The magnitude and duration of one’s fatigue, and the degree to which fatigue impairs daily activities will help distinguish CFS from ordinary fatigue. According to the criteria set by the Institute of Medicine (IOM) in 2015, one’s fatigue must feel profound, last for more than six months, and significantly reduce one’s ability to engage in daily activities compared to before symptoms began. Additionally, symptoms like extreme fatigue following exercise and the inability to get restful sleep are more characteristic of CFS than regular fatigue.