Training & Testing
661
Authors
F. P. Tomasi1, G. Chiappa2, V. Maldaner da Silva3, M. Lucena da Silva1, A. S. C. G. B. Lima1, R. Arena4, M. Bottaro5, G. Cipriano3
Affiliations
Affiliation addresses are listed at the end of the article
Key words ▶ hemodynamics ● ▶ stimulation ● ▶ exercise tolerance ●
Abstract
▼
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 (VO2), carbon dioxide . . (VCO2), minute ventilation (VE), ventilatory . . equivalent (VE/VCO2), heart rate (HR) and oxygen . pulse (VO2/HR) were analyzed at isotime sepa-
Introduction
▼
accepted after revision July 13, 2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1387763 Published online: January 21, 2015 Int J Sports Med 2015; 36: 661–665 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Dr. Gerson Cipriano Jr Physical Therapy University of Brasilia QNN 14 Área Especial Ceilandia Brazil 72220-140 Tel.: + 55/337/60 252 Fax: + 55/819/07 111 [email protected]
Several studies have shown the effects of transcutaneous electrical nerve stimulation (TENS) on blood flow [12, 24]. Recently, we tested the effect of TENS on the muscle metaboreflex, which is important to blood flow control during exercise mediated by the activation of mechanosensitive and metabosensitive afferents within the active skeletal muscle [23]. In our study, TENS attenuated blood flow redistribution during post-exercise circulatory occlusion in healthy subjects, which supports the hypothesis that acute TENS improves peripheral muscle blood flow and decreases sympathetic activity assessed by heart rate variability [26]. It has been suggested that these effects may be linked to the release of β-endorphin by an agonistic effect on local μ-opioid-receptors [20], which appears to be a key mechanism for modulating blood pressure, increasing oxygen delivery to active skeletal muscle. In addition, there are other proposed mechanisms, such as inhibition of sympathetic activity, which might explain the vascular effect [17, 21]. The physiologic mechanisms by which TENS induces cardiovascular benefits remain to be elucidated. Evidence suggesting that TENS may attenuate the increase of blood
. rated by percentile and Tlim. VO2 was lower and . VCO2 was higher at 100 % of isotime during TENS, . . . while there were no differences in VE and VE/V CO2. HR was lower during exercise with TENS, . and VO2/HR increased at peak exercise (17.96 ± 1.9 vs. 20.38 ± 1 ml/min/bpm, P
661
Authors
F. P. Tomasi1, G. Chiappa2, V. Maldaner da Silva3, M. Lucena da Silva1, A. S. C. G. B. Lima1, R. Arena4, M. Bottaro5, G. Cipriano3
Affiliations
Affiliation addresses are listed at the end of the article
Key words ▶ hemodynamics ● ▶ stimulation ● ▶ exercise tolerance ●
Abstract
▼
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 (VO2), carbon dioxide . . (VCO2), minute ventilation (VE), ventilatory . . equivalent (VE/VCO2), heart rate (HR) and oxygen . pulse (VO2/HR) were analyzed at isotime sepa-
Introduction
▼
accepted after revision July 13, 2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1387763 Published online: January 21, 2015 Int J Sports Med 2015; 36: 661–665 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Dr. Gerson Cipriano Jr Physical Therapy University of Brasilia QNN 14 Área Especial Ceilandia Brazil 72220-140 Tel.: + 55/337/60 252 Fax: + 55/819/07 111 [email protected]
Several studies have shown the effects of transcutaneous electrical nerve stimulation (TENS) on blood flow [12, 24]. Recently, we tested the effect of TENS on the muscle metaboreflex, which is important to blood flow control during exercise mediated by the activation of mechanosensitive and metabosensitive afferents within the active skeletal muscle [23]. In our study, TENS attenuated blood flow redistribution during post-exercise circulatory occlusion in healthy subjects, which supports the hypothesis that acute TENS improves peripheral muscle blood flow and decreases sympathetic activity assessed by heart rate variability [26]. It has been suggested that these effects may be linked to the release of β-endorphin by an agonistic effect on local μ-opioid-receptors [20], which appears to be a key mechanism for modulating blood pressure, increasing oxygen delivery to active skeletal muscle. In addition, there are other proposed mechanisms, such as inhibition of sympathetic activity, which might explain the vascular effect [17, 21]. The physiologic mechanisms by which TENS induces cardiovascular benefits remain to be elucidated. Evidence suggesting that TENS may attenuate the increase of blood
. rated by percentile and Tlim. VO2 was lower and . VCO2 was higher at 100 % of isotime during TENS, . . . while there were no differences in VE and VE/V CO2. HR was lower during exercise with TENS, . and VO2/HR increased at peak exercise (17.96 ± 1.9 vs. 20.38 ± 1 ml/min/bpm, P
