Transcutaneous Electrical Nerve Stimulation Improves Exercise Tolerance in Healthy Subjects

Transcutaneous electrical nerve stimulation (TENS) increases peripheral blood flow by attenuation of the muscle metaboreflex, improving oxygen supply to working muscles. We tested the hypothesis that application of TENS at ganglion improves exercise performance. 11 subjects underwent constant-work rate tests (CWR) to the limit of tolerance (Tlim) while receiving TENS or placebo. Oxygen uptake (V.O2), carbon dioxide (V.CO2), minute ventilation (V.E), ventilatory equivalent (V.E/V.CO2), heart rate (HR) and oxygen pulse (V.O2/HR) were analyzed at isotime separated by percentile and Tlim. V.O2 was lower and V.CO2 was higher at 100% of isotime during TENS, while there were no differences in V.E and V.E/V.CO2. HR was lower during exercise with TENS, and V.O2/HR increased at peak exercise (17.96±1.9 vs. 20.38±1 ml/min/bpm, P<0.05). TENS increased mechanical efficiency at isotime and Tlim (4.10±0.50 vs. 3.39±0.52%, P<0.05 and 3.95±0.67 vs. 3.77±0.45%, P<0.05) and exercise tolerance compared to P-TENS (390±41 vs. 321±41 s; P<0.05). Our data shows that the application of TENS can potentially increase exercise tolerance and oxygen supply in healthy subjects.