Sunday, October 7, 2012

Clinical Exercise Testing in CFS/ME Research and Treatment

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With thanks to Tom Kindlon

a Path Through the Valley

Clinical exercise testing in
CFS/ME research and treatment

Posted on October 4, 2012 by Lydia

This is a summary of the (rather long) lecture from
the CFIDS conference in Sweden this week;
"Clinical exercise testing in CFS/ME research and
treatment" (

I have omitted a lot of the discussion on the
advantages/disadvantages of various scientific
methods etc. and stuck mainly to the items that I
would assume a non-scientific interested person
would wish to know.

If you're of a scientific bent, you would probably get
more benefit from watching the actual lecture. All
credit to Professor Christopher R Snell of the Pacific
Fatigue Laboratory, California (USA).

If you're a sufferer, I recommend watching from
54:00 through to 59:20 – they go through a brief
summary of energy conserving techniques, which
could be very useful! Following this there is a case
study of how they applied some of these
techniques to a 17 year old sufferer to allow her to
manage the condition better.

Clinical exercise testing in CFS/ME
research and treatment: A summary

On an exercise test where a person has to exercise
until they are exhausted, a healthy person will
recover usually within a day, definitely within 48
hours (on the outside).

When they did this with CFS patients, they had only
one person recover within 48 hours – the average
recovery was 4 days.

CFS patients also had symptom flares as a result of
this test.`

There are problems with the PACE trial:

* they very selectively reported results

* they only took high-functioning CFS patients

* they used the 6-minute walking test (see below)

* patients at the end of the trial, were still walking
at a severely disabled speed, even when they had
improved the distance they could walk. If a patient
who needed a heart transplant could only walk this
speed due to a lung problem, they would not be
allowed onto the transplant list because they
would not be deemed well enough to actually

* there is no mention of any improved functioning
in any other area for any of the trial participants

There are problems with the 6-minute
walking test (as used in the PACE trial
as a measure of functioning) and other
similar tests

* they assume that the patient does not exercise
to exhaustion, or anywhere near exhaustion. All
the understanding of the results are based on the
assumption that it was just a casual exercise
experience that they could easily repeat.

* it does not work for specific groups of unhealthy
people, it is designed only for a healthy population,
so results from an unhealthy group can't be
interpreted validly. This is because they rely on
the heart rate as a measure of energy production,
but the way the heart rate and energy production
are linked in a healthy person is not necessarily the
same in a sick person. Many studies in fact show
that the link between them in certain diseases is
very different – meaning you cannot rely on these
tests in sick individuals, without first carrying out
studies to determine what the connection is.

* the american heart association says not to use
tests with heart-rate measures, as many people
use heart-rate controlling medication (eg: for
POTS, migraines)

The best way to assess physical
function is to use

"cardio-pulmonary exercise testing", which is to

* oxygen consumption (as oxygen is used directly
to produce energy, this will always be a correct
measure). This is effected by lungs, heart and

* the "anaerobic threshold" – which is the point at
which the carbon dioxide you breathe out is
greater than the oxygen you take in. In a healthy
person this is 50-60% of max. oxygen
consumption; in an athlete it may be as high as
90%. In CFS patients it is very very low, and going
above it makes you worse – and is very easy to do

* you can prove beyond doubt that someone is not
faking these results because you are measuring
the amounts of oxygen and carbon dioxide in the
air they breathe in and out.

* you can establish beyond doubt that the persons
capabilities in the test have nothing to do with
motivation/effort because the "effort" of the
person is shown in the oxygen intake/carbon
dioxide given out

* these are a good measure of function, they are
very reliable and accurate

* there are alreasy established measures of this for
many other healthy people and disease states,
meaning you can compare ME patients to others

Exercise will not cure ME/CFS. But – people who
do not exercise will suffer the effects of a
sedentary lifestyle, so if you can do some
exercise without making symptoms worse, it is
probably beneficial to do so

Post exertional malaise occurs across all the
spectrum of ME/CFS patients – regardless of how
severe they are

It does not show up in an single exercise test – you
need to test again (they do it 24 hours later). This
allows them to measure the post-exertional effect.
(Many ME/CFS patients could be assessed as
normal on a single test, due to eg: having rested
beforehand, it is the second test which shows they
are ill)

It is hard to separate the effects of deconditioning
from the effects of CFS with a single test

* but with multiple tests you can see what CFS has

At 37 minutes there is a table of results for ME

The second test shows:

* ME/CFS patients do worse on the second test;
they are significantly worse (in terms both of
workload they accomplish, and the
oxygen/anaerobic measures)

* non-ME/CFS patient will improve on the second
test (graph at 42mins).

