Exercise Stress Testing in Children with Metabolic or Neuromuscular Disorders

Abstract

The role of exercise as a diagnostic or therapeutic tool in patients with a metabolic disease (MD) or neuromuscular disorder (NMD) is relatively underresearched. In this paper we describe the metabolic profiles during exercise in 13 children (9 boys, 4 girls, age 5–15 yrs) with a diagnosed MD or NMD. Graded cardiopulmonary exercise tests and/or a 90-min prolonged submaximal exercise test were performed. During exercise, respiratory gas-exchange and heart rate were monitored; blood and urine samples were collected for biochemical analysis at set time points. Several characteristics in our patient group were observed, which reflected the differences in pathophysiology of the various disorders. Metabolic profiles during exercises CPET and PXT seem helpful in the evaluation of patients with a MD or NMD.

The Role of Moderate Aerobic Exercise as Determined by Cardiopulmonary Exercise Testing in ALS

“…Together with a respiratory compensation point (RCP) > 0.80 (see Table 3 ) in both evaluations and groups, it shows not only the existence of peripheral muscle underutilization of oxygen as described by other authors, but specifically a primarily impairment of muscle performance probably due to atrophy and loss of muscle bulk with a late increase in lactate and low VO 2 , exactly the opposite results for a mitochondrial myopathy with an early increase in lactate, combined with a very low VO 2 peak, as shown by Takken and colleagues, 2010 [ 36 ]. Likewise we recognized a primarily neurogenic impairment instead of deconditioning.…”

A Systematic Approach to Interpreting the Cardiopulmonary Exercise Test in Pediatrics

“…Muscle Metabolism Responses. When muscle metabolism or myopathies are suspected sources of limitations, a CPET can be helpful to unravel abnormalities (40). Parameters of interest during CPET include a reduced VO 2 peak, low VAT, and abnormally high or low blood lactate levels.…”

“…Finally, there is often a large VR because the demand on the respiratory system is usually relatively low. However, for diagnostic purposes, additional blood and urine samples should be collected before and after the CPET to measure lactate, ammonia, and creatine kinase among other metabolites (40). Abnormal RER values during progressive exercise and during recovery can also indicate metabolic abnormalities; for example, very high or low RER values during submaximal exercise could be indicative for a fatty acid oxidation disorder, mitochondrial myopathy, or glycogen storage disease, respectively (15,28).…”

Cardiopulmonary exercise test as a diagnostic tool in chronic diseases in children and adolescents

“…The literature also contains reports on the usefulness of the ergospirometric test in the assessment of the clinical status of patients with metabolic and neuromuscular disorders. CPET may be helpful in diagnosing the disease as well as prescription of appropriate physical activity [15].…”