Hypothesis
Every study begins with a research question to be answered. The question may have come following analysis of data from a previous experiment. It may similarly arise from the work of other investigators, as published in peer-reviewed journals. Based on the current body of knowledge, we can propose an explanation or predict an outcome for an event. These hypotheses will then be proven or challenged through experimentation.
Study design and experimentation
Once a hypothesis has been formulated, an experiment will be designed to test it. Here, the experimental questions lead to the design of an experimental protocol. Care is taken to carefully control sources of experimental biases. Researchers compete for public and private funds to cover the cost of experimentation. Scientific investigations in human or animals must adhere to strict ethical rules. All of our studies are reviewed by an institutional ethics board on a regular basis. Special care is taken throughout the experiment analysis and publication processes to protect the anonymity and confidentiality of all research participants.
Recruitment and welcoming participants in laboratory experiments
Once an experimental protocol has been approved, we begin our search for eligible participants. Recruitment criteria are typically strict and may vary significantly from study to study. Each potential candidate undergoes an informed consent procedure prior to the screening and research procedures. Studying human circadian rhythms implies particular conditions. To allow the careful control of the experimental conditions, most candidates enrolled in our laboratory investigations will be asked to maintain a very strict sleep/wake schedule during several weeks prior to being admitted to a time isolation room.
Experimental period
The nature and the duration of the experiment depend on the experimental question being addressed. The presence of research personnel is required to ensure compliance with experimental procedures and ethical rules. They should also guide the participants and, in collaboration with a physician, ensure their safety and their physical and psychological well-being. During the study, participants will be asked to provide different types of data. They may provide biological samples that can be dosed for their concentration of certain hormones of interest like melatonin and cortisol. Sleep monitoring using standard polysomnography is often performed. Tests and questionnaires will also be completed by the participants to measure different parameters such as mood, alertness and performance.
Field experiments among workers
Several field studies are underway in workers on rotating schedules. The latter come from several industries. After a rigorous screening procedure and informed consent, workers will wear an ambulatory device to document their sleep-wake cycle (e.g. actigraphy). They will complete a daily electronic diary for several weeks to document their sleep schedule, fatigue and performance levels. They will collect various biological samples.
Data analysis and publication
Once an experiment is complete, the research team performs analysis of the data collected in light of the formulated experimental hypotheses and scientific evidence. Ultimately, the results of a research investigation, whether positive or negative, will be shared with the scientific community via publication in peer-reviewed journals and at international conferences.