* ME/CFS patients have a drop in the oxygen
consumption, but a much much worse drop in the
amount of work actually achieved. This shows that
the exercise on the second test is less effcient

* the drop in peak-oxygen consumption is actually
less for severe patients than for milder patients;
but severe patients start out with a much lower
oxygen consumption than a milder patient.

* the drop in workload done is more in severe
patients than milder patients

* The theory is that there is a basic level of oxygen
consumption that you need to survive, and the
more severe you are the closer you are to this
base level. So severe patients cannot drop any
lower or they would die, so they reduce workload

This is a reproducable, reliable test which shows the
extent of the post-exertional malaise; other
research groups have replicated these results

Their tests show objectively for CFS patients:

* an atypical recovery

* an abnormal stress-test

* post exertional malaise

There are many theories as to why post-exertional
malaise occurs

Their research shows ME/CFS patients

* have a reduced physical working capability

* the aerobic energy generation (the production of
energy in the presence of oxygen) is impaired

* activity exacerbates symptoms ( every ME/CFS
patient has post exertional malaise)

Their research can be used as an objective
proof of disability (for example, for disability
assessments and clinical trials)

It is quantifiable – ie: it can measure accurately to
a degree how ill the patient is

It reveals abnormality across many systems

Cognitive behavioural therapy is not a cure for
ME/CFS – but it can be useful to help patients
manage/adjust to their illness

ME patients can go a very long way into the
anaerobic threshold (longer than most people
manage) because they have adjusted to being ill;

but this results in huge PEM. So short-term,
patients can often manage a lot more than they
can manage long-term.

Avoiding activities above the anaerobic
threshold will help patients avoid PEM

* heart rate monitors can help; they are set to go
off just before you hit the anaerobic threshold, to
get you to rest instead of using too much energy

* activity logs can help; you can identify activities
which make you worse (what activities make you
ill? How do you feel the next day? Do you get PEM?
Can you carry out other normal activities and
these activities?)

* "rates of perceived exertion" can help; this is a
fancy way of saying, if it feels like a lot of effort, it
is a lot of effort – stop!

Resting will help recovery from going into the
anaerobic threshold

If you go above the anaerobic threshold, you will
have to pay back far more energy

Physiotherapy can help – but physios often need to
be re-trained to understand ME/CFS

* reconditioning will not work with ME/CFS patients

They have a therapy called "energy
conservation therapy" – I think this is basically
working out how to manage your life now with
less energy. It involves

* pacing

* body positioning (ie: sit instead of stand to use
less energy)

* protecting joints

* using assistive devices

* planning activities (to make sure you don't

* using any energy saving thing you can do etc.

They also have a "theraputic exercise program"
(nothing like GET!) – this can be aided by
trained physios

* learning to breathe properly

* training the anaerobic system, not the aerobic

* exercise must be recovered from within 24 hours
– if you take longer than that to recover, it is
harming you, not helping

* stretching

* only doing a little bit at a time

* only ever increase amounts if you aren't
experiencing symptom increase – decrease
amounts if you experience symptoms

He closed with the comment:

"It doesn't really matter what you call it, there
are hundreds and thousands of people who are
really really sick; if the medical profession is
not helping them, their government
representatives are not helping them; they
need help urgently."


Jill Gates said...

Hi - we replied late to a post and think maybe comments aren't checked when they go back too far. Thought we might try our request again on a newer post. Again, thank you.

"Would be very interested in the studies/reports placing physicans as being the #3 cause of mortality to patients. Could you cite them for us? Thank you in advance. J.G. RN"

CFS Facts said...

The statistics can be easily googled. I'm sure some of the studies are linked to in other posts in this blog. I know one source of the statistic was