Seven relevant studies were identified (83 patients): three RCTs, one of which was a cross-over trial (62 patients, range 14 to 26; all provided level II evidence, with one strong, one medium and one weak quality RCT); two case series (16 patients, both with eight participants and both level IV studies); and two case reports (5 patients, both provided level V evidence). Two of the RCTs used a follow-up period. None performed a power calculation.
Level II evidence:
The strong-quality cross-over RCT II (11 patients in each group) found significant improvements (p<0.05) with aerobic exercise for the 6-minute walk test, perception of breathlessness, peak oxygen consumption (VO2peak), rate of oxygen consumption/kg and peak double product.
The moderate-quality RCT II (26 patients) also found a significant benefit for aerobic exercise for cardiovascular fitness (p=0.05), functional ability and habitual activity (p=0.003), but this appeared to be associated with a decrease in functional ability in the control group (who attended talks) rather than an increase in the exercise group.
The weak-quality RCT II (4 to 6 patients in each treatment group) had both Parkinson’s disease and healthy controls and found significant benefits for aerobic exercise with VO2peak, power and movement initiation in choice conditions. The authors questioned the validity of the assessment of VO2peak and movement initiation and identified a lack of blinding.
Evidence from level IV and V studies was also presented.
Intensity of intervention: The strong-quality RCT II showed that the minimum number of sessions required for a significant improvement was 21 (50-minute sessions, three times a week for seven weeks). Most other trials used 24 to 36 sessions over 12 weeks.