Abstract
<p>Several exercise-related Parkinson’s Disease (PD) studies have provided evidence for exercise benefits in PD management. However, one important issue that remains is a lack in understanding of basic physiological responses to exercise in comparison to non-PD (nPD) individuals. Exercise responses and metabolic efficiency in PD are vital for creating optimal and responsible exercise protocols for clinical, research, and recreational settings. Metabolic biomarkers, such as lactate, can provide information on metabolic function at rest, during, and post exercise in PD individuals yet few studies have evaluated these variables in response to graded exercise testing in comparison to nPD groups.</p>
<p>The aim of this quasi-experimental and observational study was to provide further insight into PD-specific exercise performance, metabolic function, and physical activity level. The primary goals for the study were to determine associations and compare markers of exercise performance (i.e., submaximal and peak VO2 and total work) and metabolic function (i.e., lactate, respiratory exchange ratio [RER], and work efficiency) during a maximal graded exercise test (GXT), in addition to objective and subjective measures of physical activity (PA) level (i.e., step count, duration and intensity of PA) in PD and nPD individuals. Relationships among exercise performance, metabolic function, and PA level were also evaluated in correlation with PD symptom severity (i.e., motor symptoms, non-motor symptoms, and cognitive status).</p>
<p>The preliminary results showed that no significant differences existed between PD (n = 3, age: 62.33 ± 9.30 yrs) and nPD (n = 2, age: 67.0 ± 9.90 yrs) individuals of the given sample populations (p < .05). Observed trends suggested that the PD group had better exercise performance and metabolic function, and higher levels of PA when compared to the nPD group. Within the PD group, higher severity of motor symptoms seemed to result in greater deficits in exercise and metabolic outcomes whereas higher non-motor symptom severities were associated with higher outcomes of exercise performance and metabolic function. Greater duration of PA seemed more strongly associated with higher cognitive function than with motor or non-motor symptoms, with low and vigorous intensities tending to be associated with better cognition.</p>
<p>Overall, the current findings suggest that PD alone may not be the only factor that influences exercise performance and metabolic function. Levels of PA, age, disease duration, or even body composition should be further analyzed as co-factors using a larger sample population. Continued research in exercise responses for PD is warranted for a better understanding of PD-specific exercise physiology and personalized exercise prescription.</p>