The Influence of Sleep on Cardiovascular Outcomes

Inclusion Criteria: * Ostensibly healthy men and women Subgroup study (chronic pain) * Satisfies diagnostic criteria for fibromyalgia according to the Widespread Pain Index - Symptom Severity (WPI-SS) scale with the following three conditions being met: 1. Widespread pain index (WPI) ≥7 and symptom severity (SS) scale score ≥5 or WPI 3-6 and SS scale score ≥9. 2. Symptoms have been present at a similar level for at least 3 months. 3. The patient does not have a disorder that would otherwise explain the pain. Exclusion Criteria: * No history of drug or alcohol dependency. * Must be current non-smokers, and are required to have a history of less than 5 pack years of smoking. * No history of working irregular day and night hours, regular night work, or rotating shift work for the 1 year prior to the study. In addition to this, individuals must not have traveled across more than 1 time zone during the 3 months prior to the study. * Chronobiologic and sleep disorders. * Diseases of the cardiovascular system. * Hypertension. Individuals will be allowed to be normotensive (resting systolic blood pressure of \<140/90 mmHg, measured on more than one occasion) or uncomplicated stage 1 hypertension (systolic BP between 140 and 159 mmHg or a diastolic BP between 90 and 99 mmHg). * Disorders of the respiratory system. * Pre-diabetes/Diabetes. For participants who have self-reported pre-diabetes/diabetes. * Disorders of the kidney and urinary tract. * Infectious diseases. * Disorders of the gastrointestinal system. * Disorders of the immune system. * Disorders of the hematopoietic system. * Neoplastic diseases. * Endocrine and metabolic diseases. * Neurologic disorders. * Must not be participating in another research study that would influence their safe participation in the study.