Marek has been studying a new service that is rapidly growing in the Czech Republic called the ?Dark Therapy,? which he recognized as a form of Chamber REST. His first data collection ran from 2010-2013, and was conducted with 37 customers signed up for Dark Therapy at the Beskydy Rehabilitation Center in ?eladná. The data was mainly collected after seven-day long stays in conditions of absolute dark, silence, and solitude, using questionnaires and surveys including the Existence Scale, the Five Facets Mindfulness Questionnaire, the Rosenberg Self-esteem Scale and The Symptom Checklist 90. His most recent study began in early 2015, and is still in progress. It involve university student volunteers who participate in 2-3 day Dark Therapy sessions at a local facility. The study is focusing on the differences in a battery of cognitive performance tests, and on physiological data such as EKG, HRV and hematocrit.