Slow-SPEED: Slowing Parkinson's Early Through Exercise Dosage

The goal of this clinical trial is two-fold. First to investigate the feasibility of whether a remotely administered smartphone app can increase the volume and intensity of physical activity in daily life in individuals with a LRRK2 G2019S or GBA1 N370S genetic mutation over a long period of time (24 months). Second, to explore the preliminary efficacy of exercise on markers for prodromal Parkinson's disease progression in individuals with a LRRK2 G2019S or GBA1 N370S genetic mutation. Participants will be tasked to achieve an incremental increase of daily steps (volume) and amount of minutes exercised at a certain heart rate (intensity) with respect to their own baseline level. Motivation with regards to physical activity will entirely be communicated through the study specific Slow Speed smartphone app. A joint primary objective consists of two components. First to determine the longitudinal effect of an exercise intervention in LRRK2 G2019S or GBA1 N370S variant carriers on a prodromal load score, comprised of digital biomarkers of prodromal symptoms. The secondary component of the primary outcome is to determine the feasibility of a remote intervention study. The secondary objective is the effect of a physical activity intervention on digital markers of physical fitness. Exploratory outcomes entail retention rate, completeness of remote digital biomarker assessments, digital prodromal motor and non-motor features of PD. Using these biomarkers, the investigators aim to develop a composite score (prodromal load score) to estimate the total prodromal load. An international exercise study with fellow researchers in the United Kingdom are currently in preparation (Slow-SPEED-UK) and active in the Netherlands (Slow-SPEED-NL). Our intention is to analyse overlapping outcomes combined where possible through a meta-analysis plan, to obtain insight on (determinants of) heterogeneity in compliance and possible efficacy across subgroups