover design: placebo without napping, napping with placebo, caffeine without napping, napping combined with caffeine, and napping combined with caffeine plus a standardised active recovery and nutritional protocol. The nap opportunity lasted 90 minutes and caffeine was administered at 5 mg/kg body mass. The main outcome was repeated agility performance. Additional outcomes included sprint performance, jumping performance, reaction time, subjective sleepiness, sleep characteristics during the nap opportunity, and selected physiological measures. The study also explored whether responses differed according to sex and chronotype.

Light Timing Study

Chronic circadian misalignment and sleep restriction peak during late adolescence, and are associated with morning daytime sleepiness, poor academic performance, conduct problems, depressed mood, suicidal ideation, substance use, insulin resistance, and obesity. Bright light exposure from light boxes can shift rhythms earlier (phase advance) to facilitate earlier sleep onset and reduce morning circadian misalignment and the associated risks. To phase advance circadian rhythms, the investigators' PRCs showed that the ideal time to begin light exposure was slightly before wake-up time and light should be avoided around bedtime because this is when light produces maximum phase delay shifts. An unexpected finding from these results, however, was a second advancing region in the afternoon (\~6 to 9 h after habitual wake-up time) suggesting that afternoon light may have more circadian phase advancing ability than traditionally thought. The overall goal of this mechanistic study is to follow-up on the unexpected PRC findings and test whether individually-timed afternoon light alone and in combination with morning bright light can shift circadian rhythms earlier in older adolescents. Four groups will be compared in a randomized parallel group design: afternoon bright light, morning bright light, morning + afternoon bright light, and a dim room light control. Adolescents will complete a 2-week protocol. After a baseline week with a stable sleep schedule, adolescents will live in the laboratory for 7 days. Sleep/dark and the time of bright light exposure will gradually shift earlier. Bright light (\~5000 lux) will be timed individually based on his/her stable baseline sleep schedule. The first 3-h morning bright light exposure will begin 1 h before wake on the first morning. The first 3-h afternoon bright light exposure will begin 5 h after wake. The morning + afternoon exposures will begin at the same times, but each exposure will be 1.5 h so that a total of 3 h of bright light per day will be given to each group except the dim light control group. Phase shifts of the circadian clocks marked by the dim light melatonin onset (DLMO) is the main outcome. Investigators hypothesize that afternoon bright light will work synergistically with morning bright light to produce larger shifts than morning or afternoon bright light alone. These data could challenge the current understanding of how to use bright light to shift circadian rhythms earlier.

Pistacho and Sleep Quality

The goal of this study is to evaluate the effect of pistachio (Pistacia vera L.) consumption on plasma melatonin, antioxidant capacity, and circadian rhythms in overweight young adults. The main question it aims to answer are: * Can the consumption of pistachios, specifically their content of compounds like phyto-melatonin, effectively regulate the human biological clock and circadian rhythms?

SCREENS: Sleep, Circadian Rhythms, and Electronics in the EveNing Study

The proposed project aims to disentangle the impact of evening light exposure emitted from tablet devices from the impact of arousing media content on children's sleep regulation, circadian physiology and next-day emotion regulation and executive functioning.

Hyperthermia in Patients With Chronic Primary Pain - Effects on Thermoregulation, Somatosensory System and Movement Evoked Pain

This study, in a quasi-experimental matched two-group pre-post design, investigates the effect of serial water-filtered whole-body hyperthermia on circadian core body temperature, the somatosensory system (nociception) and the movement evoked pain in healthy and patients with chronic primary pain (e.g., fibromyalgia). The intervention lasts 3 weeks with two treatment sessions per week.

Circadian Rhythm Monitoring Study

This will be a single-center, prospective observational study designed to evaluate the feasibility and accuracy of a new wearable device for non-invasive continuous monitoring of physiological signals to derive circadian rhythm. Melatonin sampling will be included for comparison against wearable-derived measures

Sleep Loss and Circadian Misalignment - Mechanisms of Insulin Resistance

The purpose of this study is to examine the impact of timed cortisol release or differently timed cortisol rhythms on insulin resistance in both men and women undergoing sleep restriction. Chronic sleep loss is highly prevalent, affecting 1 in 3 adults in the US. Chronic sleep loss causes stress which induces insulin resistance and leads to obesity and type 2 diabetes. Many factors contribute to sleep loss including shift work, environmental disturbances, sleep/circadian disorders and comorbid medical and mental health conditions. Sleep loss increases the stress hormone cortisol in the evening and decreases daytime testosterone. Examining these hormones in a controlled laboratory environment under different sleep schedules may help researchers find solutions for adults experiencing negative health consequences related to chronic sleep loss.

