Aerobic capacity in persons with Parkinson's disease: a systematic review.

Abstract

To systematically review studies assessing (1) psychometric properties of the maximal oxygen uptake (VO_2max) test in PD, (2) VO_2max levels in persons with PD (pwPD) compared to healthy controls (HCs), and (3) reported VO_2max associations in PD. Six databases were searched. Descriptive data synthesis was used to summarize psychometric properties and reported VO_2max associations. The VO_2max means and test end-criteria were calculated using linear mixed models. Simple linear regression was used for associations. The review included 25 studies. Psychometric properties of the VO_2max test, reported in one study, showed intraclass correlations of 0.90-0.94 for VO_2max. Thirteen studies reported test end-criteria, with only mean respiratory exchange ratio (on medication) and percentage of predicted maximal heart rate (off medication) fulfilling standardized minimum values for the VO_2max test. The VO_2max was comparable between pwPD and HC as well as between different PD-medication states. Associations between VO_2max and age, sex, and fatigue were reported. In mildly to moderately affected pwPD, limited evidence exists on the psychometric properties of the VO_2max test and end-criteria were sparsely reported. Surprisingly, VO_2max was comparable between pwPD and HC as well as between different PD-medication states, and only age, sex, and fatigue were associated with VO_2max. Implications for rehabilitationIn mildly to moderately affected persons with PD (pwPD), only one study has examined psychometric properties of the VO_2max test, reporting excellent test-retest reliability.A general lack of consistency on how to measure and report VO_2max end-criteria was observed, but when reported, the end-criteria were most often not met.No difference was found in VO_2max between mildly to moderately affected pwPD and HC, or between pwPD across different medication states.The identified negative association between VO_2max and fatigue suggests aerobic exercise as a potential symptomatic treatment of fatigue when rehabilitation professionals are treating pwPD.