Submaximal exercise testing to assess the anaerobic threshold in neuromuscular diseases

The anaerobic threshold (AT), a submaximal direct marker of aerobic fitness, is used for exercise intensity prescription in the healthy population and other chronic diseases, and may also be useful in NMD. The AT is used as an intensity target which distinguishes between low- and high intensity exercise zones, enabling individuals to exercise in tailored heart rate zones. However, the feasibility and reliability of the AT assessment through submaximal exercise testing in slowly progressive NMDs is not yet known. Further, a major disadvantage of conventional assessment of the AT is that it is a complex and lengthy procedure requiring expensive respiratory gas analysis equipment, and is not readily available in all healthcare settings. Therefore, the next innovative step is to develop a predictive model to easily determine the AT in NMD, i.e. without the use of expensive gas analysis equipment.

The study objective is (1) to determine whether the AT can be identified in individuals with slowly progressive NMD through submaximal exercise testing with respiratory gas analysis, (2) to determine the reliability of the AT assessment in individuals with slowly progressive NMD through submaximal exercise testing with respiratory gas analysis, and (3) to develop a predictive model using easy to measure variables to indirectly assess the AT through submaximal exercise testing without respiratory gas analysis in individuals with slowly progressive NMD.

We hypothesize that the assessment of the anaerobic threshold through submaximal exercise testing is feasible and reliable in NMD. Furthermore, we hypothesize that we will be able to develop a valid predictive model to determine the anaerobic threshold using indirect, easy to measure variables.

Participants will complete three testing days, separated by a minimum of three days. On the first and second testing day, two submaximal exercise tests will be performed, one with and one without respiratory gas analysis. On the third testing day, a maximal exercise test with respiratory gas analysis will be performed.

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