Ultraviolet light exposure was shown to be able to release nitric oxide from the skin into the blood stream and lead to an acute decrease in blood pressure and increase in vascular function. Additionally, preliminary work indicates that UV free blue light also releases nitric oxide in the skin mediating similar effects as seen with ultraviolet light A(UVA). It is the goal of the present experimental study to investigate the hemodynamic effects of whole body blue light exposure including blood pressure, endothelial function and vascular stiffness. Therefore, healthy volunteers will be exposed to 30 minutes whole body blue light (453 nm wavelength) and the change in blood pressure and endothelial function (Flow mediated dilation (FMD)), heart rate, forearm-blood flow, forearm vascular resistance central blood pressure and vascular stiffness ( pulse wave analysis by sphygmocor) will be measured. In this randomized controlled cross-over study, 20 healthy subjects aged 30 to 60 years will participate.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
20
Subjects will be exposed to blue light (453 nm wavelength) for 30 minutes
Subjects will get control exposure to 30 minutes of whole body, which causes only comparable warming of skin as with blue light exposure.
Division of Cardiology, Pulmonary Disease and Vascular Medicine
Düsseldorf, North Rhine-Westphalia, Germany
Change of peripheral blood pressure
Change of peripheral blood pressure as measured before, during and up to 2 hours after 30 min blue light as compared to control
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change in endothelial function
measured by flow mediated dilation (FMD) before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline heart rate
measured by electrocardiography (ECG) before, during and up to 2 hours after 30 min blue light as compared to control
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline forearm blood flow
measured by ultrasound before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline forearm vascular resistance
measured by ultrasound before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline central blood pressure
measured by applanation tonometry before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline vascular stiffness
measured by applanation tonometry before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline NO-species
determined by chemiluminescence before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline Cortisol
measured before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
Change from baseline Endorphins
measured before, immediately after 30 min exposure and at 2 h thereafter
Time frame: baseline, during 30 min exposure and 2 hours thereafter
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