Time to Move in Pregnancy Hyperglycemia

This randomized controlled crossover trial of 36 pregnant individuals with gestational diabetes (GDM) or gestational glucose intolerance (GGI) will: 1. Determine the effects of physical activity (PA) timing, specifically 30 minutes of moderate intensity walking or stepping in the morning (between 5am-9am, within 30-40 minutes of starting breakfast), versus late afternoon/evening (between 4pm-8pm, within 30-40 minutes of dinner) on glucose across the 24-hour cycle. 2. Explore the potential effects of the timing of PA on sleep and mood state.

Early Pregnancy Lifestyle and Glucose Patterns: A Substudy of TOFFFY

The goal of this clinical trial is to examine how daily behavioral patterns in early pregnancy, including sleep, physical activity, and meal timing, influence continuous glucose dynamics and subsequent risk of gestational diabetes mellitus (GDM) in pregnant women without pre-existing diabetes. The main questions it aims to answer are: 1. Do early-pregnancy chronobehavioral patterns (e.g., irregular sleep, night eating, and unstable rest-activity rhythms) relate to continuous glucose patterns measured using continuous glucose monitoring (CGM)? 2. Can early behavioral and CGM-derived measures predict glucose regulation and metabolic outcomes later in pregnancy (24-28 weeks)? 3. Does real-time self-monitoring using wearable devices and food logging improve glycemic outcomes compared to usual care? This study is a prospective, nested randomized pilot trial embedded within the ongoing Towards Optimal Fertility, Fathering and Fatherhood studY (TOFFFY) cohort (NCT06293235) at KK Women's and Children's Hospital, Singapore. A total of 140 pregnant women without pre-existing diabetes, recruited at ≤13 weeks gestation, will be randomized in a 1:1 ratio to either a pilot arm (wearable-based self-monitoring) or a control arm (usual care). Participants in the pilot arm (n=70) will undergo intensive behavioral and metabolic monitoring over a 14-day period in early pregnancy, including continuous glucose monitoring using a CGM device, wrist actigraphy to assess sleep-wake and rest-activity patterns, and an AI-supported mobile application to record meal timing and dietary intake. Participants will have real-time access to their glucose data and behavioral feedback, enabling self-monitoring and potential behavioral adjustments.

THE EFFECTS OF CIRCADIAN RHYTHM-BASED PROGRESSIVE RELAXATION EXERCISES IN HEMODIALYSIS PATIENTS

The aim of this study is to determine the effect of Progressive Relaxation Exercise (PGE) applied according to the circadian rhythms of hemodialysis (HD) patients on symptom management, sleep quality, comfort and mental well-being levels and to examine the experiences of HD patients regarding PGE application. A sequential mixed method research design will be used in the study. The quantitative part of the study was planned as a randomized controlled double-blind experimental study. The qualitative part will be conducted as a qualitative research to be carried out with individual in-depth interview method in order to examine the opinions of the individuals in the intervention group regarding the 8-week PGE applied according to the circadian rhythm. In the collection of research data, the Introductory Information Form, Morningness-Eveningness Questionnaire (MEQ), Dialysis Symptom Index, Hemodialysis Comfort Scale - Version II, Pittsburg Sleep Quality Index (PSQI), Warwick-Edinburgh Mental Well-Being Scale (WEMIOÖ), Individual Follow-up Form, Progressive Relaxation Exercise Application Guideline (PGEUY) and In-Depth Interview Form with Individuals in the Intervention Group will be used.

Cannabis Effects on Sleep, Circadian Rhythms, and Light Sensitivity in Young Adults

The goal of this study is to learn how cannabis use and discontinuation affect sleep, circadian rhythms, and sensitivity to light. The main questions it aims to answer are: 1. Does cannabis use and discontinuation impact sleep drive? 2. Does cannabis use and discontinuation impact light sensitivity and circadian phase?

