Cardiopulmonary exercise testing-based high-intensity interval training delivered via synchronous telehealth for metabolic dysfunction-associated steatotic liver disease: protocol of the CPHIT-1 study.

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is becoming a leading chronic liver disease worldwide. Although exercise-centred lifestyle therapy is promising, there is still a lack of scalable, individually tailored exercise intervention strategies that can be implemented in daily practice.

OBJECTIVES

To investigate the efficacy, safety and adherence of a synchronous telehealth-delivered, cardiopulmonary exercise testing (CPET)-based high-intensity interval training (HIIT) programme, compared with a guideline-based lifestyle advice control, in adults with MASLD.

METHODS AND

DESIGN

This prospective, multicentre randomised controlled trial enrolled 56 participants (aged 35-65 years) with ultrasound-confirmed hepatic steatosis, randomised (1:1) to HIIT or control. The HIIT programme comprised a 2-week run-in phase for protocol titration, followed by an 8-week home-based phase of 4 cycling sessions per week. Each session was supported by synchronous telehealth delivery, including monitoring of exercise quality via mobile hardware devices and real-time video supervision to safeguard exercise safety. Sessions consisted of 8 sets of 30s intervals at high intensity (80-90% peak VO2) separated by 60s active pauses (60-70% peak VO2). All participants received guideline-based lifestyle advice, and their usual physical activity was maintained throughout the trial. The primary endpoint was change in liver fat content after 8 weeks, assessed by magnetic resonance imaging proton-density fat-fraction; secondary endpoints included liver stiffness measurement, body mass index, cardiorespiratory fitness, overtraining metrics and protocol feasibility.