Electrically induced standing exercise modulates autonomic balance and improves postprandial glucose metabolism in people with spinal cord injury

Introduction: Individuals with spinal cord injury (SCI) with lesions above the sixth thoracic vertebra suffer from autonomic dysreflexia and long-term metabolic complications. The paralysis of large lower extremity muscles and loss of sympathetic control promote severe orthostatic hypotension which limits many people with SCI from standing. Importantly, muscle atrophy and transformation to glycolytic muscle led to reduced insulin sensitivity and risk of developing Type 2 Diabetes. Electrically induced exercise while standing using low frequency but high intensity electrical stimulation may offer to assist with venous return of blood, prevent orthostatic hypotension, and be a particularly useful activity after a meal. We previously showed that low frequency exercise in the seated position reduces post-prandial insulin spikes. The purpose of this study was to compare the effects of passive standing versus electrically induced active standing on sympathetic vagal balance and postprandial insulin response among people with various levels of SCI. We hypothesize that electrically induced active standing will modulate autonomic control. We also propose that the magnitude of sympathetic to parasympathetic regulation will be associated with the postprandial attenuation of insulin during electrically induced stance among people with SCI. Methods: Nine adult males with SCI (5 cervical level, four thoracic level) participated in the study. The participants fasted for 8 hours prior to the study. Testing sessions included pre- and postprandial seated control and passive standing and postprandial active standing. Active standing involved the application of 3Hz functional electrical stimulation on bilateral quadriceps and gastrocnemius muscles. We measured each participant’s blood insulin level via blood sampling and continuously recorded heart rate (HR) during sitting, passive and active standing. Frequency domain analysis of heart rate variability (HRV) was conducted to calculate low frequency power (LF), high frequency power (HF), and low to high frequency power ratio (LF/HF ratio). Electrical stimulation-induced artifacts were identified and excluded from the HRV analysis. Results: During fasting, passive standing showed lower insulin level (~20%, p=0.012), LF (~47%, p=0.038), and HF (~55%, p=0.038) and higher HR (~19%, p=0.008) and LF/HF ratio (~110%, p=0.011) than sitting. In postprandial state, active standing resulted in decreased insulin level ( >50%, p< 0.001) compared to passive standing. In addition, while HR remained stable between two standing conditions, active standing showed consistent trends towards lower values of LF, HF, and LF/HF ratio. We found a strong correlation between the magnitude of change in post prandial attenuation of insulin with active stance and the high frequency power of the HRV (r=0.900, p=0.037). These findings suggest that applying electrical muscle stimulation is beneficial for maintaining metabolic and cardiovascular function during postprandial stand training for individuals with SCI. Furthermore, positive correlation between the HF and postprandial attenuation in insulin suggests that individuals with better autonomic adaptability received larger metabolic benefit from active standing. Conclusions: Electrically induced active standing is highly effective for modulating metabolic and autonomic physiological responses among people with SCI and may offer an alternative approach to reduce risk of cardiometabolic diseases. Funding Source: Permobil, Inc., Lebanon, TN This abstract was presented at the American Physiology Summit 2026 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.