Fatigue - an overwhelming tiredness - is one of the most common symptoms of MS.
Some people find that it is the symptom that affects them most, but there are ways to manage it and minimise its effects on your life.
Fatigue in MS is not just an ordinary tiredness, like you might get at the end of a hard day's work. It's as an overwhelming sense of tiredness that often occurs after very little activity.
Fatigue affects people in different ways, and it may change daily or hourly. This can make it complicated to explain your fatigue to others.
Some research suggests that fatigue might be caused by the way that the brain adapts to the impact of MS.
Brain scans of people who have fatigue show that they use larger areas of the brain to carry out activities than other people.
Fatigue may be caused by the effects of MS on the central nervous system, but other things - heat, side effects of drugs, or other MS symptoms - may play a part.
There may be changes that you can make to minimise your levels of fatigue. Making sure you get proper rest, scheduled into your day, as well as learning to prioritise key tasks, can make fatigue easier to manage.
Combining sensible exercise with a balanced diet can help you maintain a healthy weight and get the energy you need. Some drug treatments can also help fatigue.