High

To investigate whether people with Parkinson’s disease can exercise at a high-intensity across a 12-week intervention and to assess the impact of the intervention on cardiorespiratory fitness. This is a randomized, controlled, feasibility study with waiting list control. Assessors were blinded to group allocation. The intervention took place at an exercise centre and assessments at a district general hospital. This study included 20 people with idiopathic Parkinson’s disease. A total of 36 exercise sessions over 12？weeks, with each session lasting ~45？minutes, were conducted. The main measures were maximal heart rates achieved during exercise, recruitment rate, attendance, drop-out, change in peak oxygen consumption, cardiac output, cognitive function and quality of life. The study was considered technically feasible if participants achieved ？85% of maximal heart rate during exercise. There were 12 male and 8 female participants; they had a mean age of 68.5？years (standard deviation 6.825). Two participants were of Hoehn and Yahr stage I, 11 stage II and 7 stage III. In all, 17 participants completed the intervention. The median (interquartile range) proportion of repetitions delivered across the intervention which met our high-intensity criterion was 80% (67% to 84%). Mean peak heart rate was 88.8% of maximal. Peak oxygen consumption increased by 2.8？mL？kg？1？min？1 in the intervention group and 1.5？mL？kg？1？min？1 in the control group after 12？weeks of exercise. We estimate that a fully powered randomized controlled trial would require 30 participants per group. High-intensity interval exercise is feasible in people with Parkinson’s disease. Improvements in cardiorespiratory function are promising