Fatigue and Weakness
According to National Multiple Sclerosis, 80% of people with MS have fatigue. MS-related symptoms tend to worsen as the day goes on, and it is often aggravated by heat and humidity and comes on more easily and suddenly than normal fatigue. Weakness can develop due to muscle atrophy (muscle shrinking due to not being used) or demyelination of the nerves. Fatigue is often related to the number of lesions in the brain and inflammation.
Chronic fatigue happens when nerves deteriorate in the spinal column. Most time, fatigue appears suddenly and lasts for two weeks before improving. A person can also experience intermittent, recurrent, or constant chronic fatigue with MS.