The prevalence of patients with obstructive sleep apnea (OSA) is high and increasing. Controlling OSA is an important issue for a medical domain. OSA adversely affects multiple organs and systems in individuals, with particular relevance to cardiovascular diseases. Patients with OSA have several signs and symptoms such as snoring, hypersomnolence, general fatigue, and cognitive impairment. Since OSA is a significant issue for a medical domain, many investigations on the pathophysiology of OSA have been conducted. Another important factor in the development of cardiovascular diseases and sleepiness is sleep duration. Therefore, an association between OSA and sleep duration has an impact on the development of cardiovascular diseases and other common diseases.