Effect of Acu-TENS on recovery heart rate after treadmill running exercise in subjects with normal health

Objective: This study aims to investigate the effect of transcutaneous electrical nerve stimulation, applied at bilateral acupuncture points PC6 (Acu-TENS), on recovery heart rate (HR) in healthy subjects after treadmill running exercise. Design: A single blinded, randomized controlled trial. Setting: Laboratory with healthy male subjects (n = 28). Interventions: Each subject participated in three separate protocols in random order. Protocol A: The subject followed the Bruce protocol and ran on a treadmill until their HR reached 70% of their maximum (220-age). At this 'target' HR, the subject adopted the supine position and Acu-TENS to bilateral PC6 was commenced. Protocol B: Identical to protocol A except that Acu-TENS was applied in the supine position for 45 min prior to, but not after exercise. Protocol C: Identical to protocol A except that placebo Acu-TENS was applied. Main outcome measures: Heart rate was recorded before and at 30 s intervals after exercise until it returned to the pre-exercise baseline. The time for HR to return to baseline was compared for each protocol. Results: Acu-TENS applied to bilateral PC6 resulted in a faster return to pre-exercise HR compared to placebo. Time required for HR to return to pre-exercise level in protocols A-C was 5.5 ± 3.0; 4.8 ± 3.3; 9.4 ± 3.7 min, respectively (p < 0.001). There was no statistical difference in HR recovery time between protocols A and B. Subjects expressed the lowest rate of perceived exertion score (RPE) at 70% maximum HR with protocol B. Conclusion: This study suggests that Acu-TENS applied to PC6 may facilitate HR recovery after high intensity treadmill exercise.Department of Rehabilitation Science