Influence of Caffeine Consumption on the Human Circadian System

• Status: Completed
• Trial end date: 2017-12-17
• Target enrollment: 0
• Participant gender: Male

Summary

Surveys indicate that 85% of the adult population consume caffeine on a daily basis. Caffeine acts on sleep homeostatic mechanisms by antagonizing the sleep factor adenosine. Whether and how caffeine also impacts on the circadian regulation of sleep and -wakefulness is fairly unexplored. This study quantifies the influence of regular caffeine intake and its cessation on circadian promotion of sleep and wakefulness, on circadian hormonal markers, well-being, neurobehavioral performance and associated cerebral mechanisms. The knowledge is expected to contribute important insights on recent societal changes in sleep-wake behavior (e.g., shorter sleep duration and delayed sleep phase) and the related increase in people suffering from sleep problems.

• Phase: N/A
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: Psychiatric Hospital of the University of Basel
• Collaborator: Swiss National Science Foundation
• Treatments: Caffeine; Mannitol

Criteria

Inclusion Criteria:

• Self-reported caffeine consumption: 300 mg - 600 mg daily

• 18-35 years old

• Healthiness

Exclusion criteria based on chronic or debilitating medical conditions:

Normal current health was established based on questionnaires, screenings of urine, and examination by the physician in charge. Given the wide range of illnesses encountered in medical practice, we only list those that were certainly reasons of exclusion:

• Diseases of somatic origin: Cardiovascular-, respiratory-, gastrointestinal-, hematopoietic- visual- and immune system diseases, kidney and urinary tract, endocrine and metabolic diseases, neurologic diseases, infectious diseases, allergies (e.g. skin allergies, acute hay fever), thrombocytopenia or other dysfunction of the blood platelets.

• Sleep disorders: Narcolepsy, sleep apnea (apnea index >10), periodic limb movements (PLMS >15), insomnia (polygraphically recorded sleep efficiency <70 %), hypersomnia, usual time in bed not between 6-9 h (assessed by [101]).

• Chronobiologic disorders: Hypernychthemeral sleep/wake cycle, delayed sleep phase syndrome (waketime >2 h later than desired, or habitually after 10 am), advanced sleep phase syndrome (waketime >2 h earlier than desired or habitually before 5 am).

• Drug/alcohol use, except caffeine: Volunteers must be drug-free (including nicotine and alcohol) for the entire duration of the study, with no history of drug (excluding caffeine) or alcohol dependency.

Exclusion criteria based on to the study requirements:

• Self-reported caffeine consumption: < 300 mg and > 600 mg daily (as estimated from mean caffeine content per serving of caffeine containing beverages and food)

• Body Mass Index (BMI) range: <18 and >26

• Participation in other clinical trials <3 months prior to study begin

• Shift work <3 months prior to study begin

• Transmeridian travel (>2 time zones) <1 month prior to study begin

• Extreme chronotype (Morningness-Eveningness Questionnaire <30 or >70)

• Inability to follow procedures

• Insufficient knowledge of project language (German)

Exclusion criteria based on MRI safety:

• Metallic prosthesis or metallic implants or non-removable objects on the body (e.g. splinters, piercings)

• Tattoos with larger diameter than 10 cm

• Tattoos above the shoulder area

• Claustrophobia

• Contraceptive coil