Sleep Survey for Medical Trainees

Background This is a survey to understand sleep in the context of medical trainees (on call) and the participants knowledge about the relevance of sleep, shiftwork, and the impact that sleep may have on their working performance. The survey has been developed by sleep experts from America, Europe, and Africa, in collaboration with the World Sleep Society. It should take about 30-40 minutes to complete. The survey will focus on three different aspects, complemented by two standard questionnaires: 1. Demographics and Place of Work 2. Basic Knowledge and Perception of Sleep 3. Sleep Routine 4. Epworth Sleepiness Scale, Insomnia Sleep Inventory

Effect of Esketamine on Postoperative Sleep in Postmenopausal Women

The prevalence of sleep disturbance among postmenopausal women has been reported to reach 51.6%. Epidemiological studies consistently show that the incidence of sleep disorders increases with age and menopausal transition. Compared with premenopausal women, postmenopausal women demonstrate reduced circadian rhythm stability and a higher prevalence of sleep disturbance. In this population, levels of melatonin, total sleep time, sleep latency, N3 stage sleep, and the circadian amplitude of alertness are all diminished. Sleep disturbance can adversely affect both the mental and physical health of women and significantly impair their social functioning. Poor sleep is associated with decreased cognitive performance and heightened emotional distress, contributing to diminished quality of life. Circadian rhythms are endogenous physiological and behavioral cycles that oscillate over approximately 24 hours, governing critical processes such as sleep-wake cycles, hormonal fluctuations (e.g., cortisol and melatonin). These rhythms are regulated by the suprachiasmatic nucleus (SCN). Disruptions in circadian rhythms have been associated with sleep disturbances. Esketamine is the S (+) enantiomer of ketamine and has a higher affinity for the NMDA receptor than the R-enantiomer. Previous studies have demonstrated that intraoperative administration of esketamine can improve postoperative sleep quality and reduce the incidence of postoperative sleep disturbances, through its antidepressant efficacy, anti-inflammatory properties, analgesic efficacy, neurocognitive and anxiolytic effects. However, few studies have investigated whether esketamine can regulate perioperative circadian rhythms and subsequently affect sleep, especially in postmenopausal women. The objective of this multi-center, prospective, randomized controlled clinical trial is to investigate the effects of esketamine on postoperative sleep in postmenopausal women.

Feasibility of Wearables in Dementia Care in Rural Taiwan

Taiwan is becoming a super-aged society, and more older adults are living with Alzheimer's disease. Many people with Alzheimer's experience behavioral and psychological symptoms, such as agitation, sleep problems, or mood changes. These symptoms often lower their quality of life and increase stress for their family caregivers. This study will test two wearable devices in people with Alzheimer's and their caregivers. One device, called Geneactiv, is a wristwatch that tracks daily activity and sleep. The other device, called Re-Timer, is a light therapy eyewear that may help improve sleep and mood. Researchers will look at how easy the devices are to use, whether participants are willing to wear them for several weeks, and whether the light therapy helps reduce sleep problems or caregiver stress. The study will also compare information from questionnaires with information collected by the devices. The results may help researchers design future studies using wearable tools to better support people living with dementia and their caregivers.

Investigating the Effects of Time-of-day and Menstrual Cycle Phase (Low and High Progesterone) on Female's Cognitive and Strength Performance

This study is designed to determine whether time-of-day and menstrual cycle phase influence athletic performance and is expected to contribute valuable insight into how both time-of-day, and hormonal factors can influence performance and expand existing research. This study aims to support more inclusive, effective and personalised approaches to training and competition schedules for female athletes. The study will involve two testing days that require a participant to complete a compilation of tests at 07:00, 12:00 and 18:00 hours. The testing days will be arranged for when a participant is in phase 1 (lowest levels of progesterone in the menstrual cycle) and phase 4 (highest level of progesterone in the menstrual cycle). The tests will examine a participant's executive function and physical strength. This study will aim to recruit thirty 18-30-year-old females from Lancaster University who identify with a sport that they train \~3 times a week for with a purpose to compete. The females recruited must have a regular menstrual cycle and no history of sleep disorders. Aim: To investigate the effects of time-of-day and menstrual cycle phase (low and high progesterone levels) on executive function and strength in females. Objectives: 1. To determine the effects of time-of-day on executive function and strength tests. 2. To determine the effects of menstrual cycle phase on executive function and strength tests. 3. To examine if there is an interaction between time-of-day and menstrual cycle phase on executive function and strength tests.

