Benefits and Risks of Artificial Light Exposure: Characterisation of Effects on Alertness, Sleep, Cognitive Performance, Mood and Biological Rhythms

Inclusion Criteria: * Male or female * Aged 18 to 40 years * With a hint of Bodymass index (BMI) between 17 and 30 kg.m - 2 * healthy subject determined by a clinical examination, a psychological interview, a blood test, a urine analysis * Subject with a score\<6 questionnaire PSQI ("Sleep Questionnaire Pittsburgh") * Subject agreeing to maintain a regular sleep/wake rhythm during the study * Subject agreeing to refrain from caffeine, nicotine, alcohol, psychotropic drugs, cannabis or other drugs, during the study * Signed informed consent * Subjectaffiliated to a social protection scheme Exclusion Criteria: * somatic diseases: cardiovascular, respiratory, gastrointestinal, hematopoietic, Visual * immune system diseases * kidneys and urinary tract diseases * endocrine and metabolic diseases * neurological diseases * infectious diseases * thrombocytopenia or other malfunction of blood platelets * Subject with risk of thrombosis, including subject with a history of phlebitis, smoker under oral contraceptive... * Subject with an addiction to caffeine, nicotine, alcohol, psychotropic drugs, cannabis, or any other drug * Subject treatment contraindicated or inadvisable in combination with heparin * blood donation in the previous 3 months before the inclusion * Participation in other clinical trials * Work by shifts in the year preceding the inclusion * Trans-meridian travel (\> 2 time zones) in the month previous the inclusion * Impossibility to give enlightened information (subject in an emergency situation, understanding difficulties,...) * Subject under safeguard of justice * Subject under tutorship or curatorship * Pregnancy (women of childbearing age) * Breastfeeding * Diet incompatible with the study's snack choices