Modified Medical Research Council (mMRC) dyspnea scale: grades 0 to 4
The modified Medical Research Council (mMRC) dyspnea scale grades how much breathlessness limits everyday activity, from grade 0 at the mildest to grade 4, "Too breathless to leave the house, or breathless when dressing or undressing". Magent's calculator takes the grade as assigned and returns the grade and its wording, citing Mahler and Wells, 1988.
Not a medical device. Not a diagnosis or dosing recommendation.
What is the mMRC dyspnea scale?
Dyspnea means breathlessness. The mMRC scale describes it in terms of everyday activities rather than a measurement. Each grade is a short statement, and the person picks the one that matches their breathlessness.
The grades move from breathlessness with hard exercise, to breathlessness when hurrying or on a slight hill, to walking more slowly than others, to stopping for breath on the level, and finally to being too breathless to leave the house.
Magent's calculator doesn't question or examine anyone. It takes the grade, checks it is a whole number from 0 to 4, and returns the grade, the maximum of 4 and the matching wording.
The mMRC grades
grade wording
0 Breathless only with strenuous exercise
1 Short of breath when hurrying on the level or walking up
a slight hill
2 Walks slower than people of the same age on the level because
of breathlessness, or has to stop for breath when walking at
own pace on the level
3 Stops for breath after walking about 100 yards or after a few
minutes on the level
4 Too breathless to leave the house, or breathless when dressing
or undressingExact expression the calculator uses:
modified MRC (mMRC) grade 0-4 as assigned by the caller; Mahler 1988 (not Bestall MRC 1-5)Inputs
| Input | Meaning | Values |
|---|---|---|
mmrc | mMRC dyspnea grade, as assigned | 0, 1, 2, 3, 4 |
A value outside 0 to 4, or one that isn't a whole number, returns an error.
How the calculation works
- Take the grade as given. The calculator doesn't assess breathlessness itself.
- Check it. It must be a whole number from 0 to 4.
- Return the wording. The score equals the grade, and the description is the published wording for that grade.
Units
There are no units. The grade is a whole number. Grade 3 mentions a walking distance of about 100 yards as part of its wording.
Worked examples
These use Magent's own expected values for the calculator.
Example 1: the mildest grade
- Grade entered: 0.
- Score 0, maximum 4. Wording: "Breathless only with strenuous exercise".
Example 2: grade 2
- Grade entered: 2.
- Score 2. Wording: "Walks slower than people of the same age on the level because of breathlessness, or has to stop for breath when walking at own pace on the level".
Example 3: grade 4
- Grade entered: 4.
- Score 4, maximum 4. Wording: "Too breathless to leave the house, or breathless when dressing or undressing".
History of the mMRC scale
The calculator cites Mahler and Wells, Chest, 1988, a paper that evaluated clinical methods for rating dyspnea. The grade wording the calculator returns is the 0 to 4 wording given in the record for that source.
When it's used
The grade is recorded when breathlessness in daily life needs to be described in a standard way, for example in long-term lung conditions.
Who uses it
Respiratory clinicians, primary care teams and researchers record the grade, often by asking the person which statement fits.
Limits of the calculation
- The grade is chosen by the person entering it. The calculator doesn't check it.
- It describes breathlessness with activity. It doesn't measure lung function.
- It doesn't place anyone in a disease group or combine the grade with other measures.
- This page doesn't say what a grade means for a particular person.
Clinical decisions belong to a qualified clinician who knows the patient.
How it differs from related calculators
- BODE index adds points from BMI, airflow, a dyspnea grade and walking distance. The mMRC calculator returns the dyspnea grade by itself.
- CAT is a questionnaire with several items about the effects of a lung condition. The mMRC scale is a single grade.
Common mistakes
- Starting at 1. The mMRC scale runs from 0 to 4.
- Using a different MRC version. Check that the wording matches the 0 to 4 grades above.
- Entering a fraction. The grade must be a whole number.
Source
Mahler DA, et al. Evaluation of clinical methods for rating dyspnea. Chest. 1988;93(3):580-586. DOI: 10.1378/chest.93.3.580. PMID: 3342669
Frequently asked questions
What does mMRC stand for?
Modified Medical Research Council, as in the mMRC dyspnea scale.
What are the mMRC grades?
Five grades, 0 to 4, from breathlessness with strenuous exercise to being too breathless to leave the house.
Why does the scale start at 0?
The modified version numbers its grades 0 to 4. The calculator rejects values outside that range.
What is mMRC grade 3?
"Stops for breath after walking about 100 yards or after a few minutes on the level".
Does the calculator measure breathlessness?
No. The grade is entered, and the calculator returns its wording.