Why am I always tired? 22 medical reasons for feeling tired

Sleep Disorders

Daytime sleepiness is a key feature of obstructive sleep apnea.However, sleepiness and fatigue are not the same. Sleepiness is the inability to remain fully awake or alert during the day while fatigue is a subjective lack of physical or mental energy interfering with daily activities.Nonetheless, people with sleepiness due to obstructive sleep apnea use terms like fatigue, tiredness, and low energy to describe their symptoms.