Having ME/CFS has a significant impact on educational and employment opportunities and social and family life because people with ME/CFS are simply not well enough to participate fully.

Much sleep is often needed in the acute, early phase of ME/CFS. It is not uncommon for people to spend 18 -23 hours of the day in bed either asleep or trying to sleep and the rest of the time on the couch.

This situation generally improves over time such that there are often periods during the day when they feel a little better and are able to engage in some form of activity, even if very limited. After relatively little physical and/or mental exertion they start to experience a worsening of symptoms, often in a sequence unique to themselves, and will take a disproportionate amount of time to regain pre-exertion levels of function, often 24 hours or more. The onset of the post-exertional malaise can also be delayed, sometimes several days. The amount of activity that can be undertaken before symptoms worsen varies from person to person.

Most find that climbing stairs and slopes, walking far, heavy lifting, bending, standing still, sitting upright for long periods, driving distances, repetitive actions (chopping vegetables, brushing hair), long conversations and mental activity exacerbate symptoms.

Many require help with transport, shopping and household chores and, for some, ordinary tasks of personal care such as showering and dressing may be more than they can manage without feeling worse - resting or going back to bed after washing and dressing is a common occurrence. The more severely affected require a wheelchair and others are bedridden for months or years and dependent on others for all care.