The Influence of Light Exposure on Exercise Performance Dependent on Chronotype.

Study Overview
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Brief Summary
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The purpose of this study is to determine if an exposure to light in the evening has a positive influence on physical performance regarding endurance, strength and reaction time.

Official Title
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The Influence of Different Light Exposures on Endurance Performance, Handgrip Strength and Reaction Time in Consideration of the Chronotype.

Conditions
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Endurance Performance, Reaction Time, Muscle Strength

Intervention / Treatment
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* Other: exposure to normal light
* Other: exposure to bright light
* Other: exposure to blue-enriched light


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: BMI 18 to 30 kg/m2 endurance performance >= 55 ml/min/kg peak oxygen uptake Exclusion criteria: cardiovascular disease renal dysfunction shiftworking travels over time zones in the last 4 weeks high blood pressure (systolic blood pressure >170mmHg, diastolic blood pressure >100mmHg) depression

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: bright light<br>Intervention: exposure to bright light | Other: exposure to bright light<br>* exposure to bright light for 60 minutes of duration<br>|
| Experimental: blue-enriched light<br>Intervention: exposure to blue-enriched light | Other: exposure to blue-enriched light<br>* exposure to blue-enriched light for 60 minutes of duration<br>|
| Experimental: normal light<br>Intervention: exposure to normal light | Other: exposure to normal light<br>* exposure for 60 minutes in duration<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Work performed in kilo Joule (kJ) during the time trial ergometer test adjusted for the VO2peak. | Participants will perform one baseline test (ergometer ramp test) and seven days later a twelve minute lasting ergometer time trial test which starts 10 minutes after an exposure to light for 60minutes. The work performed in kilo Joule during the time trial ergometer test will be assesed at the end of the time trial and will be the main outcome measure and adjusted for the VO2peak meausred during the baseline test. | The outcome measure will be assesed at the end of the 12minute time trial ergometer test. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reaction time in milliseconds (ms) | Participants will perform one baseline reaction time task 20 to 15 minutes before the light exposure. 0 to 5 minutes after the 60 minutes lasting light exposure they will perform the reaction task again. The time in milliseconds from the reaction task after the light exposure will be the secondary outcome measure and adjusted for the baseline test before light exposure. | Reaction time task will be performed at baseline (20 to 15 minutes before the light exposure) and 0 to minutes after the light exposure which will be the secondary outcome measure. | 
| Maximum handgrip strength in kilo gramm (kg) | Participants will perform one baseline maximum hand grip strength test 15 to 10 minutes before the 60 minutes lasting light exposusre and perform a second test, which will be the outcome measure 5 to 10 minutes after the light exposure. The strength in kg will be adjusted for the strength in kg measured at baseline. | Maximum handgrip strength will be tested at baseline (15 to 10 minutes before the light exposure) and 5 to 10 minutes after the 60 minutes lasting light exposure. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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circadian rhythm, light exposure, exercise capacity, endurance, strength, reaction