Influence of Melatonin on Cardiovascular and Thermoregulatory Responses to Stress

Baylor University16 enrolled

Overview

This study aims to evaluate the influence of acute oral melatonin supplementation on cardiovascular and skin temperature responses to mental stress. The hypothesis is that acute melatonin will lead to reduced cardiovascular and skin temperature responsiveness to acute mental stress.

This study will utilize a randomized, crossover, placebo controlled experimental approach to determine the effects of acute oral melatonin supplementation (3mg) on blood pressure, heart rate, and regionalized skin temperature responsiveness to mental stress. The study will assess beat-by-beat blood pressure (finger plethysmography), continuous heart rate (electrocardiogram), and proximal/distal skin temperature continuously at rest and in response to the Trier Social Stress Test following either afternoon melatonin or placebo ingestion in a randomized order. Participants will consist of young healthy adults.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Enrollment

Conditions

Stress Mental Stress

Interventions

Melatonin 3 MG Oral TabletDIETARY_SUPPLEMENT

Participants will ingest an acute 3mg oral melatonin tablet

Placebo Oral TabletDIETARY_SUPPLEMENT

Participants will ingest a placebo tablet (sugar pill) of the same size, shape, and color of the active melatonin supplement

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Must be between the ages of 18-70 years old. * All subjects will be required to abstain from exercise and caffeine for 12 h, and alcohol for 24 h prior to the experiment. * BMI must be \<30 kg/m2. * Menstruating women will initially be tested during their early follicular phase (2-5 days after initiating menstruation) or during low hormone phase (2-5 days after initiating menstruation) if on oral contraceptives to control for potential impact of sex steroids. Post-menopausal females (\>5 years) will also be included. Females must have an intact uterus and at least one ovary. Use of hormonal replacement therapy will be allowed. Exclusion Criteria: * Circadian rhythm sleep disorders * High obstructive sleep apnea diagnosis determined by STOP-BANG. * History of meeting Diagnostic and Statistical Manual of Mental health (DSM-V) criteria of major psychiatric disorder * Unstable or serious medical conditions (heart failure, diabetes, cardiovascular disease, etc.) * Current, or use within past month, of psychoactive (other than stable treatment with antidepressant), hypnotic, stimulant or analgesic medication (except occasional non-narcotic analgesics), beta blockers, or alpha blockers * Shift work or other types of self-imposed irregular sleep schedules * Habitual smoking (6 or more cigarettes per week) * Habitual alcohol consumption (more than 2 alcoholic drinks per day) * Pregnancy or breast feeding

Locations (1)

Baylor University Autonomic Function Laboratory

Waco, Texas, United States

Outcomes

Primary Outcomes

Heart Rate Reactivity

Heart rate will be continuously monitored using electrocardiogram during a 10-minute baseline and in response to the Trier Social Stress Test. Heart rate reactivity during the stress will be quantified.

Time frame: 4 weeks

Blood Pressure Reactivity

Beat-by-beat systolic, diastolic, and mean arterial pressure will be assessed using finger plethysmography in response to the Trier Social Stress Test. Reactivity scores will be assessed by determining the difference in blood pressure during the stress task relative to baseline.

Time frame: 4 weeks

Distal-to-Proximal Skin Temperature Gradient

Skin temperature will be monitored using small temperature sensors (iButtons, type DS1922L; iButtonLink LLC) adhered to various distal and proximal regions of the body. Upper distal to proximal skin temperature gradients (DPG) will be calculated as the average skin temperature taken from the hand subtracted from the average skin temperature taken from the forearm/shoulder. Lower DPG will be calculated as the average skin temperature taken from the feet subtracted from the average skin temperature recorded at the calves.

Time frame: 4 weeks

Secondary Outcomes

Perceived Stress and Coping (Likert Scale)

Participants' stress and perceived coping will be monitored throughout the stress task in both experimental conditions. Participants will be asked to rate their perceived stress on a Likert scale ranging from 1 (not at all stressed) to 7 (extremely stressed). Participants will also be asked to rate how well they perceived their ability to cope with the demands of the tasks on a scale ranging from 1 (not at all able to cope) to 7 (extremely able to cope). The quotient of stress/coping will be operationalized as a measure of threat perception. A challenge appraisal is defined as a stress-coping ratio of ≤1 (i.e., coping ability meets or exceeds the perceived stress of the task) whereas a threat appraisal is defined as a stress-coping ratio \> 1 (i.e., perceived stress of the task exceeds coping abilities). Comparisons between conditions will be performed to assess the differences in numeric ratings of stress, coping, and threat perception measured in arbitrary units.

Data from ClinicalTrials.gov

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