Acu-TENS lowers blood lactate levels and enhances heart rate recovery after exercise

ObjectiveThe primary aim of this study is to investigate the effect of application of transcutaneous electrical nerve stimulation over acupuncture points (Acu-TENS) on post-exercise blood lactate level. The secondary aim is to explore the effect of Acu-TENS on heart rate recovery and its association with autonomic nervous system.MethodsTwenty healthy subjects (mean age 26.9 ± 1.3) acting as their own controls, were randomized to receive either Acu-TENS or Placebo-TENS as the first of two intervention protocols, implemented one week apart. During Acu-TENS, subjects received 45 min TENS bilaterally over the acupoints Neiguan (PC6). Subjects receiving Placebo-TENS had identical electrode placement but with no electrical output from the TENS unit despite an active output light. Interventions were followed by a 10-min ergometer exercise at 70% age-predicted maximal heart rate. Oxygen consumption and heart rate (HR) were recorded continuously throughout exercise. Blood lactate and blood pressure were taken at 4 time points: prior to, immediately after, at 15-min after exercise, and when HR had returned to baseline values.ResultsThe post-exercise blood lactate level in the Acu-TENS group was lower than that of the placebo group by 1.12 ± 0.39 mmol/L (p = 0.01). The Acu-TENS group also had a faster return of HR to pre-exercise level compared to placebo (9.98 ± 4.54 min, p = 0.047). Heart rate variability analysis inferred reduced sympathetic modulation during exercise after Acu-TENS. There was no between-group difference in post-exercise oxygen consumption.ConclusionAcu-TENS lowered post-exercise blood lactate level and enhanced heart rate recovery after moderate exercise. The role of Acu-TENS in exercise performance and energy metabolism warrants further investigation. (ClinicalTrails.gov Identifier: NCT01102634)