A Longitudinal Follow-Up Study on Predicting Major Depressive Disorder From Rest-Activity Rhythm Profiles

This proposed study will be a longitudinal follow-up study of a case-control study of 160 participants (CREC Ref: 2023.234). This study aims to follow up on the trajectory of depression and rest-activity rhythm (RAR) disruptions, as well as examine their association over time. The investigators aim to identify distinctive RAR profiles of MDD using the data from the original project and hypothesize that two or more groups will be identified based on individual RAR variables using cluster analysis. The investigators hypothesize that significant differences in depressive symptom severity, sleep quality, and other outcome measures collected in this follow-up will be found between the clustered groups. Individuals exhibiting the most disrupted RAR profiles are hypothesized to have the greatest deterioration in depression symptom severity and other outcome measures. The investigators also hypothesize that people persisting with MDD will exhibit greater disruptions in RAR compared to those without MDD at the follow-up. Furthermore, the investigators will examine whether individual RAR parameters are longitudinally associated with changes in depression symptom severity and other outcome measures.

Dietary Impact on Sleep, Rhythms and Related Physiology

Sleep and metabolism are closely interconnected, and emerging evidence suggests that dietary composition may influence both sleep quality and key physiological functions such as glucose regulation, cardiovascular activity, and hormonal signaling. This study aims to investigate how a Western-style unhealthy diet versus a healthier, fiber-rich diet affects objective and subjective sleep measures, 24-hour physiological parameters, and a range of biomarkers related to cardiometabolic, neurodegenerative, and gut microbial function.

Sleep and Circadian Contributions to Nighttime Blood Pressure

Broadly, this study (SCN-BP) seeks to examine sleep and circadian factors that contribute to blood pressure levels at night.

Nighttime Synchrony of Your Nutrition and Circadian Health

Sleep is an important factor for overall health. This study will see how different light exposure patterns and food intake impact a person's metabolism (how the body breaks down food) when sleeping is reduced. Participants will attend 6 to 8 in-person visits to the study clinic, including three overnight stays. People will complete surveys and medical tests. The study will last about 4 to 6 months.

This Trial Examines How Last Meal Composition and Timing Affect Sleep Quality and Circadian Gene Expression Among Medical Residents. Recruitment Not Yet Started; Study Begins Dec 2025 and Ends Dec 2026.

This randomized controlled trial aims to evaluate the effects of last meal composition and timing on sleep quality and circadian gene expression among medical residents in Jordanian hospitals. Sleep disturbances are common in this population due to long working hours, high stress, and irregular eating schedules. Chrono-nutrition, the science of aligning food intake with circadian rhythms, may provide a practical approach to improving sleep and overall well-being. Participants will be randomly assigned to one of three groups: 1. High-carbohydrate last meal (≈80% of dinner calories from carbohydrates), 2. High-protein last meal (≈40-50% of dinner calories from protein), 3. Control group consuming a balanced standard meal. Each participant will consume the assigned meal 3-4 hours before bedtime for two weeks. Sleep quality will be measured using the Pittsburgh Sleep Quality Index (PSQI) and smartwatch-derived parameters, while salivary samples collected pre- and post-intervention will be analyzed for CLOCK and BMAL1 gene expression. The study will also include dietary, anthropometric, and physical activity assessments. This study has been approved by the Institutional Review Board of the University of Jordan (IRB No. 491/2025). Recruitment has not yet started. Enrollment is expected to begin in December 2025, with primary data collection completed by June 2026 and final study completion by December 2026.

Light in Frail Elderly - the Effect of a Dynamic Light for Sleep and Circadian Rhythm

The aim of this project is to evaluate the effect of a dynamic light in order to improve the circadian rhythm, provide a better sleep and well-being, and in the long run an improved recovery. The primary question is whether dynamic artificial light with circadian stimulus can affect the circadian rhythm. The secondary question is whether this also provides better sleep and well-being. The group that is particularly interesting to study is a geriatric population that is more sensitive to circadian rhythm disorders, sleep disorders and confusion in connection with hospitalization and that can be of particular benefit from this intervention.

Chrono-ALIGN: A Chronotype-Based Chrono-Nutrition Intervention in Post-Bariatric Patients

This randomized controlled trial will evaluate the impact of chrono-nutrition, a dietary approach that aligns meal timing with the body's circadian rhythms, on weight change, metabolic outcomes, appetite, and gut microbiota in post-bariatric surgery patients. A total of 246 adults who underwent sleeve gastrectomy at least six months earlier will be enrolled at King Saud Medical City. Participants will be randomized to receive either standard post-bariatric nutritional care or personalized chrono-nutrition based on individual chronotype. Outcomes include weight change, metabolic biomarkers, dietary behaviors, sleep patterns, and gut microbiota composition. The study aims to determine whether integrating chrono-nutrition into post-bariatric follow-up can enhance metabolic health and improve long-term health.