View clinical trials related to Circadian Rhythm.
Filter by:This project aims to test the impact of melatonin and MTNR1B variation on regulation glucose regulation in a highly controlled in-laboratory setting and ex vivo in pancreatic islets.
The circadian rhythm of copeptin will be examined in healthy subjects.
Low-dose aspirin is a cornerstone in the secondary prevention of cardiovascular disease (CVD) and is usually taken on awakening, although evidence regarding optimal time of intake is lacking. Platelet reactivity follows a circadian rhythm, with a peak in the morning, contributing to the morning peak of cardiovascular disease. Due to its short half life, aspirin only inhibits platelets which are present at the time of intake. Thus, the timing of aspirin intake may influence its inhibitory effect on platelets and intake of aspirin at bedtime may attenuate the morning peak of platelet reactivity. The time-dependent effect of aspirin on circadian rhythm of platelet function has never been studied before. We hypothesize that aspirin intake at bedtime compared with intake on awakening results in a reduction of the morning peak in platelet reactivity.
The study examines and illustrates the utility of utilizing actigraphic measurements to assess treatment response.
After focusing many years only on intraocular pressure (IOP) as the primary risk factor, recently the impact of ocular blood flow is getting more consideration for the pathophysiology of glaucoma. The circadian change of intraocular pressure (IOP) is well investigated, but diurnal variations in ocular blood flow are yet to be evaluated, especially in glaucomatous eyes. This study is performed to investigate circadian variation of ocular blood flow assessed by laser interferometric fundus pulsation amplitude (FPA) and laser Doppler flowmetry (LDF) in glaucomatous eyes during topical antiglaucoma therapy at 8:00, 12:00, 17:00 and 21:00, to compare these circadian variation of ocular blood flow in glaucomatous eyes with variations in healthy eyes and to relate blood flow variations with IOP variations.
Sleep is necessary for healthy functioning, and people who sleep too little or too much may have an increased risk of developing health problems. This study will examine people who regularly sleep for short or long amounts of time to understand the biological factors that determine how much sleep a person needs.
The purpose of this study is to investigate whether sleep disruption affects menstrual cycle timing
This study will determine which color of light is most effective in stimulating a range of biological functions in humans including activation of sleep-wake regulatory system (alertness, performance, microsleeps, brain activity), activation of the nervous system (heart rate, temperature, blood pressure, breathing rate), and shifting the timing of the internal 24-hour (circadian) pacemaker.
For many years researchers have been trying to better understand the regulation of sleep and activity by studying circadian (daily) rhythms of human beings. It appears that the hormones estrogen, progesterone, and testosterone play a role in the regulation of circadian rhythm in animals. Researchers believe these hormones may also play a similar role in the regulation of human circadian rhythms. Little research has been conducted on how these hormones affect human circadian rhythms. This study is designed to learn more about how specific hormones influence men and women's daily rhythms. This study will use women from another research study being conducted at the NIMH called, "The central nervous system effects of pharmacologically induced hypogonadotropic hypogonadism with and without estrogen and progesterone". Male subjects will be recruited from another NIMH study called, "The central nervous system effects of pharmacologically induced hypogonadotropic hypogonadism with and without testosterone replacement". In order to test the possibility that gonadal steroids (estrogen, progesterone, and testosterone) change circadian rhythms and the sleep-wake cycle in humans, participants will undergo chronobiologic evaluations. The chronobiologic evaluations will look at sleep and rest periods, activity as measured by a wrist monitor, and 24 hour inpatient electroencephalograph (EEG), rectal temperature, and melatonin monitoring.