Interaction Between Exercise Intensity and Sedentary Behavior on VO2max Change in Patients with De Novo Parkinson Disease: The Study in Parkinson Disease of Exercise (SPARX) Phase 2 Randomized Clinical Trial
- 1Center for Visual and Neurocognitive Rehabilitation (CVNR), Atlanta VAMC, Decatur, GA, USA
Abstract
BackgroundParkinson disease (PD) is associated with increased sedentary time and reduced cardiorespiratory fitness, making exercise an important component of disease management. Although exercise improves cardiorespiratory fitness, individuals with PD vary substantially in their response to exercise. Sedentary time may contribute to this variability, yet whether sedentary time modifies the response to intervention and varying exercise intensities within an intervention is unknown. We examined whether sedentary time interacted with 6 months of moderate-intensity or high- intensity aerobic exercise on maximal oxygen consumption (VO2max) in individuals with PD.
MethodsThis secondary analysis used data from the SPARX phase 2 randomized clinical trial including 128 de novo PD patients assigned to high- or moderate-intensity treadmill exercise, or usual care for 6 months. Interactions between randomized group and post-randomization 6-months average sedentary time were assessed for associations with 6-month change in VO2max by using linear regression models corresponding to Analysis of Covariance (ANCOVA) models with interaction.
ResultsThe interaction between exercise intensity and sedentary behavior on 6-month change in VO2max in the moderate-intensity group compared with usual care was not significant ({beta}: -1.78, 95% CI: -3.76 to 0.20, p-value: 0.08), although the sensitivity analysis restricted to complete cases showed a significant interaction where each 10% increase in 6-months average sedentary time was associated with a 2.51 mL/kg/min decrease in VO2max change in the moderate-intensity group compared with usual care ({beta}: -2.51, 95% CI: -4.53 to -0.48, p-value: 0.02). There was no significant interaction between exercise intensity and sedentary behavior on 6-month change in VO2max in the high-intensity group compared with usual care ({beta}: -1.46, 95% CI: -4.74 to 1.83, p-value: 0.38). The sensitivity analysis showed similar results.
ConclusionsThese hypothesis-generating, preliminary findings suggest that sedentary time may modify the response to exercise among individuals participating in moderate-intensity aerobic exercise. Future adequately powered randomized controlled trials are needed to confirm these findings and determine whether sedentary behavior should be considered when prescribing exercise for individuals with PD.
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BibTeX
@misc{pae2026interaction,
title = {{Interaction Between Exercise Intensity and Sedentary Behavior on VO2max Change in Patients with De Novo Parkinson Disease: The Study in Parkinson Disease of Exercise (SPARX) Phase 2 Randomized Clinical Trial}},
author = {B. J. Pae and T. S. Novak and G. J. Griffith and C. G. Patterson and M. E. Hackney and C. L. Christiansen and D. M. Corcos and J. R. Nocera},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.30.26364437},
url = {https://www.medrxiv.org/content/10.64898/2026.09.30.26364437v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Interaction Between Exercise Intensity and Sedentary Behavior on VO2max Change in Patients with De Novo Parkinson Disease: The Study in Parkinson Disease of Exercise (SPARX) Phase 2 Randomized Clinical Trial
AU - B. J. Pae
AU - T. S. Novak
AU - G. J. Griffith
AU - C. G. Patterson
AU - M. E. Hackney
AU - C. L. Christiansen
AU - D. M. Corcos
AU - J. R. Nocera
PY - 2026
DA - 2026/09/30
PB - medRxiv
DO - 10.64898/2026.09.30.26364437
UR - https://www.medrxiv.org/content/10.64898/2026.09.30.26364437v1
AB - BackgroundParkinson disease (PD) is associated with increased sedentary time and reduced cardiorespiratory fitness, making exercise an important component of disease management. Although exercise improves cardiorespiratory fitness, individuals with PD vary substantially in their response to exercise. Sedentary time may contribute to this variability, yet whether sedentary time modifies the response to intervention and varying exercise intensities within an intervention is unknown. We examined whether sedentary time interacted with 6 months of moderate-intensity or high- intensity aerobic exercise on maximal oxygen consumption (VO2max) in individuals with PD. MethodsThis secondary analysis used data from the SPARX phase 2 randomized clinical trial including 128 de novo PD patients assigned to high- or moderate-intensity treadmill exercise, or usual care for 6 months. Interactions between randomized group and post-randomization 6-months average sedentary time were assessed for associations with 6-month change in VO2max by using linear regression models corresponding to Analysis of Covariance (ANCOVA) models with interaction. ResultsThe interaction between exercise intensity and sedentary behavior on 6-month change in VO2max in the moderate-intensity group compared with usual care was not significant ({beta}: -1.78, 95% CI: -3.76 to 0.20, p-value: 0.08), although the sensitivity analysis restricted to complete cases showed a significant interaction where each 10% increase in 6-months average sedentary time was associated with a 2.51 mL/kg/min decrease in VO2max change in the moderate-intensity group compared with usual care ({beta}: -2.51, 95% CI: -4.53 to -0.48, p-value: 0.02). There was no significant interaction between exercise intensity and sedentary behavior on 6-month change in VO2max in the high-intensity group compared with usual care ({beta}: -1.46, 95% CI: -4.74 to 1.83, p-value: 0.38). The sensitivity analysis showed similar results. ConclusionsThese hypothesis-generating, preliminary findings suggest that sedentary time may modify the response to exercise among individuals participating in moderate-intensity aerobic exercise. Future adequately powered randomized controlled trials are needed to confirm these findings and determine whether sedentary behavior should be considered when prescribing exercise for individuals with PD.
ER -