Physiological responses to moderate intensity continuous and high-intensity interval exercise in persons with paraplegia

David W McMillan, Jennifer L Maher, Kevin A Jacobs, Mark S Nash, James L J Bilzon

Research output: Contribution to journalArticle

Abstract

Study design: Randomized crossover. Objectives: To test differences in the duration and magnitude of physiological response to isocaloric moderate intensity continuous (MICE) and high-intensity interval exercise (HIIE) sessions in persons with spinal cord injury (SCI). Setting: Academic medical center in Miami, FL, USA. Methods: Ten adult men (mean ± s.d.; 39 ± 10 year old) with chronic (13.2 ± 8.8 year) paraplegia (T2–T10) completed a graded exercise test. Then, in a randomized order, participants completed MICE and HIIE for a cost of 120 kcal. MICE was performed at 24.6% PO peak. During HIIE, exercise was completed in 2 min work and recovery phases at 70%:10% PO peak. Results: MICE and HIIE were isocaloric (115.9 ± 21.8 and 116.6 ± 35.0 kcal, respectively; p = 0.903), but differed in duration (39.8 ± 4.6 vs 32.2 ± 6.2 min; p < 0.001) and average respiratory exchange ratio (RER; 0.90 ± 0.08 vs 1.01 ± 0.07; p = 0.002). During MICE, a workrate of 24.6 ± 6.7% PO peak elicited a V̇O 2 of 53.1 ± 6.5% V̇O 2peak (10.1 ± 2.2 ml kg −1 min −1). During HIIE, a workrate at 70% PO peak elicited 88.3 ± 6.7% V̇O 2peak (16.9 ± 4.2 ml kg −1 min −1), and 29.4 ± 7.7% of the session was spent at or above 80% V̇O 2peak. During HIIE working phase, RER declined from the first to last interval (1.08 ± 0.07 vs 0.98 ± 0.09; p < 0.001), reflecting an initially high but declining glycolytic rate. Conclusions: Compared with MICE, HIIE imposed a greater physiological stimulus while requiring less time to achieve a target caloric expenditure. Thus, exercise intensity might be an important consideration in the tailoring of exercise prescription to address the cardiometabolic comorbidities of SCI.

Original languageEnglish
Number of pages27
JournalSpinal Cord
Early online date17 Jul 2020
DOIs
Publication statusE-pub ahead of print - 17 Jul 2020

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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