Medical Matters > Functional Limitations: Energy

ME Essential Summer 2020


I have a diagnosis of both ME/CFS and fibromyalgia. For the last couple of months I get a weird thing happening. I can be fine one minute but the next I struggle to keep my eyes open. It’s as though someone has drained all the energy out of my body and I usually end up falling asleep for a few hours. I don’t even have to have done anything but just sitting in my chair. Is this normal for ME/CFS? Or is it something else?


The simple answer to your question is no. A sudden loss of energy that occurs regularly leading to an inability to keep your eyes open is not normal in ME/CFS – especially if there is no obvious triggering factor (e.g., overactivity) to these episodes. Although people with ME/CFS do occasionally report a sudden deterioration of symptoms for no obvious reason, this should not be regarded as a characteristic or diagnostic feature of ME/CFS.

This is because there are other conditions – that can cause a sudden drop in energy levels with muscle weakness and a need to sleep – which need to be considered and excluded in a situation like this. Two immediate, although rare, examples that come to mind are narcolepsy and myasthenia gravis – both of which are sometimes misdiagnosed as ME/CFS.

By coincidence, I have recently been dealing with someone whose muscle weakness did not really fit with her current diagnosis of ME/CFS. On further investigation, the diagnosis turned out to be myasthenia gravis.

This is something that you really must talk to your doctor about – who can refer you to hospital for further assessment and investigations if necessary.

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Medical Matters is for information purposes only. The answers provided by Dr Shepherd and the ME Association’s other expert advisers should not be construed as medical advice. We recommend that any information you deem relevant is discussed with your GP as soon as possible. It is important to obtain advice from a GP who is in charge of your clinical care, who knows you well, and who can consider other likely causes for symptoms. Seek personalised medical advice whenever a new symptom arises, or an existing symptom worsens. Don't assume that new or worsened symptoms are a result of having ME/CFS.

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