RT Journal Article
SR Electronic
T1 Nitric oxide synthase-derived plasma nitrite predicts exercise capacity
JF British Journal of Sports Medicine
JO Br J Sports Med
FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine
SP 669
OP 673
DO 10.1136/bjsm.2007.035758
VO 41
IS 10
A1 Tienush Rassaf
A1 Thomas Lauer
A1 Christian Heiss
A1 Jan Balzer
A1 Sarah Mangold
A1 Thorsten Leyendecker
A1 Jessica Rottler
A1 Christine Drexhage
A1 Christian Meyer
A1 Malte Kelm
YR 2007
UL http://bjsm.bmj.com/content/41/10/669.abstract
AB Background: Nitrite is the main oxidation product of nitric oxide (NO) in plasma. It sensitively reflects changes in endothelial NO synthase (eNOS) activity under fasting conditions and serves as an endocrine NO donor, contributing to the regulation of blood flow through reaction with haemoglobin. As NO is necessary to maintain an adequate vascular response to the increased demands of blood flow, it is believed to be important for vasodilation induced by exercise.Objective: To investigate whether the capacity of the vasculature to produce nitrite is associated with exercise performance.Design: With the use of chemiluminescence detection, nitrite concentrations in 55 healthy subjects (mean (SEM) age 40 (2) years; 22 men) were studied before and after an exercise test, and endothelial function was determined by measuring flow-mediated dilation of the brachial artery using high-resolution ultrasound. In a subset of subjects, the NOS inhibitor, NG-monomethyl-l-arginine, was applied to elucidate the effect of eNOS on changes in nitrite.Results: Exercise significantly (p<0.001) increased plasma nitrite from 97 (6) to 125 (8) nM. The relative increase in plasma nitrite was related to flow-mediated dilation (6.1 (0.3)%; r = 0.36; p = 0.01). NG-Monomethyl-l-arginine blocked increases in nitrite. Post-exercise nitrite concentration correlated with exercise performance, as determined by maximally reached stress power (r = 0.37; p<0.007), and inversely with age. Multivariate analysis showed that both age and post-exercise nitrite concentration were independent predictors of stress endurance and power.Conclusion: The results suggest a role for plasma nitrite in the adaptation of haemodynamics during exercise. An impaired increase in plasma nitrite may limit exercise capacity.