Exercise tolerance in patients diagnosed with ME/CFS
Investigators
Prof. Brian MacIntosh and Dr Eleanor Stein
Institution
University of Calgary, Alberta, Canada
Background, aims and methods
Post-exertional symptoms, including pain and ‘malaise’, are characteristic symptoms of ME, but objective ways of measuring these key symptom after exercise are lacking. This has consequences for patients since modern medicine likes to quantify complaints and tends to devalue or discount those it cannot. Yet, there is an urgent need to have objective, widely accessible tests for ME/CFS, and although physical exertion is difficult for people with ME/CFS, it has been suggested that repeat testing with a graded exercise test might show quantitatively that patients do not recover as quickly from this kind of physical challenge as would be expected. If this is the case, then dual graded exercise tests separated by 24 hours might indeed be a useful element in diagnosing the condition.
The pilot investigation, led by Prof. Brian Macintosh (Professor and Associate Dean of Kinesiology at the University of Calgary) and Dr Ellie Stein, will examine patients using the Canadian Consensus Criteria for ME/CFS (2003) as well as the standard 1994 CDC criteria, a basic assessment step which ME Research UK is requiring all its prospective grant-holders to undertake when assessing new study patients. Each subject will perform a symptom-limited incremental exercise test on an electronically braked cycle ergometer while connected to the metabolic cart through a mouthpiece, and effort in each test will be assessed from blood measurements of peak blood lactate concentration. The researchers’ hypothesis is that patients with confirmed ME/CFS plus post-exertional symptoms will have a decreased performance (as measured by maximum oxygen consumption) on an exercise test completed 24 hours after the first as compared with the initial test. By contrast, control subjects (matched for age and chronic activity level) will have similar performance on the two tests.
If successful, the pilot data could be key to a successful application for funding for a larger comprehensive study to better define, measure and differentiate the symptoms of patients with ME/CFS from those with other medical conditions.
