ABSTRACT
Muscle deconditioning and impaired vascular function in the lower extremities (LE) are among the long‐term symptoms experienced by COVID‐19 patients with a history of severe illness. These symptoms are part of the post‐acute sequelae of Sars‐CoV‐2 (PASC) and currently lack evidence‐based treatment. To investigate the efficacy of lower extremity electrical stimulation (E‐Stim) in addressing PASC‐related muscle deconditioning, we conducted a double‐blinded randomized controlled trial. Eighteen (n = 18) patients with LE muscle deconditioning were randomly assigned to either the intervention (IG) or the control (CG) group, resulting in 36 LE being assessed. Both groups received daily 1 h E‐Stim on both gastrocnemius muscles for 4 weeks, with the device functional in the IG and nonfunctional in the CG. Changes in plantar oxyhemoglobin (OxyHb) and gastrocnemius muscle endurance (GNMe) in response to 4 weeks of daily 1 h E‐Stim were assessed. At each study visit, outcomes were measured at onset (t0), 60 min (t60), and 10 min after E‐Stim therapy (t70) by recording ΔOxyHb with near‐infrared spectroscopy. ΔGNMe was measured with surface electromyography at two time intervals: 0–5 min (Intv1) and: 55–60 min (Intv2). Baseline OxyHb decreased in both groups at t60 (IG: p = 0.046;CG: p = 0.026) and t70 (IG = p = 0.021;CG: p = 0.060) from t0. At 4 weeks, the IG's OxyHb increased from t60 to t70 (p < 0.001), while the CG's decreased (p = 0.003). The IG had higher ΔOxyHb values than the CG at t70 (p = 0.004). Baseline GNMe did not increase in either group from Intv1 to Intv2. At 4 weeks, the IG's GNMe increased (p = 0.031), whereas the CG did not change. There was a significant association between ΔOxyHb and ΔGNMe (r = 0.628, p = 0.003) at 4 weeks in the IG. In conclusion, E‐Stim can improve muscle perfusion and muscle endurance in individuals with PASC experiencing LE muscle deconditioning. This study indicates that self‐administered lower extremity (LE) electrical stimulation (E‐Stim) therapy is practical and effective at promoting the restoration of LE muscle perfusion and endurance in individuals with post‐acute sequelae of Sars‐CoV‐2 (PASC) who were previously hospitalized. The application of LE E‐Stim for 1 h daily over a 4 week period resulted in a significant increase in gastrocnemius muscle oxyhemoglobin levels, which led to an improvement in muscle endurance and recovery of excess postexercise oxygen consumption
ABSTRACT
Muscle deconditioning and impaired vascular function in the lower extremities (LE) are among the long-term symptoms experienced by COVID-19 patients with a history of severe illness. These symptoms are part of the post-acute sequelae of Sars-CoV-2 (PASC) and currently lack evidence-based treatment. To investigate the efficacy of lower extremity electrical stimulation (E-Stim) in addressing PASC-related muscle deconditioning, we conducted a double-blinded randomized controlled trial. Eighteen (n = 18) patients with LE muscle deconditioning were randomly assigned to either the intervention (IG) or the control (CG) group, resulting in 36 LE being assessed. Both groups received daily 1 h E-Stim on both gastrocnemius muscles for 4 weeks, with the device functional in the IG and nonfunctional in the CG. Changes in plantar oxyhemoglobin (OxyHb) and gastrocnemius muscle endurance (GNMe) in response to 4 weeks of daily 1 h E-Stim were assessed. At each study visit, outcomes were measured at onset (t0 ), 60 min (t60 ), and 10 min after E-Stim therapy (t70 ) by recording ΔOxyHb with near-infrared spectroscopy. ΔGNMe was measured with surface electromyography at two time intervals: 0-5 min (Intv1 ) and: 55-60 min (Intv2 ). Baseline OxyHb decreased in both groups at t60 (IG: p = 0.046; CG: p = 0.026) and t70 (IG = p = 0.021; CG: p = 0.060) from t0 . At 4 weeks, the IG's OxyHb increased from t60 to t70 (p < 0.001), while the CG's decreased (p = 0.003). The IG had higher ΔOxyHb values than the CG at t70 (p = 0.004). Baseline GNMe did not increase in either group from Intv1 to Intv2 . At 4 weeks, the IG's GNMe increased (p = 0.031), whereas the CG did not change. There was a significant association between ΔOxyHb and ΔGNMe (r = 0.628, p = 0.003) at 4 weeks in the IG. In conclusion, E-Stim can improve muscle perfusion and muscle endurance in individuals with PASC experiencing LE muscle deconditioning.