Diagnosis There's no single test to confirm a diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Symptoms can mimic those of many other health problems, including: Sleep disorders. Fatigue can be caused by sleep disorders. A sleep study can determine if your rest is being disturbed by disorders such as obstructive sleep apnea, restless legs syndrome or insomnia. Other , Ongoing fatigue affects quality of life and state of mind. Most of the time fatigue can be traced to one or more lifestyle issues, such as poor sleep habits or lack of exercise. Fatigue can be caused by a medicine or linked to depression. Sometimes fatigue is a symptom of an illness that needs treatment., If you have a difficult time staying awake and alert during the day, you may be experiencing excessive daytime sleepiness. Dr. Virend Somers, a Mayo Clinic cardiologist with a focus on sleep medicine, explains the difference between being tired and being sleepy and how excessive daytime sleepiness can have a negative effect on the heart., Most people with cancer have fatigue. Find out what cancer-related fatigue feels like and when it's concerning. Learn ways to cope with fatigue., At my recent chemo teach they explained that the fatigue and recovery will follow a pattern and you will be able to predict what days will be good or bad and be able to make plans accordingly. There's a lot of information and I found it overwhelming the first time., Sleep disorders also can affect mental health. And ongoing insomnia can raise the risk of suicidal thoughts and behavior. Sleep disorders can affect your quality of life. Excessive daytime sleepiness can make it hard to focus and pay attention. This can impact driving safety, workplace errors and how well you do in school..