Influence of Melatonin on Cardiovascular and Thermoregulatory Responses to Stress

Not Applicable

Recruiting

• Conditions: Stress; Mental Stress

• Registration Number: NCT07138443
• Lead Sponsor: Baylor University

Brief Summary

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.

Detailed Description

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 Timeline

• Status Verified: 2025-08
• Study Start: 2025-08-01
• Study First Submitted: 2025-08-11
• Study First Submitted QC: 2025-08-21
• Last Update Submitted: 2025-08-21
• Study First Posted: 2025-08-22
• Last Update Posted: 2025-08-22
• Primary Completion: 2026-08
• Study Completion: 2026-08-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 20

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Heart Rate Reactivity	4 weeks	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.
Blood Pressure Reactivity	4 weeks	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.
Distal-to-Proximal Skin Temperature Gradient	4 weeks	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.

Secondary Outcome Measures

Name	Time	Method
Perceived Stress and Coping (Likert Scale)	4 weeks	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.
Karolinska Sleepiness Scale	4 weeks	The Karolinska Sleepiness Scale will be used to assess participants' reported sleepiness prior to stress task initiation. The scale ranges from 1 (extremely alert) to 10 (Extremely sleepy, can't stay awake) to measure momentary levels of sleepiness.
Salivary Melatonin	4 weeks	Saliva will be sampled 45 minutes after melatonin or placebo ingestion. This will be used to quantify salivary melatonin between conditions.

Trial Locations

Locations (1)

Baylor University Autonomic Function Laboratory; 🇺🇸 Waco, Texas, United States