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Completed

NCT Number: NCT04097886

Timed Exercise Study

The purpose of this study was to investigate the effect of timed exercise on human circadian rhythms. Subjects were randomized to 5 days of morning or evening treadmill exercise. A measure of internal circadian timing, or phase, was measured at baseline and following the exercise intervention. Change in circadian phase was compared between the morning and evening group.

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Key information

Conditions

Circadian Timing - Exercise Behavior Motor Activity

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Kentucky

Lexington, Kentucky, 40536, United States

About this study

This study investigated the effect of morning versus evening exercise on internal circadian timing, or phase. Young, sedentary subjects were recruited for this study. Baseline measures included anthropometric, body composition, cardiorespiratory fitness, chronotype, and circadian phase. Subjects were randomized to 5 consecutive days of morning or evening exercise. Thirty minutes of exercise was performed at the designated time and intensity was maintained at a heart rate corresponding with 70% peak VO2. The measure of circadian phase was salivary dim light melatonin onset, indicated by the time when saliva melatonin concentration exceeded 4pg/ml. Post-exercise circadian phase was measured the evening following the last day of exercise. Changes in circadian phase were compared between morning and evening groups.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • BMI 18.5-40.0
  • sedentary; <=2 hrs structured exercise weekly
  • medication free (other than birth control)

Exclusion criteria

  • diagnosed conditions that would contraindicate safe participation in physical activity
  • diagnosed psychiatric conditions
  • night or rotating shift work 1-year prior to study
  • travel across time zones within previous 4 weeks
  • having children <2 years of age
  • smoking

Treatment and study plan

Morning Exercise

Other

moderate intensity exercise (70% VO2 max) each morning for 5 days

Evening Exercise

Other

moderate intensity exercise (70% VO2 max) each evening for 5 days

Primary outcomes

  1. Change in onset (time) of melatonin secretion

    Time frame: baseline and following completion of exercise intervention (approximately 5 days)

    Difference in onset (time at which salivary melatonin exceeds threshhold; 4pg/mL) from baseline to completion of exercise intervention.

Sponsors and collaborators

Lead sponsor

Julie Pendergast

Other

Registry information

Official study title

Investigating the Effects of Timed Exercise on Human Circadian Rhythms

Important dates

Study start
2017
Primary completion
2019
Study completion
2019
First posted
Sep 20, 2019
Registry last updated
Sep 20, 2019

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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