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Completed

NCT Number: NCT07138443

Influence of Melatonin on Cardiovascular and Thermoregulatory Responses to Stress

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.

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Key information

Conditions

Stress Behavior Behavioral Symptoms Mental Stress Stress, Psychological

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Baylor University Autonomic Function Laboratory

Waco, Texas, 76706, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Melatonin 3 MG Oral Tablet

Dietary Supplement

Participants will ingest an acute 3mg oral melatonin tablet

Placebo Oral Tablet

Dietary Supplement

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

Primary outcomes

  1. Heart Rate Reactivity

    Time frame: 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.

  2. Blood Pressure Reactivity

    Time frame: 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.

  3. Distal-to-Proximal Skin Temperature Gradient

    Time frame: 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 outcomes

  1. Perceived Stress and Coping (Likert Scale)

    Time frame: 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.

  2. Karolinska Sleepiness Scale

    Time frame: 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.

  3. Salivary Melatonin

    Time frame: 4 weeks

    Saliva will be sampled 45 minutes after melatonin or placebo ingestion. This will be used to quantify salivary melatonin between conditions.

Sponsors and collaborators

Lead sponsor

Baylor University

Other

Registry information

Official study title

Influence of Melatonin on Cardiovascular and Skin Temperature Responses to Stress: A Randomized Controlled Trial

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Aug 22, 2025
Registry last updated
Jul 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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