The Influence of HIIT Versus MCT on Cardiorespiratory Fitness in PPMS

The Influence of High-Intensity Interval Training Compared to Moderate Continuous Training on Cardiorespiratory Fitness, Symptom Improvement, and Disease-specific Biomarkers in Primary Progressive Multiple Sclerosis

Endurance training revealed to be an effective means to increase cardiorespiratory fitness in persons with Multiple Sclerosis (MS), considered relevant to health-related quality of life in this population. Moreover, endurance training improves MS-related symptoms, such as reduced walking capacity, fatigue, depression, and cognitive impairment. Owing to these benefits, endurance training has evolved as an integral part of MS rehabilitation, anchored in current treatment guidelines.

In recent years, High-Intensity Interval training (HIIT) evolved as a time-efficient and safe alternative to standard care in MS rehabilitation that is Moderate Continuous Training (MCT). Indeed, HIIT has already been proven superior to MCT in improving cardiorespiratory fitness, MS-related symptoms (e.g. cognitive impairment) and, beyond, seems to elicit disease-modifying effects on MS-pathophysiology (i.e. alleviated neuroinflammation and neurodegeneration).

However, current evidence is restricted to clinical trials that include samples with mixed MS disease courses, in which persons with primary progressive MS (PPMS) are underrepresented due to comparatively low prevalence rates.

Distinct pathophysiological mechanisms and symptom constellations prohibit the generalisation of previous findings to persons with PPMS. In this population, however, evidence-based rehabilitative strategies are urgently needed, as disability progression in PPMS is poorly responsive to pharmacotherapy.

This study, aims to validate previous findings on the superior effect of HIIT compared to MCT on improving cardiorespiratory fitness, MS-related symptoms and MS pathophysiology in persons with PPMS, contributing to the development of specific recommendations to maximize the effects of exercise as a potent non-pharmacological treatment adjuvant.

Inclusion Criteria:

• adult age (≥ 18 years)
• definite MS diagnosis according the 2017 revised McDonald criteria
• disease course: PPMS according to the 2013 revised Lublin criteria
• disease severity: Expanded Disability Status Scale (EDSS) score ≤ 6.0
• Informed Consent as documented by signature of participants and PI

Exclusion Criteria:

• Persons suffering from severe lower extremity spasticity or severe concomitant ´ disease states (i.e., orthopaedic, cardiovascular, metabolic, psychiatric (e.g., substance abuse), other neurological, other serious medical conditions) impairing their ability to participate.
• Persons regularly performing HIIT (2-3 times per week)
• Inability to follow the procedures of the study due to language problems (i.e., participant not fluent in oral and written German language)
• Changes in disease-modifying drugs (≤ 6 weeks)
• Immunosuppressive therapy (i.e., corticosteroids) (≤ 4 weeks)
• Stem cell treatment (≤ 6 months)
• Pregnant or breast-feeding women
• Intention to become pregnant during the course of the study
• Suspected non-compliance
• Previous enrolment into the current study
• Enrolment of the investigator, his/her family members, employees, and other dependent persons
• occurrence of severe pulmonary or cardiovascular decompensations (i.e., blood pressure (Riva Rocci) > 240/120, HR ≥ HRmax (220-years of age) (e.g. due to renal failure, hepatic dysfunction, cardiovascular disease)
• abnormalities in electrocardiography (ECG), pulse oximetry, or spirometry during initial CPET