The Influence of Passive and Active Post-Prandial Standing on Systemic Metabolism in People with Spinal Cord Injury

Michael Petrie; Olga Dubey; Chishan Shiao; Richard Shields

doi:10.1152/physiol.2025.40.S1.0237

Abstract only Introduction: People living with spinal cord injury (SCI) are at an extreme disadvantage to regulate systemic metabolism and glucose homeostasis, contributing to high rates of cardiometabolic disease development, lower life expectancy, and poorer life quality compared to the general population. The body enters a state of metabolic chaos after SCI, resulting in a catabolic state where muscle below the lesion level atrophies and transitions to a metabolic quiescent phenotype, compromising systemic metabolism. Therefore, there is a need for feasible, effective rehabilitation strategies that target improving metabolic health after SCI. Breaking up prolonged periods of sitting with periods of standing and exercise is well known to improve systemic metabolic function and prevent post-prandial hyperinsulinemia among people without SCI. Significant barriers prevent people with SCI from engaging in these similar types of activities. The purpose of this study was to determine how various positions, with and without electrically induced exercise, influences systemic metabolism before and after a meal among people with SCI. Methods: Ten male participants with SCI completed 2 studies. In study 1, participants complete 2 sessions where the participants were position into a seated, supine, and standing positions after completing an overnight fast using a Permobil Inc. electric wheelchair. In study 2, participants completed 3 sessions where they ingested a standardized solid mixed meal (protein bars) after an overnight fast. After completing the meal, participants transitioned to a standing position or remained seated. During one standing session the participants stood passively, while during the other standing session they performed an exercise bout using bilateral 3Hz electrical stimulation of their quadriceps and calf muscles (active stance). Venous blood was sampled at the end of each position during study 1 and at 10-minute increments during study 2. Glucose, insulin, and lactate concentrations were measured for all venous blood samples. Results: In study 1, we found a that passive stance while fasting decreased blood insulin concentrations by ~20% (p = 0.004) without an associated decrease in glucose concentrations (~3%, p = 0.33) compared to the seated position. There were no observed changes of glucose or insulin between the seated and supine positions. In study 2, we found that post-prandial glucose (~1%, p = 0.95), insulin (>0.1%, p = 1.0), or lactate (~8%, p=0.93) concentrations were unchanged compared to passive sitting. However, there was over 50% decrease in insulin (p < 0.001), 115% increase in lactate, but no change in glucose (0.5%, p = 0.99) during active stance as compared to passive sitting. Discussion: These results support that passive upright stance may be beneficial in supporting metabolic health, particularly during intermittent fasting among people with SCI. Importantly, active stance effectively modulates post-prandial blood insulin concentrations after a meal. These results suggest that adding post-prandial stance, particularly when paired with exercise, may be a key lifestyle behavior to optimize metabolic health among people living with SCI. This study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development: R01HD084645 & R01HD082109 and by a Permobil, Inc. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

The Influence of Passive and Active Post-Prandial Standing on Systemic Metabolism in People with Spinal Cord Injury

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