Effects of Light and Exercise on Human Circadian Rhythms and Performance

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT02747719

Enrollment

Registered

2016-04-22

Start date

2016-04-30

Completion date

2018-05-31

Last updated

2018-07-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Circadian Rhythm

Brief summary

Both light and exercise are effective countermeasures for space and ground-based crews for circadian phase resetting and alertness levels. The investigators propose to test the combined effects of these two countermeasures to determine whether adding exercise to light stimuli will further improve circadian phase resetting and alertness.

Interventions

BEHAVIORALLight and exercise

Exposure to light and exercise

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 55 Years

Healthy volunteers

Yes

Inclusion criteria

* healthy by history, physical exam, laboratory studies of blood and urine, and psychological screening * moderate-intensity exercise for at least 150 minutes per week

Exclusion criteria

* color blind * no prescription medications, except hormonal birth control in females

Design outcomes

Primary

Measure	Time frame	Description
Circadian Phase	8 days	Circadian Phase will be measured using the change in timing of the melatonin rhythm on different days of the protocol. Melatonin will be assayed in blood and/or saliva.

Secondary

Measure	Time frame	Description
Subjective alertness	8 days	Subjective alertness will be measured using the change in values on standardized mood scales on different days of the protocol.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026