PBM Effects on Health and Well-being in Humans

The goal of this clinical study is to assess the effects of different photobiomodulation (PBM) conditions in men and women between 25 and 65 years old with daytime sleepiness/drowsiness and /or mild mood complaints but be otherwise healthy. The main question it aims to answer are: 1. Does PBM significantly affect health and well-being? 2. Are PBM effects wavelength dependent? 3. Are PBM effects pulse dependent? 4. Are the eyes needed to assert an PBM effect or is exposure only to the skin sufficient? 5. What are the cellular, metabolic pathways underlying the systemic effects of PBM. Participants will have to: 1. Exposed themselves 5 times per week during 2 weeks to the PBM stimuli between 9:30 and 12:30. 2. A week before the baseline measurement, participants will have to start wearing a Fitbit Versa 3, and will have to continuously wear until the end of the study. 3. In the afternoon of the baseline day as well as in the afternoons after 5 and 10 PBM sessions (week 1 and week 2, respectively), participants will have to go to the lab for blood withdraw. 4. In the evening of the baseline day as well as in the evenings after 5 and 10 PBM sessions (week 1 and week 2, respectively), participants will have to collect saliva samples as well as to complete questionnaires. It will be a double-blind placebo-controlled field study with a between subject comparison.