When I first started M.E advocacy back in 2014, I didn’t spend much time thinking about severity levels. I knew the basics, mild, moderate, severe, very severe, and I learned the familiar statistics that charities and research groups have used for years: around 25% mild and 25% severe or very severe. Those numbers have stayed remarkably stable, even as our understanding of M.E has grown.

But recently, especially after my foggy‑brain posts yesterday, I’ve been thinking more deeply about what Moderate M.E actually looks like. Not according to one organisation’s definition, but according to the shared core of the three major severity scales we rely on: the International Consensus Criteria, the ME Association, and NICE.

Because moderate M.E is where half of our community lives, and yet it’s the severity level we talk about the least. It’s often the bit we pass through as we ‘improve’ or ‘get worse’.

When you strip away the differences between the International Consensus Criteria, ME Association, and NICE’s severity scales, a clear, shared picture emerges. Moderate M.E is a severity level where symptoms significantly restrict daily life, mobility, cognitive function, and independence. It is long‑term, life‑altering, and unpredictable.

Here’s the neutral, combined definition (created/merged by me), the part all three frameworks agree on:

Moderate M.E is a state where daily life is significantly restricted. People can perform some essential tasks, such as basic personal care, short walks, or simple meal preparation, but only with major adjustments, rest periods, and trade‑offs. Mobility is reduced, cognitive function is impaired, and post‑exertional malaise occurs after even small activities. Work or education is usually no longer possible. Symptoms fluctuate, creating ‘better’ days and ‘worse’ days, but the overall impact is substantial, long‑term, and life‑altering.

Here’s what that can look like in everyday life:

• Showering may be possible, but often requires lying down afterwards.
• Preparing a simple meal might be manageable, but eating it sitting upright can be difficult. (Note to my parents: this is why I am ALWAYS the first down from the dinner table!)
• Light household tasks are possible; heavier ones are not.
• Walking short distances is doable, but stairs or longer outings may require aids or recovery time.
• Conversations, reading, or decision‑making can be challenging due to cognitive dysfunction.
• Daily rest, often lying down, is essential.
• PEM is triggered by small activities and can last days or weeks.
• Social life shrinks dramatically.
• Planning becomes difficult because ability fluctuates.

This is moderate M.E, the missing middle of M.E advocacy.

One thing all three frameworks emphasise is that M.E severity is fluid. People move up and down the spectrum over time. Some of us improve, some of us worsen. Some hover between levels and never feel like they fit neatly into any definition.

I’m one of them.

Over the past six years, I’ve worsened due to multiple COVID19 infections. I now sit at the low end of moderate M.E. I’m still able to work, but only 16 hours per week at most, and often far less, depending on fluctuations. Some weeks I can manage those hours, other weeks I can’t. Some days I can do a little more, some days I can do nothing at all.

That’s the reality for many people with M.E: we don’t fit perfectly into any severity box.

Some of our symptoms are worse than other people’s. Some are milder or others have symptoms we don’t have. Some don’t experience the same wider range of symptoms we do (outside the diagnostic criteria).

But one thing is universal across all severity levels: PEM is a certainty. It is the defining feature of M.E, and it shapes every decision, every activity, every day.

As stated above, there are multiple severity scales, including the ICC, MEA, NICE,  and none of them will ever capture every individual’s experience. M.E is too varied, too complex, too fluid, and without a biomarker, we rely on self‑identifying data, charity surveys, and research‑led questionnaires.

Many people with M.E aren’t counted at all: those who are very mild and ‘just don’t feel right’, but don’t know what is wrong, those who have no diagnosis, those who have been misdiagnosed, those who are too sick to participate in research, those without internet access, and those who are isolated or unsupported.

So the numbers will never be perfect. But we have to work with what we’ve got, and what we’ve got consistently shows the same thing:

Moderate ME is the most common lived experience of ME.

It’s time we talked about it more.

M.E. Foggy Dog will keep advocating for all severity levels, especially the majority living in the middle.

Here’s a vlog I recorded this morning on this subject. For those of you who prefer a transcript, it’s included on the YouTube post.