Living with Chronic Pain

What Is Post-Exertional Malaise?


Post-exertional malaise (PEM) is one of the symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Common symptoms of ME/CFS include severe fatigue, brain fog, weakness, muscle pain, and headaches. With PEM, these symptoms worsen after exertion.


Exertion typically brings to mind physical activity; however, physical activity is not the only cause of PEM. Mentally or emotionally draining tasks, social activities, or daily tasks, such as taking a shower or cooking a meal, can also trigger post-exertional malaise.


With PEM, worsening of ME/CFS symptoms typically occurs 12 to 48 hours after physical or mental exertion and can last for days or weeks. Recovering from a period of PEM often requires complete rest in a quiet, dark room.

Managing PEM requires balancing rest with daily living activities, social occasions, and school, work, or other obligations. Balancing activities and rest in a way that helps prevent or limit symptoms of PEM can help, but it can also occur unexpectedly.

Some level of physical activity is still necessary when dealing with PEM to prevent deconditioning of the cardiovascular system and muscles. However, standard physical activity recommendations for healthy individuals can be harmful to individuals with PEM. Working with a rehabilitation specialist or an exercise physiologist who understands ME/CFS may help improve function while also preventing setbacks.

Did you find this helpful?
You may also like